Patent Application
20210332718
The subject matter disclosed herein relates to heat transfer systems and, more specifically, to heat transfer systems in turbomachinery.
Turbomachinery, such as gas turbine systems, may provide for the generation of power. For example, many gas turbine systems typically include a compressor section for compressing a working fluid, such as air, a combustor for combusting the compressed working fluid with fuel, and a turbine section for turning the combusted fluid into a rotative power. The compressed air is injected into the combustor, where it is combined with fuel to create combustion gases that expand as the combustion gases enter the turbine section. The expanded fluid is forced through the turbine section. The turbine section may then convert the expanded fluid into rotative power, for example, by a series of blade stages. The rotative power may then be used to drive a load, which may include an electrical generator for producing electrical power and which may be electrically coupled to a power distribution grid.
Turbomachinery may generate heat during operations. It may be useful to improve heat transfer of turbomachinery.
Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief summary of possible forms of the subject matter. Indeed, the present system may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a heat management system includes a thermal delivery system configured to providing heating, cooling, or a combination thereof, to a turbomachinery. The thermal delivery system includes a first heat transfer conduit and a second heat transfer conduit disposed on the turbomachinery adjacent to the first heat transfer conduit. The heat management system additionally includes a controller operatively coupled to the thermal delivery system and configured to control the heating, the cooling, or the combination thereof, of the turbomachinery via the thermal delivery system.
In a second embodiment, a method includes providing heating, cooling, or a combination thereof, to a turbomachinery via a first heat transfer conduit and a second heat transfer conduit included in a thermal delivery system, wherein the second heat transfer conduit is disposed on the turbomachinery adjacent to the first heat transfer conduit. The method further includes controlling the heating, the cooling, or the combination thereof, of the turbomachinery, via a controller operatively coupled to the thermal delivery system, to minimize or to eliminate positional changes, structural changes, or a combination thereof, in one or more components of the turbomachinery due to thermal energy.
In a third embodiment, a non-transitory computer readable medium includes executable instructions which, when executed by a processor, cause the processor to provide heating, cooling, or a combination thereof, to a turbomachinery via a first heat transfer conduit and a second heat transfer conduit included in a thermal delivery system, wherein the second heat transfer conduit is disposed on the turbomachinery adjacent to the first heat transfer conduit. The instructions further cause the processor to control the heating, the cooling, or the combination thereof, of the turbomachinery, via a controller operatively coupled to the thermal delivery system, to minimize or to eliminate positional changes, structural changes, or a combination thereof, in one or more components of the turbomachinery due to thermal energy.
These and other features, aspects, and advantages of the present subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present subject matter will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present subject matter, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
The disclosed embodiments include a heat transfer or heat management system that may be used by a variety of turbomachinery. For example, a gas turbine system may include a heat management system that may provide heat and/or cooling to certain components, e.g., casings or shells of compressors, combustors, turbines, and so on, during certain operations, such as shutdown operations. For example, during shutdown operations, a lower shell of the gas turbine system may cool faster than an upper shell, which may lead to expansion/contractions of certain components, and consequent distortions of casing(s). The heat management system may provide heating and/or cooling to compensate for thermal differences, thus improving operations of the turbomachinery.
In one embodiment, the heat management system includes heat transfer conduits (e.g., wires, pipes) that may be routed symmetrically for improved heat transfer reliability. The heat transfer conduits may include certain gap ranges between the heat transfer conduits themselves as well as certain gap ranges relative to certain components of turbomachinery (e.g., casing) to improve the transfer of heat. The heat management system may further include reflective foils and an insulation cover. The reflective foils or other wrappers may also be used to moderately isolate a short length of heat transfer conduit with attached sensors (e.g., thermocouples) in addition to controlling a spacing between the heat transfer conduits and insulation. Single fastener techniques may be used to fasten the heat management system to the turbomachinery.
In some embodiments, the heat management system may include a controller communicatively coupled to one or more sensors, such as thermocouples, disposed in various portions of the turbomachinery (e.g., a gas turbine system). The controller may be operatively coupled to one or more heating and/or cooling systems disposed in the turbomachinery. The controller may use zone control to control heat and/or cooling of one or more zones in the turbomachinery.
In one embodiment, the zone control may include double redundant application of heat/cooling and/or double redundant sensing. For example, a first zone adjacent to a second zone may provide for heating and/or cooling redundancy to the second zone should the heating/cooling equipment in the second zone develop maintenance issues. Likewise, a first sensor disposed in a first zone, area, or subsystem of the turbomachinery may provide redundancy for a second sensor disposed in a second zone, area, or subsystem. For example, the first sensor may be disposed in a first subsystem and the second sensor may be disposed in a second subsystem, but by using the techniques described herein, the first sensor may provide for data useful in determining conditions of the second subsystem should the second sensor become inoperative. By providing heating systems with double redundant application of heat/cooling and/or double redundant sensing, the techniques described herein may increase operational life and efficiency of turbomachinery.
The mechanical systems described herein may enable a more even heating of certain components, e.g. casings, as well as provide for redundancy during heating operations. For example, thermal conduits may be provided, adjacent to other conduits. In one example, two conduits may be parallel but offset some small amount (e.g., between 0.25 inches and 5 inches) from each other. The conduits may also be adjacent to and/or abut against the casing. For example, the conduits may be 0 inches to 0.2 inches from the casing. A reflective foil may be used, to aid in thermal transfer, for example, by reflecting radiation and thus reducing heat transfer that may occur through radiation. In certain embodiments, a “wrap” may be used, to partially or fully enclose a conduit and/or a temperature sensor to improve temperature delivery and/or measurements, as further described below.
Turning now to
The controller 14 may be operatively coupled to the thermal delivery systems 18 to provide for heating and/or cooling of certain zones within the turbomachinery 10, such as locations on the top shell 11 and the bottom shell 13. The thermal delivery systems 18 may include heating blankets (e.g., electrically heated blankets), heat exchangers (e.g., fluid-based heat exchangers), refrigeration systems, radiative heat systems, and so on, suitable for generating heat and/or removing heat.
In use, the turbomachinery 10 may experience heat gradients. For example, when the turbomachinery 10 is a gas turbine system, the bottom shell 13 may cool faster than the top shell 11 during shutdown. That is, as heat rises due to buoyancy, the bottom shell 13 may be at a lower temperature compared to the top shell 11, which may result in unwanted effects. For example, the bottom shell 13 may contract while the top shell 11 may expand, which may result in casing bending. The controller 14 may receive a plurality of signals from the sensors 16 representative of the temperature at each sensor 16 and apply certain heating and/or cooling via the thermal delivery systems 18, as described in more detail below, to minimize or eliminate certain heat-related effects, such as the casing bending. Accordingly, the controller 14 may include one or more processors 19 and memory 21. The memory 21 may store computer code or instructions executable by the processor(s) 19.
For example, when the turbomachinery 10 is a gas turbine system, some of the sensors 16 may be used to provide for temperature and/or other measurements during operations of the turbomachinery 10. For example, the sensors 16 may include wheel space thermocouples, exhaust gas temperature thermocouples, compressor discharge temperature thermocouples, combustion temperature thermocouples, and so on. Additionally or alternatively, sensors that measure clearance (e.g., rotor clearance, clearance between two or more components) may be used.
The thermal delivery systems 18 may also be disposed on various locations of the turbomachinery 10. In one embodiment, the thermal delivery systems 18 may be disposed on the bottom shell 13 and used to heat the bottom shell 13 to provide for more equal heating of the top shell 11 and the bottom shell 13. That is, by heating the bottom shell 13 at one or more zones, the one or more zones of the bottom shell 13 may be kept at similar temperatures to areas of the top shell 11 that would have experienced more heat without the techniques described herein. By maintaining more optimized top-to-bottom temperature differences, the turbomachinery 10 may, for example, go through a shutdown cycle with minimal or no clearance eccentricity.
In other embodiments, thermal delivery systems 18 may be disposed on the top shell 11 as well as the bottom shell 13. In these embodiments, the thermal delivery systems 18 on the top shell 11 may provide for cooling, such as via heat exchangers (e.g., system with conduits that move a cooling fluid into a zone and leave with a heated fluid, thus extracting heat). By combining heating on the bottom shell 13 with cooling on the top shell 11, certain operations, such as turbine shutdown operations, may be improved while increasing the lifecycle of equipment.
In yet other embodiments, the thermal delivery systems 18 may provide both heating and cooling, for example, by circulating a heated fluid and a cooling fluid based on an amount of heat to be added or to be extracted. The thermal delivery systems 18 may be disposed on the shells 11, 13, or in any location of the turbomachinery 10 that would benefit from heat and/or cooling during certain operations. Indeed, the thermal delivery systems 18 may be disposed in various subsystems of the turbomachinery 10 and may be operatively coupled to the controller 14. The thermal delivery systems 18 may include electrically heated “blankets”, heat exchangers, heat recuperators, radiative heaters, and so on.
It may be beneficial to describe an embodiment where the turbomachinery is a gas turbine system. Accordingly,
In operation, the compressor 20 is configured to compress a compressible fluid (e.g., gas such as air, oxygen, and/or exhaust gas) and to deliver the compressed fluid to the fuel nozzles 24 and/or combustors 26. Although the compressible fluid may include any suitable gas, the following discussion may generally refer to the compressible fluid as an oxidant (e.g., air) as one non-limiting example. The fuel nozzles 24 are configured to supply fuel (e.g., from one or more fuel supplies) into the one or more combustors 26 (e.g., into combustion chambers), which combust the fuel with the oxidant (e.g., air) to generate hot combustion gases to drive the turbine 22.
The fuel nozzles 24 may be designed as pre-mix fuel nozzles 24 and/or diffusion fuel nozzles 24. Pre-mix fuel nozzles 24 mix the fuel with the oxidant (e.g., air) within the fuel nozzles 24 to create pre-mix type flames. Diffusion fuel nozzles 24 do not premix the fuel with the oxidant and thus create diffusion type flames when the fuel and air are separately introduced into the combustion zone. Regardless of the type of flames, the hot combustion gas flows from the combustors 26 into the turbine 22, thereby driving rotation of one or more stages of turbine blades coupled to a turbine rotor and shaft 30 along an axis 32. Eventually, the hot combustion gas exits the turbine 22 through an exhaust outlet 28 (e.g., exhaust stack, exhaust end).
In the illustrated embodiment, the shaft 30 is coupled to the compressor 20 and a load 36, such that rotation of the shaft 30 also drives rotation of the compressor 20 and the load 36. The compressor 20 may intake the oxidant (e.g., air) through an air intake 34, which may include filters, thermal control systems, or any other preconditioning systems. The load 36 may include an electrical generator, a rotary machine, a propulsion system of a vehicle, or any other suitable device. It is to be noted that the thermal management systems and methods described herein are also applicable to a two-shaft (or more) turbine with a load coupled to a power turbine that may be independent of a compressor and/or gas generator.
During shutdown, heat may be removed from the bottom shell 13 at a faster rate than heat is removed from the top shell 11. Heat from the bottom shell 13 rises toward the top shell 11, as shown by arrows 50 in
It would be beneficial to heat the bottom shells 13 and/or cool the top shells 11 to maintain more equal temperatures. Accordingly, the heat management system 17 (shown in
Zones and subzones may be selected for heating and/or cooling based on, for example, thermal studies that analyze the materials, thicknesses, manufacturing data, and/or geometries of the shells (e.g., shells 11, 13), subsystems (e.g., rotor 30, components of the intake section 34, compressor section 20, fuel nozzles 24, combustor 26, turbine 22, exhaust 28, and so on) to determine or otherwise model heat flows through the gas turbine engine 12. The heat flows may then be used to determine zones and subzones for heating and/or cooling. The heat flows may also be used to determine heating schedules for heating and/or cooling zones and/or subzones. For heating purposes, each heating/cooling unit may include an axial heating “strip” that may use electrical heating. Other heating embodiments may include heat exchangers, heat recuperators, radiative heaters, microwave heating elements, and so on. For cooling purposes, heat exchangers, refrigeration systems, and so on may be used.
In certain embodiments, each subzone (or zone having a single subzone) may be independently controlled by the controller 14. That is, the heating and/or cooling schedule may be provided for each subzone (or zone having a single subzone) that may be different for other subzones. In some embodiments, some subzones (e.g., adjacent subzones) may follow the same heating and/or cooling schedule. The heating and/or cooling schedule may be used to determine how much heating and/or cooling to apply at a given point in time (e.g., time following the start of shutdown).
Zones and/or subzones may also be used to provide redundant operations. For example, should a heating/cooling unit experience operating issues, adjacent heating/cooling units may enter into a redundancy mode where the adjacent heating/cooling units may provide added heating or cooling to compensate for the loss of heating or cooling of the heating/cooling unit experiencing the issue. In some embodiments, redundancy mode heating and/or cooling schedules may be provided, which may have been derived based on thermal analysis of a zone and/or subzone experiencing heating/cooling unit issues (e.g., failure of the heating/cooling unit).
That is, a redundancy mode heating and/or cooling schedule may be derived that increases heating and/or cooling for a given working zone and/or subzone based on issues experienced by adjacent zones and/or subzones. For example, the heating and/or cooling schedule may be used to apply heat and/or cooling via a time-based mode without using sensors. That is, the heating and/or cooling blanket may be turned on (at full power, partial power, or desired power level) for a given time to provide heat and/or cooling and then turned off without sensing temperature. Accordingly, the controller 14 may switch from normal operations to redundant operations, for example, by switching to using redundancy mode heating and/or cooling schedule(s).
In some embodiments, the thermal delivery systems 18 may be added after installation of the turbomachinery 10. For example, the thermal delivery systems 18 may be provided as an after-install kit or as an upgrade kit and installed in situ. For example, the depicted heating blanket embodiment of the thermal delivery system 18 may be placed on exterior walls of the shells 11 and/or 13 and may be secured via fasteners, such as straps, nuts and bolts, welds, adhesives, and so on. Sensors 16 and conduits used to operate heating elements may then be connected to the controller 14. For example, the various conduits that may be used are described in
In use, the controller 14 may receive from the sensor 16 signals that are representative of temperature in a zone of a shell (e.g., shown as embedded in a section of the bottom shell 13). Accordingly, the controller 14 may adjust electric power through the conduit 70 to raise or lower the heat provided by the thermal delivery system 18. While two insulation layers 80 and 82 are shown, one, three, four, or more layers may be used. The sensor 16 senses temperatures being delivered via the heating blanket 76, for example, to protect from overheating of the heating blanket 76 itself, and conveys such signals to the controller 14 via conduits 72, 74. It is to be understood that the heating blanket shown is but one embodiment of the thermal delivery system 18, and other embodiments may include heat exchangers and the like, suitable for adding heat to a zone.
Turning now to
In the depicted embodiment, the heat transfer conduits 152, 154 are disposed alongside each other. That is, heat transfer conduit 152 may follow the same contours (e.g., curvature) as the heat transfer conduit 154, and the heat transfer conduits 152, 154 may be parallel with respect to each other and/or may be offset a certain amount from each other. In one embodiment, the heat transfer conduit 152 may be identical (e.g., have the same size and shape) to the heat transfer conduit 154 but may be placed offset and/or parallel to the heat transfer conduit 154. For example, the heat transfer conduits 152, 154 may be between 0.25 inches and 5 inches from each other. The heat transfer conduits 152, 154 may be placed to follow certain contours (e.g., blanket contours, casing contours) and may thus include curved portions. In certain embodiments, the conduits 152, 154 may cover a specified area in the circumferential direction (e.g., over an arc such as between + or −45°) to cover a zone or a subzone, such that loss of a zone or subzone would not cause lateral bending of the casing or shell.
In the depicted embodiment, the heat transfer conduits are operatively coupled to the controller 14 via a circuitry 156, such as a pulse width modulation (PWM) circuitry 156 and, more specifically, a silicon-controlled rectifier (SCR)-based circuitry. In operations, the PWM circuitry 156 may deliver three-phase power to each of the heat transfer conduits 152, 154, for example, at a voltage between 360-660 volts. Because of lateral symmetry, if heating issues arise in one of the heat transfer conduits 152, 154, the other heat transfer conduit 152, 154 is configured to provide redundancy of operations.
That is, should a heat transfer conduit 152 or 154 fail, the other heat transfer conduit 152 or 154 may still provide enough heat to continue operations (e.g., shutdown operations) of the gas turbine engine 12. For example, if a heat transfer conduit 152 fails, then neighboring heat transfer conduits 154 may adjust heating schedules (as mentioned earlier) to compensate for the loss of the heat transfer conduit 152 and continue operations to prevent rotor rubs. While the depicted embodiment shows two heat transfer conduits 152, 154, three, four, five, six, or more heat transfer conduits may be disposed laterally symmetrical with respect to each other. It is also to be noted that the heat transfer conduits 152, 154 (or more) may be disposed to cover desired areas of the casing 150, such as the zones and/or subzones described in the figures above.
Turning now to
Also depicted is a reflective foil layer 160. The reflective foil layer 160 may reduce heat transfer through radiation by reflecting thermal radiation back toward the casing 150. The reflective foil layer 160 may also control a spacing between an insulation layer 162 and the heat transfer conduit 152. The heat transfer conduit 152 (optionally, 154) of the heat management system may be fastened onto the casing 150 via fasteners 164, such as nuts and bolts, screws, and so on.
In one embodiment, each of the heat transfer conduits 152 may include one wrapped portion 172 disposed in the middle of the heat transfer conduit 152. For example, if a heat transfer conduit 152 has a length of 6 feet, then the wrapped portion 172 may be disposed in the middle, e.g., about three feet from the start of the heat transfer conduit 152. In other embodiments, a plurality of wrapped portions 172 may be disposed along the length of the heat transfer conduit 152. In some embodiments, each of the plurality of wrapped portions 172 may be disposed to divide the heat transfer conduit 152 into approximately equal or equal segments between the wrapped portions 172.
In the depicted embodiment, the wrap 173 may cover all sides of the heat transfer conduit 152 in a single layer and may also enclose the sensor 16. In use, the wrapped portion 172 may improve temperature sensing of the heat transfer conduit 152. For example, if the sensor 16 was not wrapped, the sensor 16 may not be as accurate in sensing the heat transfer conduit 152, as heat applied may be transferred into the casing and thus the sensor 16 may get a lower heat reading. Accordingly, the techniques described herein provide for improved thermal manipulation suitable for enhancing casing life and for minimizing and/or eliminating casing bends or distortions.
The heating elements may be three-phase heating elements having A, B, and C phases. In the depicted embodiment, 1A depicts heating element 1 phase A, 1B depicts heating element 1 phase B, and 1C depicts heating element 1 phase C. Likewise, 2A depicts heating element 2 phase A, 2B depicts heating element 2 phase B, and 2C depicts heating element 2 phase C. In some embodiments, each phase A, B, and C may be controlled independently, while in other embodiments phases A, B, and C may be controlled as one. In the latter embodiments, if a phase A, B, or C is found not to be functioning as desired, then all phases of the heating element may be turned off.
Because the heaters may completely traverse from one side (e.g., side 206) to the other side (e.g., side 208), then lateral heating symmetry is provided. That is, if a heater or heater phase is off, then no one side should heat (or cool) differently from the other. Indeed, rather than heat (or cool) via “patches” covering the area 200, the techniques described herein may heat (or cool) evenly from side to side, thus maintaining lateral symmetry. In embodiments where all three phases are controlled together, it may be beneficial to interweave certain of the phases, as shown in
More specifically,
This written description uses examples to disclose the subject matter, including the best mode, and also to enable 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 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 have 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 language of the claims.
