Patent Grant
12129812
The present subject matter relates generally to energy conversion systems, power generation systems, and energy distribution systems. The present subject matter additionally relates to heat exchangers and heat exchanger systems. The present subject matter further relates to piston engine assemblies, such as closed-cycle engine systems. The present subject matter still further relates to systems and methods for control or operation of one or more systems of the present subject matter herein.
Power generation and distribution systems are challenged to provide improved power generation efficiency and/or lowered emissions. Furthermore, power generation and distribution systems are challenged to provide improved power output with lower transmission losses. Certain power generation and distribution systems are further challenged to improve sizing, portability, or power density generally while improving power generation efficiency, power output, and emissions.
Certain engine system arrangements, such as closed cycle engines, may offer some improved efficiency over other engine system arrangements. However, closed cycle engine arrangements, such as Stirling engines, are challenged to provide relatively larger power output or power density, or improved efficiency, relative to other engine arrangements. Closed cycle engines may suffer due to inefficient combustion, inefficient heat exchangers, inefficient mass transfer, heat losses to the environment, non-ideal behavior of the working fluid(s), imperfect seals, friction, pumping losses, and/or other inefficiencies and imperfections. As such, there is a need for improved closed cycle engines and system arrangements that may provide improved power output, improved power density, or further improved efficiency. Additionally, there is a need for an improved closed cycle engine that may be provided to improve power generation and power distribution systems.
Additionally, or alternatively, there is a general need for improved heat transfer devices, such as for heat engines, or as may be applied to power generation systems, distribution systems, propulsion systems, vehicle systems, or industrial or residential facilities.
Furthermore, there is a need for improved control system and methods for operating power generation systems as may include subsystems that collectively may provide improved power generation efficiency or reduced emissions.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
An aspect of the present disclosure is directed to a system for energy conversion. The system includes a closed cycle engine containing a volume of working fluid, the engine comprising a first chamber defining an expansion chamber and a second chamber defining a compression chamber each separated by a piston attached to a connection member of a piston assembly, and wherein the engine comprises a heater body in thermal communication with the first chamber, and further wherein the engine comprises a cold side heat exchanger in thermal communication with the second chamber, and wherein a third chamber is defined within the piston, wherein the third chamber is in selective flow communication with the first chamber, the second chamber, or both.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure including the best mode, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present disclosure.
Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure and not limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. In another instance, ranges, ratios, or limits associated herein may be altered to provide further embodiments, and all such embodiments are within the scope of the present disclosure. Unless otherwise specified, in various embodiments in which a unit is provided relative to a ratio, range, or limit, units may be altered, and/or subsequently, ranges, ratios, or limits associated thereto are within the scope of the present disclosure. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.
As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “loop” can be any suitable fluid pathway along which fluid can flow and can be either open or closed, unless stated otherwise.
Generation, Conversion, and Distribution Systems
Power Generation, Engine and Energy Conversion Systems, and Energy Distribution Systems
Power generation and distribution systems are generally challenged to reduce production inefficiencies, transmission losses, and emissions (e.g., oxides of nitrogen, sulfur, or carbon) during and post energy production. For example, the U.S. Energy Information Administration (EIA) estimates that electricity transmission and distribution (T&D) losses average about 5% annually in the United States, with other estimates of line losses of 8% or higher. With average power plant efficiencies in the United States of about 30% to 40%, overall electrical efficiency at the end user (e.g., residences, businesses, etc.) is approximately 25% to 35%. Local, distributed, or on-demand power generation may not require access to T&D networks or grids, such as to result in an at least 5% improvement in efficiency, in addition to reducing emission and adverse environmental impacts.
In the United States, power generation may account for approximately one-third of national greenhouse gas emissions. Transportation may further account for another approximately one-third of national greenhouse gas emissions, about 85% of which may be from ground transportation vehicles (e.g., cars, trucks, buses, etc.). Known systems for reducing emissions include chemical or catalytic reduction after-treatment. However, such systems may be expensive to acquire and maintain, complex, or heavy, thereby reducing overall system efficiency. Additionally, such systems may be difficult to regulate, such that emissions reduction benefits may be lost after initial acquisition. Furthermore, although known systems have resulted in reducing emissions of high reactive gases such as unburned hydrocarbons, volatile organic compounds, or oxides of sulfur or nitrogen, emissions of greenhouse gases such as carbon dioxide may generally correspond or increase with power generation and consumption.
Power generation and distribution systems may turn to renewable energy sources such as solar, wind, or tidal energy to reduce emissions. However, renewable energy sources are often periodic or unpredictable, such as depicted in
Historically, peak power demand occurs in the mid-afternoon, such as due to high industrial usage. In contrast, power usage is historically lower during the overnight hours when residential and industrial usage is both relatively low. However, overnight power demand is expected to increase with increased electrification, such as with increased usage of electric vehicles. Additionally, daytime power demand may further increase, further increasing peak power demands. For example, full charging of electric vehicles may take 4 to 8 hours and may generally occur overnight when power usage is historically low. Additionally, or alternatively, electric vehicle charging may occur during the workday, such as after a morning commute and during business hours, which may further increase industrial power usage. Generally, current power generation and distribution systems are inflexible (e.g., due to cost and operational needs and restrictions) relative to changes in usage and demand throughout a day, such as depicted in regard to
In addition, or alternatively, power generation and distribution infrastructure is costly and renders large geographic areas vulnerable to power outages based on adverse weather, natural or man-made disasters, equipment malfunctions and failures, or maintenance activities. Initial and on-going costs, such as maintenance and repair, result in barriers to further development of access to electricity in developing countries and rural areas. Expanding access to electricity may be hindered by relatively high costs to establish generation and distribution infrastructure, relatively high operational costs, and an ability for governments, corporations, or consumers to pay or invest in power generation and distribution. Such costs may also pose barriers to further maintenance and development in developed countries, as older infrastructure and natural or man-made disasters may cause maintenance or improvement to be cost-prohibitive. For example, in the United States, power lines and transformers are approximately 30 years old on average. Replacement costs for such equipment have been estimated at over $1 trillion dollars.
Such issues and barriers from power generation and distribution systems may further pose barriers to developing or expanding access to clean water, water desalination, and food security. Additionally, or alternatively, smaller scale or portable power generation systems that may overcome distribution obstacles may nonetheless be challenged to provide a necessary power density and output. Such limitations in power density and output may generally result in an inability to apply smaller scale or portable power generation systems to rural areas or developing nations. Furthermore, as clean water treatment and desalination are generally energy intensive, smaller scale or portable power generation system may generally provide inadequate power density and output for providing water to rural or less population-dense areas.
As such, there is a need for power generation systems that provide improved efficiency and reduced emissions over known power generation systems that may further be sized or scaled to provide improved power distribution without adversely affecting efficiency and emissions. The need for improved power generation systems is further, or alternatively, such that issues regarding power distribution, power generation versus changing peak power demands, emissions, barriers to infrastructure development, and challenges and limitations posed by vehicle electrification may each be addressed, improved upon, or alleviated.
Small-scale or portable power generation systems are desirable for applications including space vehicles and systems, automotive drivetrain and aerospace propulsion electrification, direct cooling sources, and portable or distributed power generation such as to address issues regarding power generation efficiency, density, and output. However, there is a need for improved thermal efficiency, electrical conversion efficiency, or both, for such systems.
Heat engines and other devices for converting thermal energy into useful work are generally inefficient relative to their maximum theoretical efficiency. Carnot's theorem states that the maximum theoretical efficiency (ηCarnot) for an ideal, reversible heat engine is given by:
where Thot,engine is the absolute temperature (e.g. in Rankine or Kelvin) at which heat enters the engine and Tcold,ambient is the absolute temperature of the environment into which the engine exhausts its waste heat. Carnot efficiencies for terrestrial applications over 90% and Carnot efficiencies for space applications of over 99% are theoretically possible based at least on known fuel sources. However, in practice, THot,engine is limited by the maximum operating temperature of the materials in the engine and TCold,ambient is limited by an available heat sink available (e.g., the atmosphere at ambient temperature, the temperature of a body of water, etc.). Thus, heat engines may generally operate with a temperature ratio (THot,engine/TCold,ambient) between 2 and 4 and have actual Carnot efficiencies between 50% and 70% (
Achieving maximum theoretical efficiency of a system is challenged or limited based at least on inefficient combustion, inefficient heat exchange, heat losses to a surrounding environment, non-ideal behavior of one or more working fluids, friction losses, pumping losses, or other inefficiencies and imperfections, or energy required to operate the system. Actual or real thermal efficiency ηth,system of a system including a heat engine, heat generation sources, heat removal systems, or other heat exchangers, is given by:
Actual or real thermal efficiency ηth of a heat engine is given by:
where Wout is the net useful work done by the engine, Qin is the thermal energy received by the engine, and Qout is the thermal energy lost or rejected to the environment. Ein is the electrical energy used by the system for operation of the system (e.g., fuel and/or oxidizer pumps, cooling sources, etc.). Win is work input into the system. Achievable thermal efficiency tends to increase with power output. For example, motor vehicle applications are generally 20% to 35% thermally efficient, while large marine and stationary diesel systems can exceed 50% thermal efficiency (
The useful work generated by a heat engine can further be converted into electrical energy. The electrical efficiency (ηEl) can be calculated in the same manner as the thermal efficiency:
where Eout is the net electrical energy output from an electric machine that is operatively coupled to the engine and Qin is the thermal energy received by the engine. Eout may be calculated by subtracting any electricity required to operate the power generation system from the gross power generated by the system. If combustion is the source of heating working fluid for the engine, the electrical efficiency may be calculated using a lower heating value (LHV) of the fuel. Gas turbine power plants have demonstrated greater than 41% LHV electrical efficiency. Stirling engines have demonstrated LHV electrical efficiencies between 10% and 30%.
Waste heat, or an amount of heat from a heat engine that is not converted into useful work, may be recoverable to provide additional benefit before being exhausted. The amount and quality of the recoverable heat varies based on the cycle, the engine (
where Eout,1 is the net electricity produced by a first power generation cycle, Eout,2 is the net electricity produced by a second power generation cycle, Eout,n is the net electricity produced by an nth (final) power generation cycle, and ΣQin is the net thermal energy received by the system. Generally, the net thermal energy received by the system may be nominally Qin of the topping cycle, or additionally or alternatively inclusive of any supplementary thermal input (e.g. supplementary firings, if applicable). Stated another way, ηCC is the total net electricity generated by the entire combined cycle power generation system divided by the total energy input into the combined cycle system. Some combined cycle power generation systems may include an efficiency (i.e., LHV electrical efficiency) of up to approximately 62% for a gas turbine bottomed by a steam cycle.
Waste heat may also be used to produce hot water, process steam, or other useful products that would otherwise require additional energy input to produce in a combined heat and power (CHP) system or cogeneration system, after a combined cycle, or in lieu thereof. The overall electrical efficiency ηCHP of a combined heat and power system is given by:
where Eout is the net useful power output of the system, ΣQth is the sum of the net useful thermal outputs from the system, and Qin is the thermal energy received by the system. CHP systems may have demonstrated total efficiencies between 55% and 85%. CHP systems with Stirling engines may have total efficiencies of 88% and higher. However, higher CHP system efficiencies can come at the cost of lower thermal efficiency, lower electrical efficiency, or both. For example, ηCHP can maximized by maximizing ΣQth, which may be achieved at the cost of electricity generation.
Known closed cycle engines, such as Stirling arrangements, are challenged to produce increasing levels of power output and power density. Such larger sizes or scales can negate other desirable qualities of the engine, such as relatively small-scale or portability. Stirling engines tend to have low power output, with power generation of 1-5 kW for domestic use, up to 25 kW for commercial use, or up to 75 kW for military use. At least one 75 kW engine Stirling engine is a four shaft kinematic Stirling engine for use in submarines. It is nominally 1.1 m in diameter, 1.75 m long, including the generator and control system but not including the fuel or oxidizer sources, with an energy density of 175 kWh/ton.
Stirling engines may generally include two types: kinematic or free piston. Kinematic Stirling engines use mechanically-connected piston assemblies to transmit and convert linear motion of the pistons to a rotary motion for an output shaft. Although such systems may address issues regarding power transmission and stability of the engine, mechanically-connected piston assemblies introduce relatively large power losses via the mechanical members. Additionally, or alternatively, the relatively fixed relationship of mechanically-connected piston assemblies limits the mechanical stroke of the piston assembly. As such, the efficiency of mechanically-connected multi-piston assemblies in a closed cycle engine is decreased in addition to mechanical losses (e.g., friction, leakage, inertia, etc.).
Single-piston free piston closed cycle engine arrangements generally exchange improved thermal efficiency for lower total power generation and density. As such, single-piston free piston closed cycle engine arrangements are not generally suited for higher power output applications.
Multi-piston free piston closed cycle engine arrangements may provide thermal efficiencies of single-piston free piston arrangements and further increase total power generation. However, multi-piston free piston arrangements generally differ from single-piston arrangements and mechanically-connected multi-piston arrangements in that the cycle or motion of a multi-piston free piston arrangement is generally determined by thermo-mechanical interactions of the entire system including the free pistons, the thermal source(s), and a power extraction apparatus. The thermo-mechanical interactions may further include mechanical losses and their effect on balance of the entire system.
For example, multi-piston free-piston closed cycle engines are challenged to respond to time lags. As another example, if one piston assembly drifts from an intended position a subsequent oscillation can become unbalanced. An unbalanced arrangement may lead to undesired vibrations, crashing of the pistons to end walls, or other mechanical losses that may further reduce power output, induce wear and deterioration, or otherwise reduce efficient, stable, or effective use of a multi-piston free piston engine.
As such, there is a need for improved closed cycle engines such as Stirling engines that provide improved power generation efficiency and output. Additionally, there is a need for such improved closed cycle engines that may further retain or improve power density, such as to provide relatively small-scale or portability such as to provide improved application to power generation and distribution systems.
System for Energy Conversion
Referring now to
In various embodiments, the load device C092 is a mechanical work device or an electric machine. In one embodiment, the load device C092 is a pump, compressor, or other work device. In another embodiment, the load device C092 as an electric machine is configured as a generator producing electric energy from movement of a piston assembly A1010 at the engine. In still another embodiment, the electric machine is configured as a motor providing motive force to move or actuate the piston assembly A1010, such as to provide initial movement (e.g., a starter motor). In still various embodiments, the electric machine defines a motor and generator or other electric machine apparatus such as described further herein.
A heater body C100 is thermally coupled to the engine A100. The heater body C100 may generally define any apparatus for producing or otherwise providing a heating working fluid such as to provide thermal energy to the engine working fluid. Various embodiments of the heater body C100 are further provided herein. Exemplary heater bodies C100 may include, but are not limited to, a combustion or detonation assembly, an electric heater, a nuclear energy source, a renewable energy source such as solar power, a fuel cell, a heat recovery system, or as a bottoming cycle to another system. Exemplary heater bodies C100 at which a heat recovery system may be defined include, but are not limited to, industrial waste heat generally, gas or steam turbine waste heat, nuclear waste heat, geothermal energy, decomposition of agricultural or animal waste, molten earth or metal or steel mill gases, industrial drying systems generally or kilns, or fuel cells. The exemplary heater body C100 providing thermal energy to the engine working fluid may include all or part of a combined heat and power cycle, or cogeneration system, or power generation system generally.
In still various embodiments, the heater body C100 is configured to provide thermal energy to the engine working fluid via a heating working fluid. The heating working fluid may be based, at least in part, on heat and liquid, gaseous, or other fluid provided by one or more fuel sources and oxidizer sources providing a fuel and oxidizer. In various embodiments, the fuel includes, but is not limited to, hydrocarbons and hydrocarbon mixtures generally, “wet” gases including a portion of liquid (e.g., humid gas saturated with liquid vapor, multiphase flow with approximately 10% liquid and approximately 90% gas, natural gas mixed with oil, or other liquid and gas combinations, etc.), petroleum or oil (e.g., Arabian Extra Light Crude Oil, Arabian Super Light, Light Crude Oil, Medium Crude Oil, Heavy Crude Oil, Heavy Fuel Oil, etc.), natural gas (e.g., including sour gas), biodiesel condensate or natural gas liquids (e.g., including liquid natural gas (LNG)), dimethyl ether (DME), distillate oil #2 (DO2), ethane (C2), methane, high H2 fuels, fuels including hydrogen blends (e.g., propane, butane, liquefied petroleum gas, naphtha, etc.), diesel, kerosene (e.g., jet fuel, such as, but not limited to, Jet A, Jet A-1, JP1, etc.), alcohols (e.g., methanol, ethanol, etc.), synthesis gas, coke over gas, landfill gases, etc., or combinations thereof.
In various embodiments, the system A10 includes a working fluid body C108, such as further described herein. In one embodiment, the working fluid body C108 defines a hot side heat exchanger A160, such as further described herein, from which thermal energy is output to the engine working fluid at an expansion chamber A221 of the engine. The working fluid body C108 is positioned at the expansion chamber A221 of the engine in thermal communication with the heater body C100. In other embodiments, the working fluid body C108 may be separate from the heater body C100, such that the heating working fluid is provided in thermal communication, or additionally, in fluid communication with the working fluid body C108. In particular embodiments, the working fluid body C108 is positioned in direct thermal communication with the heater body C100 and the expansion chamber A221 of the engine A100 such as to receive thermal energy from the heater body C100 and provide thermal energy to the engine working fluid within the engine.
In still various embodiments, the heater body C100 may include a single thermal energy output source to a single expansion chamber A221 of the engine. As such, the system A10 may include a plurality of heater assemblies each providing thermal energy to the engine working fluid at each expansion chamber A221. In other embodiments, such as depicted in regard to
The system A10 further includes a chiller assembly, such as chiller assembly A40 further described herein. The chiller assembly A40 is configured to receive and displace thermal energy from a compression chamber A222 of the engine. The system A10 includes a cold side heat exchanger A42 thermally coupled to the compression chamber A222 of the closed cycle engine and the chiller assembly. In one embodiment, the cold side heat exchanger A42 and the piston body C700 defining the compression chamber A222 of the engine are together defined as an integral, unitary structure, such as further shown and described in regard to
In various embodiments, the chiller assembly A40 is a bottoming cycle to the engine A100. As such, the chiller assembly A40 is configured to receive thermal energy from the engine A100. The thermal energy received at the chiller assembly A40, such as through a cold side heat exchanger A42, or cold side heat exchanger A170 further herein, from the engine A100 is added to a chiller working fluid at the chiller assembly A40. In various embodiments, the chiller assembly A40 defines a Rankine cycle system through which the chiller working fluid flows in closed loop arrangement with a compressor. In some embodiments, the chiller working fluid is further in closed loop arrangement with an expander. In still various embodiments, the system A10 includes a heat exchanger A88 (
Referring still to
As further described herein, in various embodiments the chiller assembly A40 may include a substantially constant density heat exchanger. The constant density heat exchanger generally includes a chamber including an inlet and an outlet each configured to contain or trap a portion of the chiller working fluid for a period of time as heat from the closed cycle engine is transferred to the cold side heat exchanger A42. In various embodiments, the chamber may define a linear or rotary chamber at which the inlet and the outlet are periodically opened and closed via valves or ports such as to trap the chiller working fluid within the chamber for the desired amount of time. In still various embodiments, the rate at which the inlet and the outlet of the chamber defining the constant density heat exchanger is a function at least of velocity of a particle of fluid trapped within the chamber between the inlet and the outlet. The chiller assembly A40 including the constant density heat exchanger may provide efficiencies, or efficiency increases, performances, power densities, etc. at the system A10 such as further described herein.
It should be appreciated that in other embodiments, the chiller assembly A40 of the system A10 may include a thermal energy sink generally. For example, the chiller assembly A40 may include a body of water, the vacuum of space, ambient air, liquid metal, inert gas, etc. In still various embodiments, the chiller working fluid at the chiller assembly A40 may include, but is not limited to, compressed air, water or water-based solutions, oil or oil-based solutions, or refrigerants, including, but not limited to, class 1, class 2, or class 3 refrigerants. Further exemplary refrigerants may include, but are not limited to, a supercritical fluid including, but not limited to, carbon dioxide, water, methane, ethane, propane, ethylene, propylene, methanol, ethanol, acetone, or nitrous oxide, or combinations thereof. Still exemplary refrigerants may include, but are not limited to, halon, perchloroolefin, perchlorocarbon, perfluoroolefin, perfluororcarbon, hydroolefin, hydrocarbon, hydrochloroolefin, hydrochlorocarbon, hydrofluoroolefin, hydrofluorocarbon, hydrochloroolefin, hydrochlorofluorocarbon, chlorofluoroolefin, or chlorofluorocarbon type refrigerants, or combinations thereof. Still further exemplary embodiments of refrigerant may include, but are not limited to, methylamine, ethylamine, hydrogen, helium, ammonia, water, neon, nitrogen, air, oxygen, argon, sulfur dioxide, carbon dioxide, nitrous oxide, or krypton, or combinations thereof.
It should be appreciated that where combustible or flammable refrigerants are included for the chiller working fluid, various embodiments of the system A10 may beneficially couple the heater body C100, and/or the fuel source, and the chiller assembly A40 in fluid communication such that the combustible or flammable working fluid to which thermal energy is provided at the chiller assembly A40 may further be utilized as the fuel source for generating heating working fluid, and the thermal energy therewith, to output from the heater body C100 to the engine working fluid at the engine A100.
Various embodiments of the system A10 include control systems and methods of controlling various sub-systems disclosed herein, such as, but not limited to, the fuel source, the oxidizer source, the cooling fluid source, the heater body C100, the chiller assembly C40, the engine A100, and the load device C092, including any flow rates, pressures, temperatures, loads, discharges, frequencies, amplitudes, or other suitable control properties associated with the system A10. In one aspect, a control system for the system A10 defining a power generation system is provided. The power generation system includes one or more closed cycle engines (such as engine A100), one or more load devices defining electric machines (such as load device C092) operatively coupled to the engine, and one or more energy storage devices in communication with the electric machines.
The control system can control the closed cycle engine and its associated balance of plant to generate a temperature differential, such as a temperature differential at the engine working fluid relative to the heating working fluid and the chiller working fluid. Thus, the engine defines a hot side, such as at the expansion chamber A221, and a cold side, such as at the compression chamber A222. The temperature differential causes free piston assemblies A1010 to move within their respective piston chambers defined at respective piston bodies C700. The movement of the pistons A1011 causes the electric machines to generate electrical power. The generated electrical power can be provided to the energy storage devices for charging thereof. The control system monitors one or more operating parameters associated with the closed cycle engine, such as piston movement (e.g., amplitude and position), as well as one or more operating parameters associated with the electric machine, such as voltage or electric current. Based on such parameters, the control system generates control commands that are provided to one or more controllable devices of the system A10. The controllable devices execute control actions in accordance with the control commands. Accordingly, the desired output of the system A10 can be achieved.
Furthermore, the control system can monitor and anticipate load changes on the electric machines and can control the engine A100 to anticipate such load changes to better maintain steady state operation despite dynamic and sometimes significant electrical load changes on the electric machines. A method of controlling the power generation system is also provided. In another aspect, a control system for a heat pump system is provided. The heat pump system includes one or more of the closed cycle engines described herein. A method of controlling the heat pump system is also provided. The power generation and heat pump systems as well as control methods therefore are provided in detail herein.
Energy Conversion Apparatus
Referring now to
In various embodiments, the piston assembly A1010 defines a double-ended piston assembly A1010 in which a pair of pistons A1011 is each coupled to a connection member A1030. The connection member A1030 may generally define a rigid shaft or rod extended along a direction of motion of the piston assembly A1010. In other embodiments, the connection members A1030 includes one or more springs or spring assemblies, such as further provided herein, providing flexible or non-rigid movement of the connection member A1030. In still other embodiments, the connection member A1030 may further define substantially U- or V-connections between the pair of pistons A1011.
Each piston A1011 is positioned within the piston body C700 such as to define the expansion chamber A221 and the compression chamber A222 within the volume of the piston body C700. The load device c092 is operably coupled to the piston assembly A1010 such as to extract energy therefrom, provide energy thereto, or both. The load device c092 defining an electric machine is in magnetic communication with the closed cycle engine via the connection member A1030. In various embodiments, the piston assembly A1010 includes a dynamic member A181 positioned in operable communication with a stator assembly A182 of the electric machine. The stator assembly A182 may generally include a plurality of windings wrapped circumferentially relative to the piston assembly A1010 and extended along a lateral direction L. In one embodiment, such as depicted in regard to
Referring to
The engine A100 defines an outer end A103 and an inner end A104 each relative to a lateral direction L. The outer ends A103 define laterally distal ends of the engine A100 and the inner ends 104 define laterally inward or central positions of the engine A100. In one embodiment, such as depicted in regard to
The chiller assembly A40 is positioned in thermal communication with each compression chamber A222. Referring to
In various embodiments, such as depicted in regard to
Engine Chamber to Chamber Conduits Arrangements
The cross sectional view provided in
Referring to
The engine A100 further includes a plurality of walled conduits A1050 connecting particular chambers A221, A222 of each piston body C700 (
In various embodiments, the interconnected volume includes pairs of the expansion chamber A221 fluidly coupled to the compression chamber A222 each defined at laterally separated ends of the piston assemblies A1010. In one embodiment, the engine A100 defines a first end 101 separated along the lateral direction L by the connection member A1030 from a second end 102, such as depicted in
To provide a balanced pressure arrangement of piston assemblies A1010, one interconnected volume includes a pair of the expansion chamber A221 at one end (e.g., the first end 101 or the second end 102) connected to the compression chamber A222 at the other or opposite end. In one embodiment, the expansion chamber A221 at the first end 101 is fluidly connected to the compression chamber A222 at the second end 102. In another embodiment, the expansion chamber A221 at the second end 102 is fluidly connected to the compression chamber A222 at the first end 101. The interconnected volume further includes a pair of expansion chambers A221 at the first end 101 or the second end 102 connected to a respective compression chamber A222 at the same end, opposing ends, or both, relative to the expansion chamber A221. In one embodiment, the expansion chamber A221 at the first end 101 is fluidly connected to the compression chamber A222 at the same end (i.e., the first end 101). In another embodiment, the expansion chamber A221 at the second end 102 is fluid connected to the compression chamber A222 at the same end (i.e., the second end 102). In yet another embodiment, the expansion chamber A221 at the first end 101 is fluidly connected to the compression chamber A222 at the second end 102 (i.e., the opposing end). In still yet another embodiment, the expansion chamber A221 at the second end 102 is fluidly connected to the compression chamber at the first end 101 (i.e., the opposing end). It should be appreciated that the arrangement described herein includes each expansion chamber A221 of one piston body C700 of one piston assembly A1010 connected to a respective compression chamber A222 of another, different piston body C700 of another, different piston assembly A1010. It should further be appreciated that, in various embodiments, the expansion chamber A221 of one piston body C700 and one piston assembly C1010 is exclusively fluidly connected to the compression chamber A222 of another piston body C700 of another piston assembly C1010 (i.e., each walled conduit A1050 fluidly connects only one expansion chamber A221 to only one compression chamber A222).
The balanced pressure arrangement of piston assemblies A1010 described herein is such that a uniform temperature applied at the expansion chambers A221 and the compression chambers A222 provides an equal pressure at the expansion chamber A221 of one piston body C700 counteracted by an equal and opposite pressure at the same piston body C700 relative to the expansion chamber A221. Stated alternatively, when a uniform temperature is applied to the expansion chambers A221 and the compression chambers A222, movement of one piston assembly A1010 defining a free piston assembly A1010 results in pressure cancellation at adjacent piston assemblies A1010 such that pressure waves will not propagate to induce movement of the adjacent piston assembly A1010.
It should be appreciated that each interconnected volume described herein includes one or more passages, chambers, openings, or other flowpaths between the arrangements of the compression chamber A222 and the expansion chamber A221 described above. For example, the particular arrangements of walled conduits A1050 providing fluid communication of the engine working fluid between the compression chamber A222 and the expansion chamber A221 such as described in regard to
Although depicted as a balanced pressure arrangement of four piston assemblies A1010 at eight piston bodies C700 defining eight fluidly connected pairs of expansion chambers A221 and compression chambers A222, it should be appreciated that the engine A100 generally includes an interconnected volume such as described above. As such, other embodiments of the engine A100 may include a quantity of two or more piston assemblies A1010 in which the arrangements of the piston assembly A1010 are scaled accordingly based on the arrangement described above such as to provide at least one interconnected volume of chambers A221, A222 and conduits 1050.
In various embodiments, the system A10 defines the reference longitudinal axis C204 extended co-directional to the lateral direction L or generally along a direction along which the pistons A1011 articulate within the chambers A221, A222. The chambers A221, A222 are positioned in circumferential arrangement relative to the reference longitudinal axis C204. Each chamber 221, 222 is extended along the lateral direction L or otherwise co-directional to the reference longitudinal axis C204.
In one embodiment, the engine includes four piston assemblies A1010 extended along the lateral direction L and in circumferential arrangement relative to the reference longitudinal axis C204. The piston assemblies A1010 may be positioned equidistant to one another around the reference longitudinal axis C204. In one embodiment, a pair of the heater body is positioned at outer ends A103 of the engine. The heater body is positioned proximate to the expansion chamber A221 and distal to the compression chamber A222. Each heater body may be positioned and configured to provide a substantially even flow of thermal energy to four hot side heat exchangers 160 or expansion chambers A221 at a time.
In other embodiments, the engine A100 includes two or more piston assemblies A1010 in side-by-side arrangement. The piston assemblies A1010 may be positioned equidistant relative to one another. In still various embodiments, a single heater body C100 may be positioned relative to each hot side heat exchanger or working fluid body C108. It should be appreciated that various embodiments of the system A10 provided herein may include any quantity of heater bodies positioned at any quantity of expansion chambers A221 as desired. Further embodiments of the system A10 provided herein in regard to
It should further be appreciated that although the piston assemblies A1010 of the engine A100 are depicted in straight, flat, inline, or horizontally opposed arrangements, the piston assemblies A1010 and heater bodies C100 may alternatively be arranged in V-, W-, radial, or circumferential arrangements, or other suitable piston assembly A1010 arrangements. For example, one or more embodiments of the system A10 may include a center and/or outer heater body C100 around which the plurality of piston assemblies A1010 is positioned.
Referring now to
In
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Regarding
Referring to
It should be appreciated that various embodiments of the system A10 provided in regard to
Referring now to
In general, the exemplary embodiments of system A10 and engine, or portions thereof, described herein may be manufactured or formed using any suitable process. However, in accordance with several aspects of the present subject matter, some or all of system A10 may be formed using an additive manufacturing process, such as a 3-D printing process. The use of such a process may allow portions of the system A10 to be formed integrally, as a single monolithic component, or as any suitable number of sub-components. In various embodiments, the manufacturing process may allow the all or part of the heater body, the chiller assembly, the load device c092, or the engine to be integrally formed and include a variety of features not possible when using prior manufacturing methods. For example, the additive manufacturing methods described herein provide the manufacture of the system A10 having unique features, configurations, thicknesses, materials, densities, and structures not possible using prior manufacturing methods. Some of these novel features can, for example, improve thermal energy transfer between two or more components, improve thermal energy transfer to the engine working fluid, improve thermal energy transfer from the engine working fluid to the chiller working fluid, reduce leakages, or facilitate assembly, or generally improve thermal efficiency, power generation and output, or power density of the system A10 using an additive manufacturing process as described herein.
Balanced Phase and/or Balanced Pressure Closed-Cycle Engine Arrangements
Pressure Wave Disruption
Embodiments of a multi-piston engine apparatus A100 provided herein show and describe a balanced pressure piston engine containing an engine working fluid. Certain embodiments of the engine shown and described herein provide dynamic stability in amplitude, frequency, or both. Various embodiments of the apparatus further provide for power to be modulated by piston stroke via a free piston assembly arrangement as a passively balanced system during operation. As such, the engine provided herein may operate in balanced pressure or balanced phase arrangement without control systems or mechanical linkages between piston assemblies, such as camshafts, crankshafts, etc. Other embodiments provide for balanced pressure arrangement with force transmission linkages coupling piston assemblies with minimal power losses. Certain embodiments of the engine provided herein mitigate or disrupt propagation of pressure waves that may disrupt an intended motion (dynamic stability in amplitude, frequency, phase, center point of oscillation or all of these) of a plurality of pistons in a closed cycle engine arrangement such as a Stirling engine generally. The embodiments of the engine provided herein include a closed cycle piston engine arrangement including a plurality of chambers in particular fluid connection such as to provide pneumatic isolation or force cancellation at adjacent chambers when the engine working fluid is at a uniform temperature at the plurality of chambers.
Closed cycle engine arrangements generally include a plurality of pistons defining an expansion chamber and a compression chamber, or a hot chamber and a relatively cold chamber, defined by a piston within a cylinder. Such closed cycle engine arrangements may include, but are not limited to, a Stirling engine assembly, or variations thereof, such as, alpha, beta, or gamma Stirling configurations, or other variations, such as, but not limited to, a Vuilleumier, Franchot, or Rinian engine arrangement. Certain configurations, such as beta and gamma configurations, further include a displacer piston in contact with the hot chamber and the cold chamber and a power piston in contact with the cold chamber. Further configurations, such as a Vuilleumier arrangement, include a warm chamber in which one piston is in contact with the hot chamber and the warm chamber and another piston is in contact with the cold chamber and the warm chamber. However, configurations including the warm chamber are generally counter-productive to providing improved power density, as the warm chamber is used to improve operation of the engine but decreases power generation per unit volume of working fluid.
In other configurations including a hot chamber and a cold chamber, or in various configurations, additionally a warm chamber, undesired creation and propagation of pressure waves may occur across fluidly connected chambers. Such pressure propagation may inhibit operation of the engine at transient conditions, such as via undesired harmonics or vibrations that cause undesired operation or unacceptable power losses. Pressure propagation may further, or alternatively, cause undesired phase-shift, undesired changes in amplitude, or run-away behavior of the pistons relative to one another, such as to result in undesired operation of the engine.
For example, in certain free piston Stirling engine arrangements, serial or consecutive coupling of a compression chamber at one reciprocating piston to an adjacent or serially consecutive expansion chamber of another reciprocating piston, and further connected in a loop to the first reciprocating piston, provide a change in pressure in one chamber to induce movement of the piston in contact with the chamber. Such change in pressure in one chamber inducing movement of the piston in contact with the chamber may further occur even in the absence of a thermal load, such as a thermally-driven expansion and contraction of a volume of fluid. As such, a change in pressure results in the other chamber defined by the same piston (i.e., the chamber defined on an opposite side of the same piston). The change in pressure produces a pressure wave and corresponding force that is allowed to propagate to each adjacent or serially consecutive fluidly coupled chamber and the associated piston at the fluidly coupled chamber. The pressure wave propagation is allowed to repeat, or may repeat indefinitely, through the plurality of fluidly coupled chambers and associated pistons of the engine. The pressure wave and corresponding force may subsequently propagate through the serially coupled chambers back to the first reciprocating piston. The pressure wave propagation may therefore create harmonic waves and disrupt an intended motion (e.g., frequency, amplitude, and/or phase, or combinations thereof), or an intended center-point of motion in a multi-piston arrangement, or both.
Additionally, or alternatively, the pressure wave propagation means that movement of one reciprocating piston induces movement of each adjacent piston of the fluidly connected chambers. As such, pressure wave propagation may cause movement of adjacent pistons within the fluidly connected arrangement of chambers. The pressure wave propagation across fluidly connected chambers results in the pistons being articulated, at least in part, by mechanical forces (i.e., pressure waves and their corresponding forces) rather than via thermal differences between the hot chamber and the cold chamber.
Pressure wave propagations may further adversely affect double acting piston assemblies, or particularly double acting free piston assemblies. For example, the fluidly connected arrangement of chambers may be arranged such that pistons at one end of a piston assembly include one fluidly coupled arrangement of chambers and pistons at another end of the piston assembly include another fluidly coupled arrangement of chambers. However, the fluidly coupled arrangements may allow pressure wave propagations to cause movement of one piston assembly due to movement of another piston assembly even with uniform temperatures at the chambers. Stated differently, fluidly connected arrangements of piston assemblies allow mechanical forces (i.e., pressure propagation) to induce movement of adjacent piston assemblies rather than thermal differences between the chambers.
In certain instances, such pressure wave propagation may cause the affected piston to displace to an extreme position, such as top dead center (TDC) or bottom dead center (BDC). Displacement to the extreme position may cause the piston to contact or crash into the extreme end of the surrounding cylinder, such as to damage the piston or cylinder or otherwise adversely affect power output, stability, or operation of the engine. As another example, pressure wave propagation inducing movement of adjacent pistons via mechanical forces may result in unbalanced phase movement of the pistons relative to one another, which may result in undesired operation. Pressure wave propagation may generally result in undesired operation of the engine such as to cause undesired power losses, damage, vibrations, or other losses to power output or operability.
In still other examples, Stirling engines, or variations thereof, may include fluid coupling of expansion and compression chambers such as to result in a force acting on a piston along its direction of motion. Such examples promote self-starting, such as to reduce input power necessary for starting the engine. However, such self-starting behavior may result from or provide pressure wave propagation during operation of the engine, such as to result in undesired operation of the engine as described above.
Referring to
Additionally, or alternatively, embodiments of the apparatus A100 provided herein may beneficially provide balanced pressure arrangement of a plurality of piston assemblies A1010 during operation of the apparatus. The balanced pressure arrangement operation of the apparatus A100 may be identified by the stationary behavior of one piston assembly following articulation or actuation of another piston assembly when the engine working fluid is at a substantially uniform temperature in the apparatus A100. The apparatus A100 may provide the stationary behavior of the piston assembly via substantially equal and opposite forces produced at an adjacent piston assembly following articulation of another piston assembly.
Embodiments of the apparatus A100 may beneficially improve overall stability, balance, power output, and operability of the apparatus via the balanced pressure arrangements provided herein. Additionally, various embodiments of the apparatus A100 may beneficially improve overall operation of piston engine assemblies, such as closed cycle engine assemblies, despite detriments that may be associated with production of substantially equal and opposite forces at an adjacent piston assembly. For example, embodiments of the apparatus A100 provided herein may include beneficial improvements to overall operation greater than losses associated with starting the apparatus A100. As another example, the substantially equal and opposite forces at an adjacent piston assembly may increase a threshold input power required to initialize operation of the piston assemblies (i.e., articulation of the piston assemblies), such as to require a greater input torque or power at the piston assembly to overcome greater counteracting forces, inertia, etc. However, in contrast, operation of the piston assemblies thereafter may include improved stability, power output, reduced vibrations, mitigated risk of damage or other losses to power or operability.
Referring to
The piston A1011 of the piston assembly A1010 is surrounded by a piston body A1020. The piston body A1020 defines at least one of a first chamber A221 or a second chamber A222. In various embodiments, the piston body A1020 defines at one side (e.g., a first side A1025 depicted in
In various embodiments, the portion of the plurality of walled conduits A1050 fluidly connects the first chamber A221 of one piston assembly and the second chamber A222 of another piston assembly into an interconnected volume A300. The interconnected volume A300 defines a fluid interconnection of the first chamber A221 and the second chamber A222 at different piston assemblies A1010 such that a fluid communication or fluid leakage path between the first chamber A221 and the second chamber A222 of the same piston A1011 provides a single fluid loop separated from the fluidly connected chambers A221, A222 outside of the interconnected volume A300. In one embodiment, the balanced pressure arrangement and/or the balance phase arrangement of the piston assemblies A1010 is the fluid interconnection of the walled conduits A1050 and chambers A221, A222 such that the chambers A221, A222 within the interconnected volume A300 are substantially fluidly separated and/or pneumatically separated from those chambers A221, A222 outside of the interconnected volume A300 to provide a substantially equal and opposite force relative to one another to at least one piston assembly A1010 when the engine working fluid within the chambers A221, A222 is at a uniform temperature. In various embodiments, the apparatus A100 includes a plurality of interconnected volumes A300, such as a first interconnected volume A301 fluidly separated and pneumatically separated from a second interconnected volume A302.
In one embodiment, the plurality of piston assemblies A1010 includes a first piston assembly A1110 fluidly coupled to a second piston assembly A1210 via the walled conduit A1050. The first chamber A221 and the second chamber A222 each define a spring, such as a gas spring (i.e., a spring-mass system in which the gas spring is at least in part the engine working fluid, such as helium, hydrogen, or air, or another suitable working fluid). The first chamber A221 at the first piston assembly A1110 is fluidly coupled to the second chamber A222 at the second piston assembly A1210 in balanced pressure arrangement, i.e., at substantially uniform temperatures relative to the first chamber A221 and the second chamber A222, movement of the first piston assembly A1110 provides substantially equal and opposite force at the piston A1011 or connection member A1030 of another piston assembly (e.g., the second piston assembly A1210) such as to result in a substantially zero net force, such as depicted via signs + or − in
In various embodiments, the first chamber A221 and the second chamber A222 each define the spring as a gas spring based at least on the fluid coupling of the first chamber A221 of the first piston assembly A1110 to the second chamber A222 of the second piston assembly A1210 to include at least two interconnected volumes A301, A302 fluidly and/or pneumatically separated from one another (i.e., balanced pressure arrangement). In one embodiment, the at least two interconnected volumes includes the first interconnected volume A301 substantially fluidly isolated and pneumatically isolated from the second interconnected volume A302.
The arrangement of the interconnected volume A300, or plurality thereof, mitigates pressure propagation across the plurality of piston assemblies A1010 such that movement of adjacent piston assemblies is not driven by mechanical forces. Stated differently, the arrangement of the chambers A221, A222 within the interconnected volume A300 relative to chambers outside of the interconnected volume A300 provides for movement of one piston assembly of the interconnected volume A300 to induce an equal and opposite force at an adjacent piston assembly in fluid contact with the piston assembly A1010 outside of the interconnected volume A300. Alternatively, the arrangement of chambers A221, A222 within the first interconnected volume A301 relative to chambers within the second interconnected volume A302 provides for movement of one piston assembly at one interconnected volume to induce an equal and opposite force at an adjacent piston assembly at another interconnected volume.
In various embodiments, the adjacent or second piston assembly A1210 is in fluid contact with the interconnected volume A300 and outside thereof. In another embodiment, the second piston assembly A1210 is in fluid contact with the first interconnected volume A301 and the second interconnected volume, and the first piston assembly A1110 is in fluid contact with only the interconnected volume A300, such as either the first interconnected volume or the second interconnected volume A302. As such, when the first chamber A221 and the second chamber A222 are each at uniform temperature conditions, mechanical movement of one piston assembly will not induce movement of another piston assembly. Still further, when the first chamber A221 and the second chamber A222 are at a temperature differential or delta temperature relative to one another, such as to define a hot chamber and a cold chamber respectively, movement of the piston assemblies is substantially only via the temperature differential rather than mechanical forces such as pressure wave propagation.
In various embodiments, a method for operating a balanced pressure piston apparatus, such as the apparatus A100 provided herein, is provided. In still various embodiments, a method for balancing a piston apparatus is provided. In still various embodiments, a method for balanced pressure operation of the piston apparatus is provided. The method includes flowing a first portion of the engine working fluid through a first plurality of interconnected chambers including a first chamber on the first end of a first piston assembly and a second chamber on the second end of a second piston assembly. Flowing the first portion of engine working fluid may include flowing the first portion of engine working fluid within a fluidly interconnected volume (e.g., interconnected volume 301 in
In particular embodiments, the method further includes at flowing a second portion of the engine working fluid through a second plurality of chambers, in which the first portion of the engine working fluid is fluidly separated from the second portion of the engine working fluid. In various embodiments, the second portion of the engine working fluid may be defined in a second interconnected volume of chambers (e.g., interconnected volume 302 in
In various embodiments, the method further includes receiving, at the engine working fluid at the first chamber A221 and the second chamber A222, a substantially uniform temperature. A first pressure is generated at the first chamber A221 of one assembly by moving or otherwise articulating one or more piston assemblies along a first direction while the engine working fluid is at a substantially uniform temperature at the first chamber A221 and the second chamber A222 (e.g., a first lateral direction co-directional to extension of the piston within the piston body, or a first circumferential direction co-directional to extension of the piston within the piston body). In various embodiments, articulating the one or more piston assemblies includes moving, articulating, or actuating the first piston assembly A1110. A second pressure at the first chamber A221 of another piston assembly, such as the second piston assembly A1210, is also generated by articulating the one piston assembly (e.g., the first piston assembly A1110). The second pressure and the first pressure together generate a substantially zero net force at the other piston assembly (e.g., the second piston assembly A1210) such that the other piston assembly (e.g., the second piston assembly A1210) is stationary when the first piston assembly is articulated in the first direction.
Stated differently, forces induced at the second piston assembly via the second pressure are equal and opposite of the forces induced by the first piston assembly via the first pressure. As such, the second piston assembly remains stationary when the first piston assembly is articulated in the first direction when the engine working fluid at the first chamber and the second chamber is at a uniform temperature relative to one another. Generally, the second piston assembly remains stationary when the first piston assembly is articulated in the first direction when the engine working fluid within the apparatus A100 is at a uniform temperature.
In another embodiment, the method of operating the apparatus includes moving or otherwise articulating the piston assemblies A1010 in a balanced phase relationship relative to one another while the working fluid is at a temperature differential at the working fluid relative to the first chamber A221 and the second chamber A222. Articulating the piston assemblies A1010 may include starting one or more of the first piston assembly A1110 via a starter motor, mechanical power input, or other starter device. Articulating the piston assemblies in balanced phase relationship may further include articulating the plurality of piston assemblies in balanced phase relationship when the temperature differential is applied at the engine working fluid at the first chamber versus the second chamber.
In yet another embodiment, the method further includes applying a motive force at the piston assembly greater than a threshold necessary to overcome counteracting forces at the piston assembly. In various embodiments, the threshold corresponds to friction, inertia, or other forces preventing movement of the piston assembly via the temperature differential. For example, the other forces preventing movement may include, at least in part, equal and opposite forces resulting from the balanced pressure arrangement of the piston assemblies. As such, the arrangement of piston assemblies A1010 may provide the balanced pressure and/or balanced phase relationship of the apparatus A100 and may further require a greater motive force to articulate the piston assembly A1010 during start-up from rest or non-operation.
It should be appreciated that the phase angle of the balanced phase arrangement may depend at least in part on the quantity of the plurality of piston assemblies A1010 of the apparatus A100. In various embodiments, the phase angle between four piston assemblies, or factors thereof, A1010 is approximately 90 degrees, 180 degrees, or 270 degrees. In another embodiment, the phase angle between three piston assemblies A1010, or factors thereof, is approximately 30 degrees, 60 degrees or 120 degrees. In yet another embodiment, the phase angle between five piston assemblies A1010, or factors thereof, is approximately 72 degrees.
In still various embodiments, the apparatus A100 includes a plurality of piston assemblies A1010 in which each piston assembly A1010 defines a first end A101 separated from a second end A102 (e.g., separated along a lateral direction L co-directional to extension or displacement of a piston A1011 of the piston assembly A1010). A pair of pistons A1011 is each connected at the first end A101 and the second end A102. In various embodiments, the pair of pistons A1011 is each connected via the connection member A1030 extended to separate each piston A1011 such as to dispose one piston A1011 at the first end A101 and another piston A1011 at the second end A102. The piston body A1020 surrounds the piston A1011 and defines the first chamber A221 and the second chamber A222 each separated by the piston A1011 at each piston assembly A1010. The plurality of walled conduits A1050 fluidly connects the first chamber A221 at one piston assembly A1010 to the second chamber A222 at another piston assembly A1010. The plurality of walled conduits A1050 fluidly connects the chambers to define at least two interconnected volumes A300 of chambers A221, A222 and walled conduits A1050. Each interconnected volume A300, such as depicted at first interconnected volume A301 and second interconnected volume A302, is fluidly separated from one another. Each interconnected volume A301, A302 is further fluidly separated and/or pneumatically separated from one another. The plurality of piston assemblies A1010 are in balanced pressure arrangement via the plurality of interconnected volumes A300.
The fluidly separated and/or pneumatically separated or isolated interconnected volume A300 includes a pair of the first chamber A221 at the one end fluidly connected to a respective second chamber A222 at the other end. In one embodiment, each interconnected volume A300 includes the first chamber A221 at the first end A101 fluidly connected to a respective second chamber A222 at the second end A102. In another embodiment, the interconnected volume A300 includes the first chamber A221 at the second end A102 fluidly connected to a respective second chamber A222 at the first end A101. As such, the interconnected volume A300 further provides a substantially net zero force at the piston assembly A1010 such as described above.
The fluidly separated and/or pneumatically separated interconnected volume A300 further includes at least two pair of the first chamber A221 at the first end A101 or the second end A102 is each fluidly connected to a respective second chamber A222 at the same end. In one embodiment, at least two pair of the first chamber A221 at the first end A101 is each fluidly connected to a respective second chamber A222 at the first end A101. In another embodiment, at least two pair of the first chamber A221 at the second end A102 is each fluidly connected to a respective second chamber A222 at the second end A102. In still another embodiment, at least four pair of the first chamber A221 at one end is each fluidly connected to a respective second chamber A222 at the same end.
The interconnected volume A300 further includes the first piston assembly A1110 entirely within the interconnected volume. The interconnected volume A300 further includes the second piston assembly A1210 in which one end or pair of hot chamber and cold chamber (e.g., at the first end A101) is within one interconnected volume (e.g., the first interconnected volume A301) and the other end or pair of hot chamber and cold chamber (e.g., at the second end A102) is outside of the interconnected volume or within another interconnected volume (e.g., the second interconnected volume A302). As such, the balanced pressure arrangement mitigates pressure wave propagation at the second piston assembly, such as depicted at arrows A150, when an equal and opposite force is applied to the second piston assembly.
In one embodiment, the interconnected volume A300 fluidly and/or pneumatically separated from other chambers and walled conduits in balanced pressure arrangement each include a hot chamber (i.e., a first chamber) of one piston assembly fluidly connected to a respective cold chamber (i.e., a second chamber) of another piston assembly (i.e., each hot chamber is fluidly connected to the respective cold chamber at the piston assembly different from the hot chamber). The interconnected volume includes a first hot chamber (i.e., a first-first chamber) at the first end fluidly connected to a respective cold chamber (i.e., a second chamber) at the second end. The engine further includes a second hot chamber (i.e., a second-first chamber) at the second end fluidly connected to a respective cold chamber at the first end. Two or more other hot chambers (i.e., first chambers other than the first-first chamber and the second-first chamber) at one end are each fluidly connected to respective cold chambers at the same end.
In one embodiment, a third hot chamber (i.e., a third-first chamber) at the one end, such as the first end, is fluidly connected to a respective cold chamber at the same end, such as the first end. In another embodiment, the third hot chamber at one end, such as the second end, is fluidly connected to a respective cold chamber at the same end, such as the second end. In still another embodiment, a fourth hot chamber (i.e., a fourth-first chamber) at the same end as the third hot chamber, such as either the first end or the second end, is fluidly connected to a respective cold chamber at the same end. In another embodiment, the fourth hot chamber at the other end relative to the third chamber is fluidly connected to a respective cold chamber at the same end (i.e., the other end relative to the third chamber).
Referring now to
Referring still to
The second interconnected volume A302 includes a pair of the hot chambers at one end each fluidly connected to a respective cold chamber at the other end. For example, hot chamber A121 at the first end A101 is fluidly coupled to the cold chamber A128 at the second end A102. Additionally, the hot chamber A127 at the second end A102 is fluidly coupled to the cold chamber A122 at the first end A101. The second interconnected volume A302 further includes a piston assembly entirely (i.e., first piston assembly A1110 of
The apparatus A100 further includes a piston assembly in which the piston body at one end is pneumatically coupled to one interconnected volume and the piston body at the other end is pneumatically coupled to another interconnected volume (i.e., second piston assembly A1210 of
Referring to
At the second piston assembly A1210 at which one pair of hot chamber and cold chamber is included in the first interconnected volume A301 and another pair of hot chamber and cold chamber is included at the second interconnected volume A302 (such as depicted at piston assembly A210, A410 of
Referring now to
In
In
In
In
In various embodiments, the apparatus A100 may be configured to operate a portion of the plurality of piston assemblies A1010 while another portion, such as the remainder of the piston assemblies, remain substantially stationary. In one embodiment, the apparatus A100 may be configured to receive and/or transfer thermal energy at a portion of the piston assemblies A1010 sufficient to articulate the piston assemblies A1010 while another portion of the piston assemblies receives and/or transfers an insufficient amount of thermal energy to sustain operation of another portion of the piston assemblies. For example, the other portion of piston assemblies may define zero thermal difference between the first chamber A221 and the second chamber A222. As another example, a thermal difference between the first chamber A221 and the second chamber A222 may be below a threshold temperature difference such as to be too low to sustain movement of the piston assembly. Operation of a portion of the plurality of piston assemblies A1010 may be provided by disruption of the pressure wave propagation via the interconnected volume A300. As such, a portion of the plurality of piston assemblies A1010 may be disabled from operation based on a desired output power to a load device A180 (
Referring to
Although the expansion chamber or first chamber A221 is generally depicted at the outer end A103 and the compression chamber or second chamber A222 is generally depicted at the inner end A104, it should be appreciated that in other embodiments the first chamber A221 may be positioned at the inner end A104 and the second chamber A222 may be positioned at the outer end A103. It should further be appreciated that a heater assembly, thermal energy input source, or hot side heat exchanger A160 may be positioned at the outer end A103 or the inner end A104 based at least on the positioning of the first chamber A221. It should also be appreciated that a chiller assembly, thermal energy removal source, or cold side heat exchanger A170 may be positioned at the inner end A104 or the outer end A103 based at least on the positioning of the second chamber A222.
In still further embodiments, although certain quantities of the piston assembly A1010 are depicted in
Piston, Valve Assembly, Fluid Bearing, and Flexible Diaphragm
Referring now to
In various embodiments, the thermal energy input source or hot side heat exchanger A160 and the thermal energy removal source or cold side heat exchanger A170 may each define heat exchangers configured to provide (i.e., as the thermal energy input source A160) or extract (i.e., as the thermal energy removal source A170) thermal energy from the engine working fluid from the respective fluid volumes. In another embodiment, the thermal energy input source A160 may define, at least in part, any suitable device providing thermal energy to the first chamber A221, such as, but not limited to, a combustion chamber, an electric or induction heater, a heat engine, or other heater assembly or thermal energy input source. In still another embodiment, the thermal energy removal source A170 may define a cooler, refrigeration unit, bottoming cycle system, or cryogenic system. In various embodiments, the thermal energy input source A160 defines a system from which thermal energy is provided to the first chamber A221 (such as schematically depicted via arrows A161) and the thermal energy output source A170 defines a system to which thermal energy flows from the second chamber A222 (such as schematically depicted via arrows A171).
Referring now to
In another embodiment, the barrier structure A1114 defines, at least in part, a flexible structure, such as a flexible membrane, allowing one or more of the localized fluid chambers A221, A222 within the piston body A1020 to expand and contract, or increase and decrease, at least partially as a function of a dimension of the barrier structure A1114. Started alternatively, the barrier structure A1114 defining, at least in part, a flexible membrane provides one or more of the localized fluid volumes to alter internal volume as a function of at least a change in dimension of the barrier structure, in addition to change in stroke of the piston A1011. The barrier structure A1114 defining, at least in part, the flexible membrane provides varying the internal volume of the chamber at the piston body A1020 at least partially unconstrained by rigidity of the barrier structure A1114, such as to improve sealing. Additionally, or alternatively, the flexible membrane of the barrier structure A1114 beneficially improves the pressure versus volume cycle of the engine. In various embodiments, the flexible structure includes a rolling diaphragm seal or sock seal.
In various embodiments, the chambers A221, A222 defined within the piston body A1020 are substantially fluidly isolated from one another. In one embodiment, the first chamber A221 may be fluidly isolated from the second chamber A222 via a seal assembly A1018 positioned at an interface A1015 between the barrier structure A1114 and the piston assembly A1010. In one embodiment, the seal assembly A1018 and interface A1015 are defined between the piston A1011 and the barrier structure A1114. In another embodiment, the seal assembly A1018 and interface A1015 are defined between the connection member A1030 and the barrier structure A1114. However, it should be appreciated that the seal assembly A1018 may still allow minimal levels of leakage to occur between the first and second chambers A221, A222 but may still render the respective chambers A221, A222 as substantially fluidly isolated from one another.
Referring now to
In one embodiment, the piston A1011 may include a porous or cellular structure within the third chamber A223 such as to provide structural support while further reducing a thermal conduction path at which thermal energy may exchange between the chambers A221, A222 on each side of the piston A1011. The piston A1011 may further include a first material surrounding the third chamber A223 and a second material within the third chamber A223 different from the first material. The second material may define a thermally insulating material, such as a ceramic material.
In various embodiments, the seal assembly A1018 further includes a bearing assembly A1028 allowing load-bearing movement of the piston A1011 within the piston body A1020. The bearing assembly A1028 may define a fluid bearing, a rolling bearing element, a friction bearing, or another suitable type of bearing positioned at the interface A1015 between the barrier structure A1114 of the piston body A1020 and the piston A1011. In one embodiment, the bearing assembly A1028 may be integral to the seal assembly A1018 and the piston A1011 such as to provide fluid sealing between the first and second chambers A221, A222 and to further accept torsional loads, gravitational forces, or other loads not along a lateral direction L (e.g., loads oblique or perpendicular to the lateral direction L) along which the piston assembly A1010 may translate. The bearing assembly A1028 may beneficially provide sealing via the seal assembly A1018 and further configured to counteract vibrations, gravity, torque, or other non-lateral loads in contrast to non-load bearing piston seals that may be provided in internal combustion engines.
Referring still to
During operation of the apparatus A100, a portion of fluid from the first chamber A221 or the second chamber A222 may enter the third chamber A223 via the respective first chamber opening A1012 or second chamber opening A1014, such as to provide pressure to operate the bearing assembly A1028. As one chamber A221, A222 expands or contracts, the other chamber (i.e., the other of chamber A221 or A222) may provide a portion of engine working fluid via the respective opening A1012, A1014 based on the change in pressure (e.g., via the stroke cycle of the piston assembly A1010) at the fluid chambers A221, A222. As such, in various embodiments, the interconnected volume A300 of the first chamber A221 and the second chamber A222 such as described herein may further include the third chamber A223. In still various embodiments, the third chamber A223 is in alternating fluid communication with the first chamber A221 and the second chamber A222 based at least on a stroke of the piston assembly A1010, such as described herein.
In still various embodiments, the apparatus A100 may position the bearing assembly A1028 generally along the lateral direction L at the piston assembly A1010. In various embodiments, the bearing assembly A1028 may be positioned at the connection member A1030 such as to counteract vibrations or loads generally oblique, torsional, or perpendicular to the lateral direction L. In one embodiment, the bearing assembly A1028 is positioned at the connection member A1030 at the piston body A1020.
In one embodiment, a fluid opening A1013 is positioned at the bearing assembly A1028 of the piston A1011. More particularly, the fluid opening A1013 is positioned at the piston A1011 next to the interface A1015 of the barrier structure A1114 interface A1015 and the piston A1011. The fluid opening A1013 provides fluid communication between the third chamber A223 and the bearing assembly A1028. More particularly, the fluid opening A1013 provides fluid communication between the third chamber A223 and an at least partially circumferential groove A1017 at the piston A1011. The groove A1017 provides a pressurized cavity A1019 between the outer wall of the piston A1011 and the barrier structure A1114. More particularly, the groove A1017 is positioned at the interface A1015 of the piston A1011 and the piston body A1020.
During operation of the apparatus A100, the fluid opening A1013 provides fluid to enter and egress from the third chamber A223 and to the cavity A1019 defined by the groove A1017 of the piston A1011 and the piston body A1020. The fluid opening A1013 and the cavity A1019 allow a film of fluid (e.g., engine working fluid, such as helium, hydrogen, air, etc.) to form between the piston A1011 and the piston body A1020. The piston A1011 may at least partially ride on the film of fluid within the cavity A1019, such as to keep the piston A1011 centered within the piston body A1020 or form a protective layer between the piston A1011 and the piston body A1020. The fluid within the cavity A1019 may further provide the bearing assembly A1028 to receive shear forces, or forces generally oblique or perpendicular to the direction of movement of the piston A1011 (e.g., oblique or perpendicular to the lateral direction L).
In another embodiment, a volume of the third chamber A223 is based at least on being large enough to store a portion of the engine working fluid corresponding to the stroke of the piston assembly A1010. In various embodiments, the volume of the third chamber A223 is sufficient to hold working fluid corresponding to the piston assembly A1010 going from full compression to full expansion relative to one volume (e.g., from full compression of the second chamber A222 to full expansion of the same second chamber A222, or from full expansion of the first chamber A221 to full compression of the same first chamber A221, etc.). As such, a sufficient volume or mass of working fluid is at the third chamber A223 and bearing assembly A1028 such as to provide support between the piston A1011 and the piston body A1020. In still another embodiment, the volume of the third chamber A223 is sufficient to hold working fluid corresponding to the piston assembly A1010 going from full compression to full expansion and back to full compression relative to one volume.
It should be appreciated that in still other embodiments the third chamber A223 of the piston A1011 may define a flexible or deformable membrane, similar to as shown and described in regard to the flexible membrane of the barrier structure A1114. In various embodiments, the piston A1011 defining a flexible membrane at the third chamber A223 is deformable such as to provide a substantially constant pressure within the third chamber A223 relative to stroke of the piston assembly A1010. For example, as working fluid exits the third chamber A223, the flexible membrane provides an adjustable volume of the third chamber A223 such as to maintain a substantially constant pressure within the third chamber A223 as working fluid enters and exits the piston A1011.
Referring now to
In various embodiments, the folded cross-section member A1060 provides at least two-times (2×) a flow path distance at the third chamber A223 relative to the length of the piston A1011 along the longitudinal direction L. In a particular embodiment, the folded cross-section member A1060 provides at least four-times (4×) a flow path distance at the third chamber A223 relative to the length of the piston A1011 along the longitudinal direction L. In still another embodiment, the folder cross-section member A1060 may provide ten-times (10×) or less a flow path distance at the third chamber A223 relative to the length of the piston A1011 along the longitudinal direction L.
In certain embodiments, the piston A1011 includes a first monolithic piece A1001 providing an outer shell or heat-shield of the piston A1011. The piston A1011 may further include a second monolithic piece A1002 providing an inner core at which the folded cross-section member A1060 is formed. The first monolithic piece A1011 may generally surround the second monolithic piece A1002. The first monolithic piece A1011 may generally surround the second monolithic piece A1002 such as to separate the second monolithic piece A1002 from the hot chamber A221. In particular embodiments, the first monolithic piece A1001 may define a different material than the second monolithic piece A1002. For instance, the first monolithic piece A1001 may define a material based on desired heat transfer properties relative to the working fluid, temperatures at the hot chamber A221, and/or temperatures at the cold chamber A222. In another instance, the second monolithic piece A1002 may define a material based on desired heat transfer properties of the folded cross-section member A1060, such as to reduce heat flux as described herein.
Referring still to
It should be appreciated that although a first monolithic piece and a second monolithic piece are described herein, one or more additional pieces may be formed, such as to provide heat shielding and/or reduction in heat flux as described herein. Referring now to
Fluid Conduit Heat Exchanger
Referring now to
In another embodiment, the heat exchanger A190 may further include or define a heat pipe in thermal communication with the engine working fluid within the walled conduit A1050. The heat exchanger A190 including a heat pipe may include a cavity between the walled conduit A1050 and an outer wall of the heat exchanger A190. The cavity may include an evaporator portion and a condenser portion. A capillary tube structure (e.g., a wick structure, a screen, channels, grooves, corrugated screen, arteries, tubes, etc.) may further be defined between the walled conduit A1050 and the surrounding outer wall of the heat exchanger A190.
A heat pipe working fluid may be disposed within the heat exchanger A190 defining a heat pipe such as to receive and transfer thermal energy between the engine working fluid within the walled conduit A1050 and the heat pipe working fluid within the heat exchanger A190. In various embodiments, the heat pipe working fluid is any suitable fluid for storing thermal energy within a heat pipe. In one embodiment, the heat pipe working fluid is a phase change fluid or two-phase fluid, such as, but not limited to, helium, nitrogen, ammonia, trichlorofluoromethane, dichlorofluoromethane, pentane, trichlorotrifluoroethane, acetone, methanol, perfluoromethylcyclohexane, ethanol, heptane, water, toluene, perfluoromethyldecalin, a diphenyl ether, mercury, cesium, potassium, sodium, lithium, silver, or combinations thereof. However, it should be appreciated that the heat pipe working fluid may be any suitable two-phase fluid. The suitability of the heat pipe fluid may be based on a desired range of temperature received at the heat pipe working fluid. The suitability of the heat pipe working fluid may additionally, or alternatively, be based on the material of one or more of the walled conduit A1050 or the heat exchanger A190 at which the heat pipe working fluid is contained.
Referring to
Piston Assembly Spring Assembly Arrangement
Referring now to
The springing member A1042 is positioned in serial arrangement with the connection member A1030 and the pistons A1011. In one embodiment, such as depicted in regard to
Referring to
In various embodiments, the springing member A1042 is positioned within the second chamber A222 at one or more of the piston bodies A1020. As such, the springing member A1042 may be defined in substantially parallel arrangement with the second chamber A222 defining a spring.
Referring now to
In one embodiment, each connection member A1030 of each piston assembly A1010 includes a dynamic member of the load device A180 defining an electric machine. The piston assembly A1010 including the dynamic member is in magnetic communication with the load device A180. In various embodiments, the load device A180 further includes a stator assembly A182 operably coupled with each connection member A1030 defining the dynamic member of the load device A180 (e.g., electrical coupling and magnetic communication between the stator assembly A182 and the connection member A1030 including the dynamic member). The load device A180 may include one or more of an inductor, permanent magnet, exciter, pump, etc. proximate to the connection member A1030 of the piston assembly A1010 to generate output power via lateral movement of the piston assembly A1010. In still various embodiments, the load device A180 is includes a battery or capacitor A184 such as to hold or discharge electric current.
Referring still to
Referring to
Referring still to
It should further be appreciated that although various embodiments of the load device A180 provided herein may be configured to alter operation of the plurality of piston assemblies A1010, various embodiments of the apparatus A100 are configured to provide balanced pressure and balanced phase relationship of the plurality of piston assemblies A1010 during operation of the apparatus A100 without the use of the load device A180, or necessitation of the load device A180. As such, it should be appreciated that various embodiments of the apparatus A100 provide operation of the piston assemblies A1010 at substantially the same magnitude as one another without active or passive control from the load device A180.
During operation of the apparatus A100 shown and described in regard to
As the chambers and walled conduits within the interconnected volume are pneumatically disconnected from the chambers and walled conduits outside of the interconnected volume, pressure changes and forces at the interconnected volume, or outside of the interconnected volume, do not propagate to the other chambers and walled conduits (i.e., pressure waves do not propagate from the interconnected volume outside of the interconnected volume, or from outside of the interconnected volume to within the interconnected volume, or from one interconnected volume to another interconnected volume). Additionally, or alternatively, each piston assembly A1010 translates at a substantially identical frequency relative to one another. In various embodiments, each piston assembly A1010 translates in balanced phase relationship relative to one another. In various embodiments, the piston assemblies translate in balanced phase relationship of 90 degrees, or 180 degrees, or 270 degrees relative to one another. In still various embodiments, the balanced phase relationship of the pistons is during operation of the engine when a temperature differential is applied at the first chamber A221 and the second chamber A222. In still yet various embodiments, the balanced phase relationship of the pistons may commence with articulation of at least one first piston assembly A1110 of the apparatus A100.
In various embodiments, the apparatus A100 defines a passively balanced multi-piston assembly apparatus A100 in which each piston assembly A1010 has dynamic motion of its respective connection member A1030. In one embodiment, the piston assembly A1010 has harmonic or oscillation motion respective of its connection member A1030. In another embodiment, the plurality of piston assemblies A1010 each translates at a substantially identical frequency relative to one another.
In still various embodiments, each of the interconnected volumes defines substantially equal internal volumes relative to one another. It should be appreciated that as the apparatus A100 includes the piston assemblies A1010 operating in dynamic motion, though the frequencies are substantially identical and each piston assembly A1010 is out of phase from one another, the internal volumes defining each interconnected volume (i.e., the internal volume at the chambers A221, A222 and the walled conduit A1050 connecting the chambers A221, A222, and any volumes therebetween), are substantially equal as the piston assembly A1010 operates. It should be appreciated that the apparatus A100 provides operation of the piston assemblies A1010 at substantially the same amplitude as one another.
Toroidal Engine Arrangement
Referring now to
Referring still to
The chambers A221, A222 of each piston body A1020 are connected to respective chambers A221, A222 of another piston body A1020 via the plurality of walled conduits A1050 such as described in regard to
Linked Piston Assembly Arrangements
Referring now to
Referring to
Referring to
Referring to
Various embodiments of the apparatus A100 provided herein may include elements or features described or depicted in regard to one embodiment and applied to another embodiment to yield yet other embodiments. For example, embodiments of the fluid coupling of certain chambers A221, A222 to one another via the walled conduit A1050 may be applied to other embodiments of the piston assembly A1010 or apparatus A100 generally. As another example, the load device A180 depicted at the inner end A104 may in other embodiments be positioned at the outer end A103 or out of alignment from the piston assembly A1010. In still another embodiment, the hot side heat exchanger A160 may be positioned at either the outer end A103 or the inner end A104 and the first chamber A221 may be positioned correspondingly at the outer end A103 or the inner end A104. Alternatively, the cold side heat exchanger A170 may be positioned at either the inner end A104 or the outer end A103 and the second chamber A222 may be positioned correspondingly at the inner end A104 or the outer end A103.
In still various embodiments, a single hot side heat exchanger A160, or heater assembly generally, may be positioned to provide thermal energy to each of the plurality of first chambers A221. Similarly, a single cold side heat exchanger A170, or chiller assembly generally, may be positioned to remove or receive thermal energy from each of the plurality of second chambers A222. It should further be appreciated that certain embodiments may advantageously position the first chamber A221 and/or the second chamber A222 such as to improve overall packaging of the apparatus A100, such as to reduce overall size and dimension relative to power output (i.e., to improve power density). For example, referring to
Referring still to
In still various embodiments of the apparatus A100 and system A10 shown and described herein, a plurality of the connection member A1030 may be operably connected together to multiply power output at the load device C092. In one embodiment, a plurality of the apparatus A100 may be configured to operate in substantially similar phase arrangement as one another. For instance, the plurality of apparatuses A100 may each include a first connection member corresponding to a first piston assembly (e.g., A110 in
Various embodiments of the apparatus A100 shown and described herein may be fabricated via one or more manufacturing methods known in the art, such as, but not limited to, additive manufacturing, binder jetting, or 3D printing processes generally, machining processes, material addition or removal processes, or joining or bonding processes. Manufacturing processes may include, but are not limited to, casting, welding, brazing, soldering, or bonding processes. Materials may include those suitable for piston assemblies and pressure vessels configured to receive thermal differentials and operate for desired cycles and power outputs, including rigid and flexible wall members, enclosures, and conduits. Although certain exemplary embodiments may preferably be produced via one or more additive manufacturing processes, it should be appreciated that other manufacturing processes, or combinations thereof, may be utilized. Still further, although certain elements or structures may be produced as substantially monolithic structures, certain elements may be attached or otherwise coupled via welding, brazing, or mechanical fasteners, such as, but not limited to, clamps, nuts, bolts, screws, tie rods, washers, etc.
As used herein, the terms “additively manufactured” or “additive manufacturing techniques or processes” refer generally to manufacturing processes wherein successive layers of material(s) are provided on each other to “build-up,” layer-by-layer, a three-dimensional component. The successive layers generally fuse together to form a monolithic component which may have a variety of integral sub-components.
Although additive manufacturing technology is described herein as providing fabrication of complex objects by building objects point-by-point, layer-by-layer, typically in a vertical direction, other methods of fabrication are possible and are within the scope of the present subject matter. For example, although the discussion herein refers to the addition of material to form successive layers, one skilled in the art will appreciate that the methods and structures disclosed herein may be practiced with any additive manufacturing technique or manufacturing technology. For example, embodiments of the present disclosure may use layer-additive processes, layer-subtractive processes, or hybrid processes. As another example, embodiments of the present disclosure may include selectively depositing a binder material to chemically bind portions of the layers of powder together to form a green body article. After curing, the green body article may be pre-sintered to form a brown body article having substantially all of the binder removed, and fully sintered to form a consolidated article.
Suitable additive manufacturing techniques in accordance with the present disclosure include, for example, Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjets and laserjets, Stereolithography (SLA), Direct Laser Sintering (DLS), Direct Selective Laser Sintering (DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM), Laser Engineered Net Shaping (LENS), Laser Net Shape Manufacturing (LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP), Direct Laser Melting (DLM), Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM), Direct Metal Laser Melting (DMLM), Binder Jetting (BJ), and other known processes.
The additive manufacturing processes described herein may be used for forming components using any suitable material. For example, the material may be plastic, metal, concrete, ceramic, polymer, epoxy, photopolymer resin, or any other suitable material that may be in solid, liquid, powder, sheet material, wire, or any other suitable form or combinations thereof. More specifically, according to exemplary embodiments of the present subject matter, the additively manufactured components described herein may be formed in part, in whole, or in some combination of materials including but not limited to pure metals, nickel alloys, chrome alloys, titanium, titanium alloys, magnesium, magnesium alloys, aluminum, aluminum alloys, and nickel or cobalt based superalloys (e.g., those available under the name Inconel® available from Special Metals Corporation). These materials are examples of materials suitable for use in the additive manufacturing processes described herein, and may be generally referred to as “additive materials.”
In addition, one skilled in the art will appreciate that a variety of materials and methods for bonding those materials may be used and are contemplated as within the scope of the present disclosure. As used herein, references to “fusing” or “binding” may refer to any suitable process for creating a bonded layer of any of the above materials. For example, if an object is made from polymer, fusing may refer to creating a thermoset bond between polymer materials. If the object is epoxy, the bond may be formed by a crosslinking process. If the material is ceramic, the bond may be formed by a sintering process. If the material is powdered metal, the bond may be formed by a melting or sintering process, or additionally with a binder process. One skilled in the art will appreciate that other methods of fusing materials to make a component by additive manufacturing are possible, and the presently disclosed subject matter may be practiced with those methods.
In addition, the additive manufacturing process disclosed herein allows a single component to be formed from multiple materials. Thus, the components described herein may be formed from any suitable mixtures of the above materials. For example, a component may include multiple layers, segments, or parts that are formed using different materials, processes, and/or on different additive manufacturing machines. In this manner, components may be constructed which have different materials and material properties for meeting the demands of any particular application. In addition, although the components described herein are constructed entirely by additive manufacturing processes, it should be appreciated that in alternate embodiments, all or a portion of these components may be formed via casting, machining, and/or any other suitable manufacturing process. Indeed, any suitable combination of materials and manufacturing methods may be used to form these components.
An exemplary additive manufacturing process will now be described. Additive manufacturing processes fabricate components using three-dimensional (3D) information, for example a three-dimensional computer model, of the component. Accordingly, a three-dimensional design model of the component may be defined prior to manufacturing. In this regard, a model or prototype of the component may be scanned to determine the three-dimensional information of the component. As another example, a model of the component may be constructed using a suitable computer aided design (CAD) program to define the three-dimensional design model of the component.
The design model may include 3D numeric coordinates of the entire configuration of the component including both external and internal surfaces of the component. For example, the design model may define the body, the surface, and/or internal passageways such as openings, support structures, etc. In one exemplary embodiment, the three-dimensional design model is converted into a plurality of slices or segments, e.g., along a central (e.g., vertical) axis of the component or any other suitable axis. Each slice may define a thin cross section of the component for a predetermined height of the slice. The plurality of successive cross-sectional slices together form the 3D component. The component is then “built-up” slice-by-slice, or layer-by-layer, until finished.
In this manner, the components described herein may be fabricated using the additive process, or more specifically each layer is successively formed, e.g., by fusing or polymerizing a plastic using laser energy or heat or by sintering or melting metal powder. For example, a particular type of additive manufacturing process may use an energy beam, for example, an electron beam or electromagnetic radiation such as a laser beam, to sinter or melt a powder material. Any suitable laser and laser parameters may be used, including considerations with respect to power, laser beam spot size, and scanning velocity. The build material may be formed by any suitable powder or material selected for enhanced strength, durability, and useful life, particularly at high temperatures.
Each successive layer may be, for example, between about 10 μm and 200 μm, although the thickness may be selected based on any number of parameters and may be any suitable size according to alternative embodiments. Therefore, utilizing the additive formation methods described above, the components described herein may have cross sections as thin as one thickness of an associated powder layer, e.g., 10 μm, utilized during the additive formation process.
In addition, utilizing an additive process, the surface finish and features of the components may vary as need depending on the application. For example, the surface finish may be adjusted (e.g., made smoother or rougher) by selecting appropriate laser scan parameters (e.g., laser power, scan speed, laser focal spot size, etc.) during the additive process, especially in the periphery of a cross-sectional layer which corresponds to the part surface. For example, a rougher finish may be achieved by increasing laser scan speed or decreasing the size of the melt pool formed, and a smoother finish may be achieved by decreasing laser scan speed or increasing the size of the melt pool formed. The scanning pattern and/or laser power can also be changed to change the surface finish in a selected area.
After fabrication of the component is complete, various post-processing procedures may be applied to the component. For example, post processing procedures may include removal of excess powder by, for example, blowing or vacuuming. Other post processing procedures may include a stress relief process. Additionally, thermal, mechanical, and/or chemical post processing procedures can be used to finish the part to achieve a desired strength, surface finish, a decreased porosity decreasing and/or an increased density (e.g., via hot isostatic pressing), and other component properties or features.
It should be appreciated that one skilled in the art may add or modify features shown and described herein to facilitate manufacture of the system A10 provided herein without undue experimentation. For example, build features, such as trusses, grids, build surfaces, or other supporting features, or material or fluid ingress or egress ports, may be added or modified from the present geometries to facilitate manufacture of embodiments of the system A10 based at least on a desired manufacturing process or a desired particular additive manufacturing process.
Notably, in exemplary embodiments, several features of the components described herein were previously not possible due to manufacturing restraints. However, the present inventors have advantageously utilized current advances in additive manufacturing techniques to develop exemplary embodiments of such components generally in accordance with the present disclosure. While certain embodiments of the present disclosure may not be limited to the use of additive manufacturing to form these components generally, additive manufacturing does provide a variety of manufacturing advantages, including ease of manufacturing, reduced cost, greater accuracy, etc.
In this regard, utilizing additive manufacturing methods, even multi-part components may be formed as a single piece of continuous metal, and may thus include fewer sub-components and/or joints compared to prior designs. The integral formation of these multi-part components through additive manufacturing may advantageously improve the overall assembly process, reduce potential leakage, reduce thermodynamic losses, improve thermal energy transfer, or provide higher power densities. For example, the integral formation reduces the number of separate parts that must be assembled, thus reducing associated time, overall assembly costs, reduces potential leakage pathways, or reduces potential thermodynamic losses. Additionally, existing issues with, for example, leakage, may advantageously be reduced. Still further, joint quality between separate parts may be addressed or obviated by the processes described herein, such as to desirably reduce leakage, assembly, and improve overall performance.
Also, the additive manufacturing methods described above provide much more complex and intricate shapes and contours of the components described herein to be formed with a very high level of precision. For example, such components may include thin additively manufactured layers, cross sectional features, and component contours. As another example, additive manufacturing may provide heat exchanger surface areas, volumes, passages, conduits, or other features that may desirably improve heat exchanger efficiency or performance, or overall engine or system performance. In addition, the additive manufacturing process provides the manufacture of a single component having different materials such that different portions of the component may exhibit different performance characteristics. The successive, additive steps of the manufacturing process provide the construction of these novel features. As a result, the components described herein may exhibit improved functionality and reliability.
It should be appreciated that performances, power outputs, efficiencies, or temperature differentials at the system A10, the engine A100, or both, provided herein may be based on a “Sea Level Static” or “Standard Day” input air condition such as defined by the United States National Aeronautics and Space Administration, unless otherwise specified. For example, unless otherwise specified, conditions provided to the heater body, the chiller assembly, or both, or any subsystems, components, etc. therein, or any other portions of the system A10 receiving an input fluid, such as air, are based on Standard Day conditions.
The heat transfer relationships described herein may include thermal communication by conduction and/or convection. A heat transfer relationship may include a thermally conductive relationship that provides heat transfer through conduction (e.g., heat diffusion) between solid bodies and/or between a solid body and a fluid. Additionally, or in the alternative, a heat transfer relationship may include a thermally convective relationship that provides heat transfer through convection (e.g., heat transfer by bulk fluid flow) between a fluid and a solid body. It will be appreciated that convection generally includes a combination of a conduction (e.g., heat diffusion) and advection (e.g., heat transfer by bulk fluid flow). As used herein, reference to a thermally conductive relationship may include conduction and/or convection; whereas reference to a thermally convective relationship includes at least some convection.
A thermally conductive relationship may include thermal communication by conduction between a first solid body and a second solid body, between a first fluid and a first solid body, between the first solid body and a second fluid, and/or between the second solid body and a second fluid. For example, such conduction may provide heat transfer from a first fluid to a first solid body and/or from the first solid body to a second fluid. Additionally, or in the alternative, such conduction may provide heat transfer from a first fluid to a first solid body and/or through a first solid body (e.g., from one surface to another) and/or from the first solid body to a second solid body and/or through a second solid body (e.g., from one surface to another) and/or from the second solid body to a second fluid.
A thermally convective relationship may include thermal communication by convection (e.g., heat transfer by bulk fluid flow) between a first fluid and a first solid body, between the first solid body and a second fluid, and/or between a second solid body and a second fluid. For example, such convection may provide heat transfer from a first fluid to a first solid body and/or from the first solid body to a second fluid. Additionally, or in the alternative, such convection may provide heat transfer from a second solid body to a second fluid.
It will be appreciated that the terms “clockwise” and “counter-clockwise” are terms of convenience and are not to be limiting. Generally, the terms “clock-wise” and “counter-clockwise” have their ordinary meaning, and unless otherwise indicated refer to a direction with reference to a top-down or upright view. Clockwise and counter-clockwise elements may be interchanged without departing from the scope of the present disclosure.
Where temperatures, pressures, loads, phases, etc. are said to be substantially similar or uniform, it should be appreciated that it is understood that variations, leakages, or other minor differences in inputs or outputs may exist such that the differences may be considered negligible by one skilled in the art. Additionally, or alternatively, where temperatures or pressures are said to be uniform, i.e., a substantially uniform unit (e.g., a substantially uniform temperature at the plurality of chambers A221), it should be appreciated that in one embodiment, the substantially uniform unit is relative to an average operating condition, such as a phase of operation of the engine, or thermal energy flow from one fluid to another fluid, or from one surface to a fluid, or from one surface to another surface, or from one fluid to another surface, etc. For example, where a substantially uniform temperature is provided or removed to/from the plurality of chambers A221, A222, the temperature is relative to an average temperature over a phase of operation of the engine. As another example, where a substantially uniform thermal energy unit is provided or removed to/from the plurality of chambers A221, A222, the uniform thermal energy unit is relative to an average thermal energy supply from one fluid to another fluid relative to the structure, or plurality of structures, through which thermal energy transferred.
Various interfaces, such as mating surfaces, interfaces, points, flanges, etc. at which one or more monolithic bodies, or portions thereof, attach, couple, connect, or otherwise mate, may define or include seal interfaces, such as, but not limited to, labyrinth seals, grooves into which a seal is placed, crush seals, gaskets, vulcanizing silicone, etc., or other appropriate seal or sealing substance. Additionally, or alternatively, one or more of such interfaces may be coupled together via mechanical fasteners, such as, but not limited to, nuts, bolts, screws, tie rods, clamps, etc. In still additional or alternative embodiments, one or more of such interfaces may be coupled together via a joining or bonding processes, such as, but not limited to, welding, soldering, brazing, etc., or other appropriate joining process.
It should be appreciated that ratios, ranges, minimums, maximums, or limits generally, or combinations thereof, may provide structure with benefits not previously known in the art. As such, values below certain minimums described herein, or values above certain maximums described herein, may alter the function and/or structure of one or more components, features, or elements described herein. For example, ratios of volumes, surface area to volume, power output to volume, etc. below the ranges described herein may be insufficient for desired thermal energy transfer, such as to undesirably limit power output, efficiency, or Beale number. As another example, limits greater than those described herein may undesirably increase the size, dimensions, weight, or overall packaging of the system or engine, such as to undesirably limit the applications, apparatuses, vehicles, usability, utility, etc. in which the system or engine may be applied or operated. Still further, or alternatively, undesired increases in overall packaging may undesirably decrease efficiency of an overall system, application, apparatus, vehicle, etc. into which the engine may be installed, utilized, or otherwise operated. For example, although an engine may be constructed defining a similar or greater efficiency as described herein, such an engine may be of undesirable size, dimension, weight, or overall packaging such as to reduce an efficiency of the system into which the engine is installed. As such, obviation or transgression of one or more limits described herein, such as one or limits relative to features such as, but not limited to, heater conduits, chiller conduits A54, chamber volumes, walled conduit volumes, or operational temperatures, or combinations thereof, may undesirably alter such structures such as to change the function of the system or engine.
Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to describe the presently disclosed subject matter, including the best mode, and also to provide any person skilled in the art to practice the subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the presently disclosed subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. The scope of the invention(s) described herein is defined by one or more of the claims, including combinations of two or more claims or clauses (as set forth below) and may include other examples that occur to those skilled in the art. For example, aspects of the invention(s) are provided by the subject matter of the following clauses, which are intended to cover all suitable combinations unless dictated otherwise based on logic or the context of the clauses and/or associated figures and description:
The present application is a national stage application under 35 U.S.C. § 371 of PCT application serial number PCT/US2020/033710, filed May 20, 2020, which claims the benefit of the earliest available effective filing date of U.S. Provisional Patent Application No. 62/850,701, U.S. Provisional Patent Application No. 62/850,678, U.S. Provisional Patent Application No. 62/850,599, U.S. Provisional Patent Application No. 62/850,623, and U.S. Provisional Patent Application No. 62/850,692, each having a filing date of May 21, 2019, and each of which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/033710 | 5/20/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/236877 | 11/26/2020 | WO | A |
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| Chinese Office Action Corresponding to Application No. 202080051965 on Nov. 22, 2023. |
| Number | Date | Country | |
|---|---|---|---|
| 20220195959 A1 | Jun 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62850599 | May 2019 | US | |
| 62850623 | May 2019 | US | |
| 62850678 | May 2019 | US | |
| 62850692 | May 2019 | US | |
| 62850701 | May 2019 | US |
