Patent Application
20110097189
The present disclosure relates to a boundary layer effect gas microturbine for the purpose of producing a torque for mechanical work or to generate electric power.
Reciprocating internal combustion engines have long been used to replace man power with that of the machine. In these engines, a linear motion is imparted to one or more reciprocating pistons by compression and ignition of a mixture of fuel and air. The linear motion of the one or more pistons is converted to rotational motion by connection of a connecting rod to a crankshaft. The rotation motion is then used, for example, for mechanical work or generation of electric power.
An alternative to the reciprocating internal combustion engine is the rotary engine. For example, the bladed turbine engine has been utilized in several industries, including for propulsion of aircraft and watercraft and for power generation. In contrast to the internal combustion engine, rotary engines replace the piston, connecting rod, and crankshaft with a rotor assembly, a rotating unit. Rotary engines operate differently than the internal combustion engine, but also result in rotational motion that is used, for example, for mechanical work or generation of electric power.
The internal combustion engine and the bladed turbine engine each suffer from respective shortcomings that are addressed by embodiments of the disclosure provided herein. These shortcomings include their complex construction and inherent inefficient operations.
Described herein is a boundary layer effect turbine that utilizes the phenomena of the boundary layer to drive a turbine impeller that is made of a plurality of spaced disks oriented along a rotatable shaft. As operating fluid is directed over surfaces of the plurality of disks of the boundary layer effect turbine, energy is transferred from the fluid to the disks as a result of the adhesive and viscous properties of the fluid. The boundary layer effect turbine directs the operating fluid in a radially-converging spiral, or vortical, path through narrow spaces between the plurality of disks and drives the shaft for the generation of electric power or for mechanical work. As explained further below, the boundary layer effect turbine of this disclosure provides embodiments that enhance the operation of the microturbine beyond the capabilities of the internal combustion engine or blade turbine.
In some embodiments, a modified boundary layer turbine is described that includes a housing having a fluid inlet port and a fluid outlet port; a central shaft, extending through the housing, the central shaft defining a central axis; and a plurality of annular disks within the housing, each of the disks being spaced apart from an adjacent disk by means, in some embodiments, of an airfoil shaped spacer, each spacer presenting a positive surface, which induces a near positive displacement of the fluid moving between the disks, each of the disks having an inner opening through which the central shaft extends and having an outer edge; wherein the outer edge of at least one of the of annular disks is tapered; wherein the plurality of annular disks is configured in the housing to transmit kinetic energy between at least one of the disks, as it rotates about the central shaft, and fluid introduced into the housing through the fluid inlet port, the transmission of kinetic energy resulting, at least in part, from a boundary layer formed at a surface of the at least one of the disks.
In some embodiments, at least one of the annular disks further comprises a tapered inner edge. In some embodiments, the fluid inlet port is along the central axis, and in some embodiments with the fluid inlet port along the central axis, the fluid outlet port is adjacent an outer edge of at least one of the plurality of disks. In some embodiments, the fluid outlet port is along the central axis.
In some embodiments, the modified boundary layer turbine further comprises a fluid heat exchanger in communication with the fluid outlet port and the fluid inlet port. In some embodiments, the modified boundary layer turbine further comprises a combustion chamber that directs fluid toward the fluid inlet port.
In some embodiments, rotation of the plurality of annular disks is configured to transmit kinetic energy from the rotating disks to the fluid. In some embodiments, the plurality of annular disks are configured to rotate upon transmission of kinetic energy from the fluid. In some embodiments, the central shaft is supported by at least one magnetic bearing, and in some embodiments, the central shaft is supported by at least one air bearing.
In some embodiments, a modified boundary layer turbine is described, comprising a housing having a fluid inlet port and a fluid outlet port; a central shaft, extending through the housing, the central shaft defining a central axis; and a plurality of annular disks within the housing, each of the disks being spaced apart from an adjacent disk, each of the disks having an inner opening through which the central shaft extends and having an outer edge; wherein the inner edge of at least one of the of annular disks is tapered; wherein the plurality of annular disks is configured in the housing to transmit kinetic energy between at least one of the disks, as it rotates about the central shaft, and fluid introduced into the housing through the fluid inlet port, the transmission of kinetic energy resulting, at least in part, from a boundary layer formed at a surface of the at least one of the disks.
In some embodiments, a modified boundary layer compressor is described that includes a housing having a fluid inlet port and a fluid outlet port; a central shaft, extending through the housing, the central shaft defining a central axis; and a plurality of annular disks within the housing, each of the disks being spaced apart from an adjacent disk by means of an airfoil shaped spacer, each spacer presenting a positive surface, which induces a near positive displacement of the fluid moving between the disks, each of the disks having an inner opening through which the central shaft extends and having an outer edge; wherein the outer edge of at least one of the of annular disks is tapered; wherein the plurality of annular disks is configured in the housing to transmit kinetic energy between at least one of the disks, as it rotates about the central shaft, and fluid introduced into the housing through the fluid inlet port, the transmission of kinetic energy resulting, at least in part, from a boundary layer formed at a surface of at least one of the disks.
Some embodiments describe a modified boundary layer compressor, comprising a housing having a fluid inlet port and a fluid outlet port; a central shaft, extending through the housing through the inlet and outlet ports, the central shaft defining a central axis; a plurality of annular disks within the housing, each of the disks having a face and being spaced apart from an adjacent disk such that the faces of the disks are substantially parallel; wherein each of the disks has a modified outer edge, and an inner opening through which the central shaft extends; wherein the plurality of annular disks is configured in the housing to transmit kinetic energy between at least one of the disks, as it rotates about the central shaft, and fluid introduced into the housing through the fluid inlet port, the transmission of kinetic energy resulting, at least in part, from a boundary layer formed at the face of at least one of the disks; and a plurality of elongate, arcuate elevations extending along the face of at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the central axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region.
In some embodiments, at least one of the annular disks further comprises a tapered inner edge. In some embodiments, the fluid inlet port is along the central axis, and in some embodiments with the fluid inlet port along the central axis, the fluid outlet port is adjacent an outer edge of at least one of the plurality of disks.
Certain embodiments described herein provide a boundary layer compressor, comprising a housing having a fluid inlet port and a fluid outlet port; a central drive shaft, extending through a central portion of the housing, the central drive shaft defining a central axis; a plurality of annular disks, within the housing, arrayed along and coupled to the central drive shaft; wherein each of the plurality of the annular disks has a front face and a rear face and is positioned along the central axis such that a plurality of substantially parallel annular spaces is defined between adjacent faces of the plurality of the annular disks; wherein the plurality of the annular disks define a cylindrical space located central to inner edges of the annular disks, the cylindrical space containing the central drive shaft; a blade member extending, in the cylindrical space, from the central drive shaft toward the inner edges of the annular disks, the blade member further extending helically about the central axis; wherein, during rotation of the central drive shaft, fluid located in the annular spaces is drawn in the direction of rotation in a boundary layer within the annular spaces; and wherein, during rotation of the central drive shaft, fluid in the cylindrical space is received along the cylindrical space from the fluid inlet port and directed radially outwardly through the annular spaces.
Some embodiments described herein provide a disk compressor assembly, comprising a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks defining a cylindrical space extending through a center portion of the annular disks and bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a blade member extending, in the cylindrical space, from the rotation axis toward inner edges of the annular disks, the blade member further extending helically about the rotation axis; wherein, during use, the plurality of annular disks rotates, and fluid is received into the cylindrical space, in a substantially axial direction, and the fluid flows between the annular disks, in a substantially radial direction, into the annular spaces.
Some embodiments described herein provide a disk compressor assembly, comprising a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks defining a cylindrical space extending through a center portion of the annular disks and bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a blade member extending, in the cylindrical space, from the rotation axis toward inner edges of the annular disks, the blade member further extending helically about the rotation axis; wherein, during use, the plurality of annular disks rotates, and fluid is received into the cylindrical space, in a substantially axial direction, and the fluid flows between the annular disks, in a substantially radial direction, into the annular spaces.
In some embodiments, a disk compressor assembly comprises a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks having an outer edge and defining a cylindrical space extending through a center portion of the annular disks that is bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a blade member extending, in the cylindrical space, from the rotation axis toward inner edges of the annular disks, the blade member further extending helically about the rotation axis; a fluid inlet located adjacent the outer edge of at least one of the plurality of annular disks and a fluid outlet located adjacent the cylindrical space; wherein, during use, fluid travels along a vortical flow path within at least one of the plurality of annular spaces from the fluid inlet to the cylindrical space, and then along a helical, axial flow path through the cylindrical space toward the fluid outlet.
Described herein are embodiments of a gas compressor based on the use of a driven rotor consisting of a plurality of flat disks utilizing the boundary layer phenomenon, which relies on the cohesive and viscosity properties of a gaseous fluid, combined with aerofoil shaped spacers between said disks to give a near positive displacement effect at high rotating speeds is presented herein. In using this method to compress inlet gas, the disk compressor efficiently achieves high compression ratios. The embodiments described herein include single, double, and multiple stage compression cycles. In the two stage versions, the gas flows radially outward accelerating the gas, converting velocity into pressure as the gas slows down in a circumferential diffuser. The gas is subsequently returned in a radially inward cycle, forcing the gas into a reduced volume at high speed to increase the pressure, after which the gas is allowed to expand into the recuperator volume that acts as a pressure sink. Multiple stages repeat the principles described above to obtain higher-pressure ratios.
In some embodiments, the fluid inlet port is along the central axis, and in some embodiments, the fluid inlet port is adjacent to an outer edge of at least one of the plurality of disks. Some embodiments provide that rotation of the plurality of annular disks is configured to transmit kinetic energy from the rotating disks to the fluid. In some embodiments, the plurality of annular disks are configured to rotate upon transmission of kinetic energy from the fluid. In some embodiments, the central shaft is supported by at least one magnetic bearing, and in some embodiments, the central shaft is supported by at least one air bearing.
Some embodiments describe a modified boundary layer turbine, comprising a housing having a fluid inlet port and a fluid outlet port; a central shaft, extending through the housing, the central shaft defining a central axis; a plurality of annular disks within the housing, each of the disks having a face and being spaced apart from an adjacent disk such that the faces of the disks are substantially parallel; wherein each of the disks has an outer edge, and an inner opening through which the central shaft extends; wherein the plurality of annular disks is configured in the housing to transmit kinetic energy between at least one of the disks, as it rotates about the central shaft, and fluid introduced into the housing through the fluid inlet port, the transmission of kinetic energy resulting, at least in part, from a boundary layer formed at the face of at least one of the disks; and a plurality of elongate, arcuate elevations extending along the face of at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the central axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region.
Some embodiments provide that the arcuate elevation comprises substantially an airfoil shape. In some embodiments, the arcuate elevation has a thickness equal to the space between adjacent disks, and in some embodiments, the arcuate elevation has a thickness greater than the boundary layer space between adjacent disks. Some embodiments provide that during rotation of the central shaft, the plurality of arcuate elevations directs fluid flowing across the face of the disk in a radially outward direction, and in some embodiments, during rotation of the central shaft, the plurality of arcuate elevations directs fluid flowing across the face of the disk in a radially inward direction. In some embodiments, the arcuate elevations present a surface, which induces a near positive displacement of the fluid moving between the disks, enhancing the mechanical efficiency of the boundary layer effect. In some embodiments, at least one of the arcuate elevations comprises a thickness equal to about twice the thickness of a laminar flow boundary layer of a fluid that flows into the housing from the fluid inlet port and across the face of at least one of the disks. In some embodiments, at least two of the disks are spaced about 0.6 mm apart, and in some embodiments, at least two of the disks are spaced about 1.2 mm apart.
Some embodiments provide that at least one of the arcuate elevations are integrally formed with at least one of the plurality of annular disks. In some embodiments, at least one of the arcuate elevations comprises a different material than does the at least one of the disks. In some embodiments, the central shaft is supported by at least one magnetic bearing, and in some embodiments, the central shaft is supported by at least one air bearing.
Certain embodiments described herein provide a boundary layer turbine, comprising a housing having a fluid inlet port and a fluid outlet port; a central drive shaft, extending through a central portion of the housing, the central drive shaft defining a central axis; a plurality of annular disks, within the housing, arrayed along and coupled to the central drive shaft; wherein each of the plurality of the annular disks has a front face and a rear face and is positioned along the central axis such that a plurality of substantially parallel annular spaces is defined between adjacent faces of the plurality of the annular disks; wherein the plurality of the annular disks define a cylindrical space located central to inner edges of the annular disks, the cylindrical space containing the central drive shaft; a blade member extending, in the cylindrical space, from the central drive shaft toward the inner edges of the annular disks, the blade member further extending helically about the central axis; wherein, during rotation of the central drive shaft, fluid located in the annular spaces is drawn in the direction of rotation in a boundary layer within the annular spaces; and wherein, during rotation of the central drive shaft, fluid in the cylindrical space is received along the cylindrical space from the fluid inlet port and directed radially outwardly through the annular spaces.
In certain embodiments of the boundary layer turbine, the blade member has width that extends from an interior edge of the blade member, located adjacent the central shaft, to an outer edge of the blade member that is closer to at least one of the plurality of the annular disks than is the interior edge; wherein the blade member is curved along its width. In some embodiments, the inner edge of at least one of the plurality of the annular disks is tapered. In some embodiments, an outer edge of at least one of the plurality of the annular disks is tapered. In some embodiments, the inner edge of at least one of the plurality of the annular disks is tapered. Some embodiments provide that at least one of the plurality of the annular disks comprises a plurality of elongate, arcuate elevations extending along the face of the at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the central axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region.
In some embodiments, the boundary layer turbine further comprises a plurality of blade members extending, in the cylindrical space, from the central drive shaft toward the inner edges of the annular disks, each of the plurality of blade members further extending helically about the central axis. In some embodiments, the central shaft is supported, during rotation, by at least one magnetic bearing, and in some embodiments, the central shaft is supported, during rotation, by at least one air bearing.
Some embodiments described herein provide a disk turbine assembly, comprising a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks defining a cylindrical space extending through a center portion of the annular disks and bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a blade member extending, in the cylindrical space, from the rotation axis toward inner edges of the annular disks, the blade member further extending helically about the rotation axis; wherein, during use, the plurality of annular disks rotates, and fluid is received into the cylindrical space, in a substantially axial direction, and the fluid flows between the annular disks, in a substantially radial direction, into the annular spaces.
In some embodiments, the blade member width extends from an interior edge of the blade member, located adjacent the rotation axis, to an outer edge of the blade member that is closer to at least one of the plurality of the annular disks than is the interior edge; wherein the blade member is curved along its width. In some embodiments, the inner edge of at least one of the plurality of the annular disks is tapered. In some embodiments, an outer edge of at least one of the plurality of the annular disks is tapered, and in some of these embodiments, the inner edge of the at least one of the plurality of the annular disks is tapered.
In certain embodiments, at least one of the plurality of the annular disks comprises a plurality of elongate, arcuate elevations extending along a face of the at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the rotation axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region.
In some embodiments, the disk turbine assembly further comprising a plurality of blade members extending, in the cylindrical space, from the rotation axis toward the inner edges of the annular disks, each of the plurality of blade members further extending helically about the rotation axis.
Some embodiments describe a disk turbine impeller, comprising a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks defining a cylindrical space extending through a center portion of the annular disks and bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a plurality of axial vanes that extend, within the cylindrical space, toward the inner edges of the annular disks from the rotation axis; wherein the axial vanes are oriented helically about the rotation axis.
Some embodiments provide that the blade member has a width that extends from an interior edge of the blade member, located adjacent the rotation axis, to an outer edge of the blade member that is closer to at least one of the plurality of the annular disks than is the interior edge; wherein the blade member is curved along its width. In some embodiments, the inner edge of at least one of the plurality of the annular disks is tapered. In certain embodiments, an outer edge of at least one of the plurality of the annular disks is tapered, and in some of these embodiments, the inner edge of the at least one of the plurality of the annular disks is tapered.
Some embodiments provide that at least one of the plurality of the annular disks comprises a plurality of elongate, arcuate elevations extending along a face of the at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the rotation axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region. In some embodiments, the disk turbine assembly further comprises a plurality of blade members extending, in the cylindrical space, from the rotation axis toward the inner edges of the annular disks, each of the plurality of blade members further extending helically about the rotation axis.
In some embodiments, a disk turbine assembly, comprises a plurality of substantially parallel annular disks, axially spaced along a rotation axis, the annular disks having an outer edge and defining a cylindrical space extending through a center portion of the annular disks that is bounded by inner edges of the annular disks; wherein the plurality of annular disks define a plurality of annular spaces between adjacent of the annular disks; and a blade member extending, in the cylindrical space, from the rotation axis toward inner edges of the annular disks, the blade member further extending helically about the rotation axis; a fluid inlet located adjacent the outer edge of at least one of the plurality of annular disks and a fluid outlet located adjacent the cylindrical space; wherein, during use, fluid travels along a vortical flow path within at least one of the plurality of annular spaces from the fluid inlet to the cylindrical space, and then along a helical, axial flow path through the cylindrical space toward the fluid outlet.
In some embodiments, the inner edge of at least one of the annular disks is tapered, and in some embodiments, the outer edge of at least one of the annular disks is tapered. In certain embodiments, the blade member has width that extends from an interior edge of the blade member, located adjacent the rotation axis, to an outer edge of the blade member that is closer to at least one of the plurality of the annular disks than is the interior edge; wherein the blade member is curved along its width.
In some embodiments, at least one of the plurality of the annular disks comprises a plurality of elongate, arcuate elevations extending along a face of the at least one of the disks, each of the arcuate elevations having a first region and a second region; wherein the first region of each of the arcuate elevations is located closer to the rotation axis than is the second region of the same arcuate elevation; and wherein each of the arcuate elevations tapers in width as it extends from the first region to the second region, such that a width of each of the arcuate elevations at its first region is greater than a width of the same arcuate elevation at its second region. In some embodiments, the disk turbine assembly further comprises a plurality of blade members extending, in the cylindrical space, from the rotation axis toward the inner edges of the annular disks, each of the plurality of blade members further extending helically about the rotation axis.
Some embodiments described herein provide a high speed permanent magnet starter generator which is mounted on the same shaft as other rotating assemblies. Some embodiments provide for the starter generator to be water cooled by water having a temperature lower than the ambient temperature in order to reduce the compressor inlet air temperature and enhancing compressor efficiency. In some embodiments, the casing of the starter generator may be provided with extended surfaces or fins to facilitate heat exchanging.
Some embodiments described herein provide a high speed hydrodynamic speed reducer that comprises a housing defining an internal chamber with a central axis; a cylindrical drive element within the internal chamber, the drive element being aligned along the central axis and having a helical recess along an outer surface of the drive element that defines a fluid drive flow path, the drive element being configured to couple with a rotatable speed reducer input; a driven element within the internal chamber, the driven element being aligned along the central axis and having a cylindrical bore with an internal surface having a helical recess that defines a fluid driven flow path, the driven element being configured to couple with a rotatable speed reducer output; a tubular divider element within the internal chamber and aligned along the central axis, the divider element having a first end and a second end and being positioned between the outer surface of the cylindrical drive element and the internal surface of the driven element; and operating fluid within the internal chamber, the fluid drive flow path, and the fluid driven flow path; wherein rotation of the speed reducer output is achieved by rotating the speed reducer input, which rotates the drive element and drives the operating fluid in a first axial direction along the fluid drive flow path, around the first end of the tubular divider, in a second axial direction along the fluid driven flow path, rotating the driven element, around the second end of the tubular divider, and into the fluid drive flow path.
Some embodiments include a combustor, for a boundary layer turbine, that includes a primary venturi burner, at least one secondary venturi burner, and a controller that directs flow of fluid through the primary venturi burner, the at least one secondary venturi burner, and through a passage that is not through a burner.
Some embodiments provide that the rotatable speed reducer input is supported by an air bearing, and some embodiments provide that the rotatable speed reducer input is supported by a magnetic bearing. In some embodiments, an operating fluid outlet, through which operating fluid is directed to an external oil cooler. In some embodiments, the cylindrical drive element comprises a plurality of helical recesses along the outer surface that defines a plurality of fluid drive flow paths. In some embodiments, the cylindrical bore of the driven element comprises a plurality of helical recesses along the internal surface that defines a plurality of fluid driven flow paths. In some embodiments, the helical recess along the outer surface of the drive element and the helical recess along the internal surface of the driven element are arranged such that rotation of the cylindrical drive element in a first rotational direction results in rotation of the driven element in a second rotation direction that is opposite the first rotation direction. In certain embodiments, the operating fluid comprises a synthetic oil with spherical inorganic nanoparticle properties that cause the oil to stay cool without loosing its lubricity. In some embodiments, the drive element is configured to couple with the rotatable speed reducer input by a magnetic drive. In some embodiments, the rotatable speed reducer input rotates the drive element through a magnetic drive.
A general architecture that implements the various features of the disclosure will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the disclosure and not to limit the scope of the disclosure. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements.
The boundary layer effect turbine described herein has several advantages over the internal combustion engine and the blade turbine. The internal combustion engine is a complex system that has several moving parts that are arranged about a rotating crankshaft. While the internal combustion engine has been used for many purposes in many industries, the complex construction presents significant maintenance complications. Additionally, the reciprocating motion between various components of the internal combustion engine (e.g., the piston within the cylinder) results in the generation of heat caused by the friction between parts. The heat results in losses that decrease the efficiency of the internal combustion engine.
Similarly, the blade turbine is also plagued with complications arising from its principle of operation. Cavitation occurs as the operating fluid engages the blades moving at extremely high speeds. This damages the blades and presents different, but significant, maintenance complications, such as requiring replacement or resurfacing of the turbine blades. Additionally, the blades rotate at near sonic speeds and create turbulent air flow through the turbine, resulting in inherently noisy operation. The distances between turbine blades also result in a large percentage of the fluid not making contact with the blades to impart its kinetic energy to the blades, resulting in a significant loss in efficiency.
The boundary layer effect turbine provides a single rotation assembly that operates to compress the operating fluid prior to combustion and utilizes the inherent adhesion and viscosity qualities of the fluid to drive the turbine. The total fluid flow is divided into extremely narrow segments, each segment being twice the size of the boundary layer at the disk surface, so as to maximize the transfer of kinetic energy at molecular level to the surface of the disk. Described herein are embodiments of the boundary layer effect turbine that builds upon these advantages and further enhances the operational efficiency of the boundary layer effect turbine.
The boundary layer effect turbine operates on properties of the operating fluid. All fluids, including a gaseous fluid, possess the two properties of viscosity and adhesion, which causes the molecules of the fluid to “stick” to the surface of the disks in a boundary layer interfacing with the body surface. At that interface, the fluid flow approaches zero relative speed to the surface, and the boundary layer is a transitional area extending from the body surface into the fluid. At the body surface the flow of the fluid with respect to the body surface approaches zero velocity, and the flow of fluid at a periphery of the boundary layer is where the flow of fluid is about 99% of the rate of the free-flowing fluid. Throughout the boundary layer, shear stresses of the fluid caused by the viscosity of the operating fluid, create a drag on the body surface as the fluid on one side is pulled in one direction by the free-flowing fluid and on the other side by adherence to the body surface. These shear stresses transfer kinetic energy of the flowing fluid to the body surface as a function of the fluid's viscosity.
As used herein, the term boundary layer is a broad term and is used with its ordinary meaning, which includes, without limitation, a transitional layer of fluid created when a fluid passes over a surface, the transitional layer having varying velocities ranging from a position adjacent or at the surface, where the velocity approaches zero with respect to the surface, to a position adjacent the free-flowing fluid, where the velocity of the fluid within the boundary layer approaches that of the free-flowing fluid. For example, in some embodiments, the boundary layer extends from the surface to a distance away from the surface at which the fluid's velocity ranges from about 93% to about 99% of the velocity of the free-flowing fluid. In some embodiments, the boundary layer extends from the surface, or a point adjacent the surface, to a distance away from the surface at which the fluid's velocity is less than about 93% or greater than about 99% of the velocity of the free-flowing fluid.
As used herein, the term free-flowing fluid is used is a broad term and is used with its ordinary meaning, which includes, without limitation, the fluid that is flowing with no or substantially no impedance caused by adjacent surfaces or structures. For example, the free-flowing fluid is that fluid that is not impeded by the stresses created by a boundary layer when fluid passes over a surface.
The boundary layer effect turbine utilizes the phenomena of the boundary layer to drive a rotor. As fluid is injected at high speeds directly over surfaces of a plurality of disks of the boundary layer effect turbine, energy is transferred from the fluid to the disks. The boundary layer effect turbine creates a vortex flow in a turbine expansion chamber by directing high velocity gas in a radially-converging spiral path through narrow spaces between a plurality of disks axially spaced along a rotating shaft. The fluid flow is introduced into the turbine expansion chamber near a periphery of the disks and is directed, in some embodiments, slightly incident to the plurality of disks. The fluid passes over one or more surfaces of the disk in vortical flow and is expelled through an aperture or apertures located near or at the center of the disks.
The disk edge 120 defines the outer periphery of the disk 102, and disk edges 120 of several disks 102 axially aligned along the shaft 110, as depicted in
Boundary layer theory dictates that the viscosity and adhesion properties of the operating fluid cause the fluid molecules to adhere to the smooth disk surfaces in the boundary layer at the body surface. In some embodiments, the disks are spaced to reduce or limit the amount of fluid escaping between adjacent boundary layers. In some embodiments, the volume of fluid passing between the disks consists substantially of only the sum of the volume of fluid in the adjacent laminar flow boundary layers. For this reason, it is desirable in some embodiments for the fluid to flow in a laminar path upon entering the space between the disks, and embodiments provided herein are directed to facilitate the creation of laminar flow boundary layers that improve or maximize the operational efficiency of the boundary layer turbine.
For example, in some embodiments, such as in some embodiments of boundary layer effect compressors, the disks are spaced along the shaft at a distance equal to about twice the width of the boundary layer. In these configurations, the boundary layer of each disk does not substantially interfere with the boundary layer of adjacent disks, and the distance between the boundary layers limits the flow of turbulent or free-flowing fluid between the disks. This facilitates in maximizing, increasing, or improving the transfer of kinetic energy between the disks and the operating fluid.
As depicted in
This boundary layer effect turbine has an extremely favorable horsepower-to-weight ratio when compared to any other internal combustion or turbine engines of comparable output. It also provides a high speed electric generator that can be configured to be coupled directly to a common shaft with the turbine, thus obviating expensive gear boxes. This disclosure further provides a boundary layer effect turbine that lends itself to scale-ups that may range from about 50 kWe to more than about 2000 kWe power outputs. In some embodiments, the boundary layer effect turbine disclosed herein can also generate energies below about 50 kWe or greater than about 2000 kWe.
With reference to
As depicted in
A recuperator 220 is provided in line with the compressor 210 to utilize exhaust heat from spent operating fluid, or exhaust, by preheating the operating fluid before the operating fluid passes through a combustor 225 or solid oxide fuel cell. In some embodiments, the recuperator 220 can provide a crossing flow path of incoming fluid, or fluid coming from the compressor 210, and outgoing fluid, or spent fluid to transfer energy from the spent fluid to the incoming fluid. In some embodiments, the recuperator 220 can provide a double cross flow path, in which the incoming fluid crosses paths, through different channels or pathways, with the outgoing fluid twice while flowing through the recuperator 220. This double counter (cross) flow path can enhance the transfer of energy between the outgoing fluid and the incoming fluid, and can increase the operation efficiency of the turbine 200 by preheating the incoming fluid prior to the combustion stage.
The fluid is introduced into the combustor 225, or solid oxide fuel cell, to provide heat to the operating fluid. In some embodiments, the combustor 225 includes a plurality of venturi burners with an adjustable air bypass control ring. The combustor 225 preferably operates to mix fuel, or some combustible content, with the operating fluid, and to ignite the fuel to input energy into the operating fluid.
From the combustor 225 or solid oxide fuel cell, the hot operating fluid is directed through a nozzle directed into a turbine expander 230. The pressurized and heated operating fluid is introduced into the turbine expander 230 along a perimeter of a disk assembly 100 that includes a plurality of boundary layer effect turbine disks 102. The fluid is directed substantially tangentially in the turbine expander 230 in a vortical flow path from an outer periphery of the disks 102, between the space between the disks 102, and through an exhaust port 105 toward the center of the disks 102. As the fluid flows in the vortical path along faces 115 of the disks 102, the fluid drives the disk assembly 100 and transfers kinetic energy to the disk assembly 100, generating a torque, or moment, about the central axis 125 of the shaft 110 extending through the turbine expander 230. The torque causes the disk assembly 100 and shaft 110, which is coupled with the disk assembly 100, to rotate.
The operating fluid is directed from the exhaust port 105 in the turbine expander 230 back into the recuperator 220. The recuperator 220 directs the flow of the exhaust fluid to cross paths with incoming fluid that has been compressed by the compressor 210. The recuperator 220 preferably separates the flow of the exhaust flow and the incoming fluid by a plurality of thin walls that are configured to conduct heat from fluid on one side to fluid on the opposite side of the wall. As discussed above, and shown below with reference to the recuperator 220, the recuperator 220 can provide a double cross-flow path that enhances the heat transfer from the exhaust fluid to the incoming fluid. After passing through the recuperator 220, the exhaust fluid is discharged from the turbine 200. Although not depicted in
In some high-speed embodiments, the central shaft 110 can be supported by at least one magnetic bearing 300, and in some embodiments, the central shaft 110 is supported by at least one air bearing 300. In some embodiments, the shaft 110 may be supported by roller bearings 300. The turbine 200 can be fitted with airfoil or magnetic bearings 300 to facilitate operation and improve efficiency. Although embodiments of boundary layer effect turbines 200 can operate with mechanical roller bearings 300, operation with mechanical roller bearings 300 can increase maintenance and decrease both longevity of the turbine and efficiency, while limiting the rotating speed of the shaft to the capacity of the bearing 300.
Magnetic bearings 300 used in embodiments of boundary layer effect turbines 200 can be operated by permanent or electric magnets. In some embodiments, the electric magnets are powered by the turbine 200 during operation. Additionally or alternatively, the turbine 200 can include at least one air foil bearing 300. Air foil bearings 300 operate with the pressurized fluid flowing through the turbine 200 and can increase efficiency and operational longevity of the turbine, without limiting the rotating speed of the turbine 200. With magnetic and air bearings 300, the turbine 200 can be constructed with substantially only one moving part, the shaft 110, extending through the magnetic bearing 300 and the air foil bearing 300. This construction can decrease maintenance requirements and improve operational efficiency.
The shaft 110 extends through the compressor section 260, where two compressor assemblies 305, or compressor impellers, are depicted in
The compressor section 260 can include expanded portions that function as a diffuser to allow the fluid to decrease velocity and increase pressure. The compressed fluid can be scavenged, or drawn, from the diffuser, or expanded portion, into a second stage, where the disk assemblies 305 are configured to have thicker protrusions, or spacers, between the disks 102. As discussed in more detail later, these spacers, or blades, are shaped to present a larger cavity at the center of the disk 102 that at the periphery, to reduce any pinching effect that could create a drop in pressure. The larger cavities between the disks 102 of the assembly 305 can permit the fluid to move freely toward the center of the disk 102 to counteract the centrifugal force imposed by the rotating disk 102, which could contribute to a stalling condition.
In a third compressor 210 stage, the fluid is directed outward again in a similar manner as in the first stage. The compressed fluid is then directed into a plurality of thin-walled tubes of the recuperator section 270 to receive heat from cross-flowing heated fluid. After being preheated by the cross-flowing heated fluid, the operating fluid is directed into at least one or more combustion sections 280, where the fluid is further heated by a combustor 225 before being introduced into the turbine expander section 290. After the fluid is expanded in the turbine expander section 290, the fluid is directed through the recuperator section 270 to preheat incoming compressed fluid from the compressor section 260 through a double cross-flow path. After preheating the cooler compressed fluid, the exhaust fluid is then directed through exhaust ports 295.
Illustrated in
Although
In some embodiments, although not depicted in
In some embodiments, the diameter of the disks 102 within each compressor impeller 305 are the same, but the diameter of each compressor impeller 305 is different. For example, a first compressor impeller 305 can have a first diameter, and a second compressor impeller 305 can have a second diameter. In some embodiments, the first diameter is greater than the second diameter, and in some embodiments, the second diameter is greater than the first diameter.
The same principle of utilization of the fluid's viscosity and adhesion properties are implemented to draw the operating fluid through the compressor 210 by driving the compressor impellers 305. However, when the compressor impellers 305 are in operation, the fluid flows into the inlet 350 at a middle portion of the disks 102. In the first compression chamber 355, or volute, surrounding the first of the two depicted compressor impellers 305, the working fluid is directed to the center of the second compressor impeller 305, as indicated by arrow 358. The working fluid passes through the compression fluid inlets 360 of the second compressor impeller 305 and is driven to a central entrance of the recuperator 220.
In some embodiments, the fluid inlet 350 of the compressor impellers 305 have a decreasing volume along the flow path of the operating fluid. In some embodiments, the decreasing volume directs the fluid from the compressor inlet 350 to spaces between the compressor disks 102. In some embodiments, the decreasing volume is, in part, created by a semi-frustoconical member 365 within the compressor impeller inlet 350. The member 365 can include one or a plurality of vanes 366 (
Embodiments of the boundary layer compressors 210 described herein can be used in conjunction with the boundary layer turbine 200, or can be used for other purposes that are independent of the turbine 200. For example, the compressors 210 are suitable as small lightweight compressors and as very large industrial compressors for new applications, such as carbon dioxide compression for subsequent underground sequestering in aquifers. These embodiments describe new high efficiency gas compressors that operate at high speed, in which improved compression performance and functional durability are attained by the use of boundary layer principles, which, as described elsewhere herein, utilize the adhesive and viscosity properties of gaseous fluids employed, combined with specially shaped spacers to provide efficient compression of said fluids. Compressors so constructed are particularly useful for compression of air, carbon dioxide, refrigerants, steam, hydrocarbons, and other compressible fluids in either freestanding mode or as integrated elements of turbo-machinery.
Described herein are embodiments of simple, highly efficient and inexpensive gas compressors 210 for a wide variety of gas compression applications. Gas compression uses considerable amounts of energy, and applications and embodiments of the compressors described herein can provide significant efficiency improvements over other designs. In the case of microturbines, it has been found that in some designs, the compressor section 260 can use more than about 50% of the gross power developed by the turbine. The embodiments of compressors 210 described herein offer increased efficiency, reduced operating costs, reduced first cost for the equipment, reduced maintenance costs, and are able to operate at very high shaft 110 speeds so as to be able to operate off the same shaft 110 as a turbine 200 without the use of a gear box.
In particular, several distributed power generators, powered by microturbines, demand a much greater level of overall efficiency in order to compete with grid power. The application of microturbines for automotive and marine craft application can benefit from a compact compressor capable of operating at rotating speeds in the range of 20,000 to 150,000 rpm, which are the normal operating speeds of microturbines. The important advantages of the gas compressors described herein can be employed for micro turbine applications as well as for major industrial scale applications, and the myriad of sizes between.
Illustrated in
In some embodiments, the spacers 420 of the compressor disks 102 include one or more, or at least one, elevated vane 420, as shown in
Aerofoil sections can be used in centrifugal rotors, such as in vane pumps and compressors, and the aerofoil sections can be integrally formed on the disk 102 or affixed to the disk 102 through two or more locating holes 425 to obviate welding spacers to the disks. Although some embodiments of the present disclosure are configured to accommodate aerofoil sections that are welded, some embodiments are configured without welding, as welding can create stress raisers that can cause the disks to fail because of the forces involved when the impeller 305 spins at speeds from about 20,000 rpm to about 100,000 rpm. Utilization of only one fixing point without welding can cause the spacer 420 to swing open at high temperatures and under full load conditions should the disks 102 start to expand or distort. In some embodiments, washer shaped spacers can be used to separate the disks 102.
In some embodiments, ambient air is drawn around the starter/generator into the inlet vanes 365 at the inlet port 350 of the compressor 210 and distributed evenly into the narrow spaces between the disks 102, causing air to move radially outwards in an outward spiral, to be discharged at the periphery into a diffuser 430 where the velocity is reduced causing the gas to present at higher pressures than ambient. The air is then directed to the inlet of a second compressor and is compressed as discussed above. Upon discharge of the air into a second diffuser, the air is then directed to an inlet of a recuperator 220.
In some embodiments, the compressor impeller 305 can have a first plurality of disks 470 that operate to direct fluid from the inner edge 465 of the disks 102 to the outer edge 120 of the disks 102 and a second plurality of disks 480 that operate to direct fluid from the outer edge 120 of the disks 102 to the inner edge 465 of the disks 102. In some embodiments, the first and second plurality of disks 470, 480 can be separated by a central disk 490, which also operates to separate the fluid inlet 350 from a fluid outlet 352, as shown in
Certain embodiments include a plurality of disk stacks 470, 480, one stack 470 forming a first phase 510 of the compressor 210, the second stack 480 comprising a second phase 520 of the compressor 210, both stacks 470, 480 being mounted on a common shaft 110 with a sturdy dividing disk, or central disk 290, between the stacks 470, 480 and onto which fixing pins 525, which hold the disks 102 together as a single composite stack, are affixed.
In some embodiments, the disks 102 have elevated vanes 420, in of the first phase 510, that have widths that extend from an inner region adjacent the interior edge 465 of the disk 102, which is located near the rotation axis 530, about which the disks 102 rotate, to a region adjacent the outer edge 120 of the blade member 102. In some embodiments, the blade member, spacer blade, or elevated vane 420, is curved along its width so as to gently drive the fluid along a leading edge 461 from the inner region adjacent the interior edge 465 toward the outer edge 120 of the disk 102.
In some embodiments, the curvature of the spacer blades 420 mounted between the disks 102 of the second phase 520 face in the opposite direction as the spacers 420 of the first phase 510, acting, when the shaft 110 is rotated, to drive the fluid towards the shaft 110 in a decreasing space to further increase its pressure.
In some embodiments, the member 365, or central boss, which extends axially along the rotor or shaft 110 from the central dividing disk 490, is shaped to compensate for the reducing volume of gaseous fluid entering the central stacks of the first phase 510. For example, as depicted in
For example,
The diffuser vanes 540 are preferably configured to move fluid through the diffuser 430, from the first plurality of disks 470, to the second plurality of disks 480. In some embodiments, the diffuser vanes 540 are configured to direct the movement of air from the diffuser 430 toward the second plurality of disks 480. In some embodiments, the diffuser vanes 540 extends radially from the compressor impeller 305, and in some embodiments, the diffuser vanes 540 are coupled to the central disk 490.
In some embodiments, the diffuser vanes 540 are configured to be stationary with respect to the rotating disks 102. For example, the diffuser vanes 540 can extend into the diffuser volume from the compressor housing 359 (
As depicted in
For example, a leading edge 461 of the elevated vanes 420 of the first plurality of disks 470, as illustrated in
In some embodiments, at least one of the arcuate elevations, spacers, or elevated vanes 420, comprises a different material than does at least one of the disks 102. The selection of materials and the mechanical design of rotating components in the embodiments envisioned herein limit or reduce use of excessive quantities or weights of materials, but the design provides the strength where desired in the rotor, commensurate with the centrifugal forces acting on the rotating components.
In some embodiments, as illustrated in
In some embodiments, the diffuser 430 is shaped in such a way that the fluid is re-injected tangentially into the spaces between the disks 102, where it is driven radially inward mostly by the reaction force against the spacers 102, which act as vanes to direct the fluid toward the central outlet port 352. The diffuser vanes 540 in the diffuser 430 change the direction of the moving fluid from one phase to the next and, in some embodiments, further slows down the moving fluid to allow the aerofoil spacers 420 to draw in the fluid, or gas, and to drive it inwards. Centrifugal force counteracts the movement of the fluid inwards, thus increasing the pressure of the fluid, with centrifugal force acting radially outwards and with positive displacement force acts inwards. Simultaneously, the fluid passes through a decreasing volume, which further increases the pressure. In some embodiments, to avoid a stalling situation, the spaces between the second plurality of disks 480, or second phase of disks 520, are larger than the spaces between the first plurality of disks 470, or first phase of disks 510, causing the gaseous fluid to travel more freely through the turbulent zone, somewhat away from the laminar flow zone (as shown in
In some embodiments, the shape of the elevated vanes 420 can be adjusted to align closely with the flow of fluid through the compressor 210 when the turbine 200 is operating under normal operating conditions. In some embodiments, adjustments to the vanes can be made to slightly impose a displacement force on the fluid flowing past the vanes 420.
Depicted in
Some embodiments of a method of aligning the vanes 420 includes identifying an unimpeded flow of fluid over a disk 102 of the turbine 200 at normal operating conditions and identifying a desired alignment of an edge of a vane 420 that will impose a displacement force upon the fluid. In some embodiments, the method can further include adjusting the vane 420 to the desired alignment. In some embodiments, these methods are used to adjust the vanes 420 in at least one of the compressor 210 and the turbine expander 230.
Some embodiments include a gas bypass arrangement, which can permit part of the compressed gas output between phases or stages to be vented as desired, while maintaining high rotating velocity when utilizing the compressor drive apparatus and while maintaining minimal output loads.
Parameters that can determine the performance characteristics of a disk turbine design, for example, a two stage disk turbine design, include a diameter of compressor and turbine disks 102, the rotor speed, the gaps between the disks 102, the number of disks 102, the shape of the elevated spacers 420, and the inlet nozzle (directing fluid into the turbine expander 230) design. Embodiments described herein provide theoretical and empirical parameters that are configured to optimize operational performance of the boundary layer effect turbine.
In some embodiments, the compressor 210 includes compressor disks 102 having a diameter of about 25 cm. In some embodiments, the compressor 210 can have disks 102 with diameters ranging from about 20 cm to about 30 cm. Some embodiments include compressors 210 with disks 102 having diameters ranging from about 15 cm to about 35 cm, and some embodiments include compressors 210 with disks 102 having diameters less than about 15 cm or greater than about 35 cm.
In some embodiments, a compressor impeller 305 can include about 24 disks 102. In some embodiments the compressor impeller 305 can have from about 18 disks 102 to about 30 disks 102, and in some embodiments, the compressor impeller 305 can have from about 12 disks 102 to about 36 disks 102. In some embodiments, the compressor impeller 305 can have less than about 12 disks 102 or greater than about 36 disks 102.
In some embodiments, the number of compressor disks is dependent upon the number of turbine disks, or the number of compressor disks is determined by a ratio with respect to the turbine disks. For example, in some embodiments the ratio of compressor disks to turbine expander disks is about 2.5:1. In some embodiments, the ratio ranges from about 2.3 and about 2.7 compressor disks to each turbine expander disk, and in some embodiments, the ratio ranges from about 2.0 and about 3.0 compressor disks to each turbine expander disk. In some embodiments, the ratio is less than about 2.0 or greater than about 3.0 compressor disks to each turbine expander disk. For example, in some embodiments, the ratio is about 3.5, about 4.0, about 5.0, about 7.5, and about 10.0 compressor disks to each turbine expander disk.
In some embodiments, the rotational speed of the compressor 210 is the same as that of the shaft 110, as driven by the turbine expander disks 102. In some embodiments, the rotational speed of the compressor is about 20,000 rpm. In some embodiments, the rotational speed of the compressor ranges between about 15,000 rpm and about 25,000 rpm. In some embodiments, the rotational speed of the compressor ranges from about 10,000 rpm to about 30,000 rpm. In some embodiments, the rotational speed of the compressor is less than about 10,000 rpm or greater than about 30,000 rpm. For example, in some embodiments, the rotational speed of the compressor can be about 40,000 rpm, about 50,000 rpm, about 75,000 rpm, and about 100,000 rpm. In some embodiments, the rotational speed of the compressor can be variable depending on the desired output of the turbine 200.
In some embodiments, the compressor disks 102 are spaced at a distance to enhance the efficiency of the compressor 210. In some embodiments, the compressor disks are spaced about 1.2 mm apart. In some embodiments, the compressor disks are spaced between about 1.1 mm and about 1.3 mm apart, and in some embodiments, the compressor disks are spaced between about 1.0 mm and about 1.4 mm apart. In some embodiments, the compressor disks are spaced less than about 1.0 mm or greater than about 1.4 mm apart. In some embodiments, the compressor disks are spaced a various distances apart depending on the desired flow characteristics through that portion of the compressor 210.
This disclosure provides further improvements on management of the operating fluid to reduce inherent losses as the fluid flow enters and exits the rotor, or impeller 305. In some embodiments, the inlet and exhaust ports 350, 352 or apertures 105 are configured to be a substantially annular shape concentrically oriented about the shaft 110, as illustrated in
In some embodiments, the disks 102 used in the impellers 305 have a cross-sectional profile with flat and abrupt outer edges, as depicted in
In some embodiments, as depicted in
The streamlined edges of the disks 102 allow the fluid to flow more freely between the narrow spaces between the disks 102 in a laminar flow pattern, thus imparting the molecular energy of the fluid to the disk surface and reducing slippage between the fluid and the disk surface as a consequence of turbulent flow. The boundary layer effect turbine 200 described in this disclosure enables the fast-moving fluid to transfer more gently into and out of the impellers 305, thus avoiding turbulent flow and yielding higher efficiencies.
After expanding the hot fluid via the expander 230 and turbine impeller, the spent gas is discharged into the recuperator 220 to preheat incoming compressed fluid and is then discharged via a tangential exhaust 235 and may then be used as an oil free heating medium for other applications.
Compressed air enters a first concentric passage 660, from the compressor 210, and flows around the bearing capsule 630, flowing towards the hot side in a counter flow mode. This flow keeps the bearing capsule 630 cool, and the compressed fluid starts to accept heat from the hot outer passage 620 before the fluid is distributed to the voids between the tubes 650 by means of a multitude of inlet ducts 665. The compressed air is allowed to travel, in a second cross-flow path, at a reduced speed through the stainless steel wool 660, or other transfer medium, around the tubes 650, allowing for ample time to absorb the heat from the thin walled tubes 650. It is conservatively estimated that the recuperator 220 can recover more than about 80% of the heat from the counter flowing exhaust gas. In some embodiments, the recuperator 220 recovers between about 70% and about 90% of the heat from the counter flowing exhaust gas. In some embodiments, the recuperator recovers greater than about 90% of the heat from the counter flowing exhaust gas. In some embodiments, the recuperator 220 recovers between less than about 70% of the heat from the counter flowing exhaust gas. In some embodiments, the recovery of heat is determined by a change in temperature of both the exhaust and compressed fluid from when the fluid enters the recuperator and the temperature of the fluid leaving the recuperator in the exhaust and the temperature of the fluid leaving the recuperator toward the combustion chamber. In some embodiments, a recovery of 70% corresponds to a 70% reduction in temperature difference between the compressed fluid and the exhaust fluid from the time the fluid enters the recuperator until the time the fluid exits the recuperator.
In some embodiments, as depicted in
In some embodiments, the turbine expander impeller 700, or turbine impeller 700, includes a plurality of annular disks 102, and each of the disks have a face 115. The disks 102 are preferably spaced apart from an adjacent disk, such that planes containing the surfaces or faces 115 of adjacent disks 102 are substantially parallel. In some embodiments, each disk 102 has an outer edge 120 and an inner opening 465, through which the central shaft 110 extends. As depicted in
The arcuate elevations 420 preferably include a first region 750 and a second region 760. The first region 750 is located closer to the shaft 110, or central axis 125 of the shaft 110, than is the second region 760 of the same arcuate elevation 420. In some embodiments, the arcuate elevation 420 tapers in width as it extends from the first region 750 to the second region 760, such that a width of each of the arcuate elevations 420 at its first region 750 is greater than a width of the same arcuate elevation at its second region 760.
Accordingly, when the disks 102 are being used as a turbine impeller 700, as depicted in
As shown in
The flow of fluid along the surface of the faces 115 of the disks 102 combines with the reaction force against the aerofoil spacers 420 and induces the disks 102 to move with the fluid in accordance with the boundary layer effect described above. When a load is applied, an amount of slip has a tendency to occur without the airfoil shaped spacers 420 and has been found to be proportional to the workload. The greater the load, the more direct the route taken by the expanding gas from the outer edge 120 to exit 105, until stalling conditions become manifest. The introduction of aerofoil shaped spacers 420 assists in maintaining a constant flow pattern to maintain a constant speed and torque and to reduce the amount of slip.
When using circular spacer washers, up to 94% energy conversion efficiency can be achieved in a no load condition, reducing, with increase load, until a stalled condition is reached. For a well designed expander 230, the energy conversion efficiency is determined (Btu in the fuel is converted to kWe) by the shape and size of the inlet nozzle 744 and thus the velocity of the entering gas. Under no load conditions, the disk tip speed (or the speed of the outer edge 120 of the disks 102) approaches the fluid velocity, according to boundary layer theory, the geometry of the inlet and outlet edges 120 of the disks 102, the space between the disks 102, the number and size of the disks 102, the shape of the spacers 420, and the operating speed of the disk impellers 700 and the angle of attack (or orientation) of the aerofoil shaped spacers 420.
Although the compressor 210 also uses the boundary layer effect mechanism, a compressor 210 using boundary layer drag theory operates differently from a turbine expander 230. In the case of the compressor 210, the driven surfaces move at high speeds over low speed ambient air. Centrifugal force forces the fluid to the edge 120 of the disk 102 and creates a low pressure region between the disks 102 with the ejection of the air in the turbulent flow region slightly away from the disk surface 115. As is the case with the turbine, the relative velocity of the gas and surface approaches zero at the surface interface (laminar flow region). It is therefore more difficult to rapidly transfer the air in the laminar flow region. A compressor 210 therefore displaces the air in the turbulent flow region, directly adjacent to the laminar flow region at the surface. Slightly wider spaces between disks 102 are therefore needed for compressors 210 than for turbine expanders 230.
Upon leaving the vaned axial port 770 of the turbine expander 230 at the center of the impeller 700, the fluid is directed back to the recuperator 220 where it flows inside the creep-resistant thin-walled stainless steel tubes 650 in a double counter-flow mode and in close proximity to the cooler compressed air in substantially parallel paths inside the voids between the tubes 650. The entire flow path of the fluid is able to retain a streamlined spiral shape from the compressor inlet 350 through the turbine 230 through the recuperator 220 to the exhaust outlet 235.
As discussed above, parameters that influence the performance characteristics of a disk turbine design, for example, a two stage disk turbine design, include a diameter, of compressor and turbine disks 102, the rotor speed, the gaps between the disks 102, the number of disks 102, the shape of the spacers 420, and the inlet nozzle 744 design. In some embodiments, the turbine 200 includes turbine impeller disks 102 having a diameter of about 25 cm. In some embodiments, the turbine impeller 700 can have disks 102 with diameters ranging from about 20 cm to about 30 cm. Some embodiments include a turbine impeller 700 with disks 102 having diameters ranging from about 15 cm to about 35 cm, and some embodiments include turbine impellers 700 with disks 102 having diameters less than about 15 cm or greater than about 35 cm.
In some embodiments, the turbine impeller 700 can include about 60 disks. In some embodiments the turbine impeller 700 can have from about 50 disks to about 70 disks, and in some embodiments, the turbine impeller 700 can have from about 40 disks to about 80 disks. In some embodiments, the turbine impeller 700 can have less than about 40 disks or greater than about 80 disks.
In some embodiments, the number of turbine impeller disks 102 is dependent upon the number of compressor impeller disks 102, or the number of compressor disks 102 is determined by a ratio with respect to the turbine disks 102, as discussed above. For example, in some embodiments the ratio of compressor disks to turbine expander disks is about 2.5:1.
In some embodiments, the operational speed of the turbine impeller 700 is the same as that of the shaft 110. In some embodiments, the rotational speed of the turbine impeller 700 is about 20,000 rpm. In some embodiments, the rotational speed of the turbine impeller 700 ranges between about 15,000 rpm and about 25,000 rpm. In some embodiments, the rotational speed of the turbine impeller 700 ranges from about 10,000 rpm to about 30,000 rpm. In some embodiments, the rotational speed of the turbine impeller 700 is less than about 10,000 rpm or greater than about 30,000 rpm. For example, in some embodiments, the rotational speed of the turbine impeller 700 can be about 40,000 rpm, about 50,000 rpm, about 75,000 rpm, and about 100,000 rpm.
In some embodiments, the turbine impeller disks 102 are spaced at a distance to enhance the efficiency of the turbine impeller 700. In some embodiments, the turbine impeller disks 102 are spaced about 0.6 mm apart. In some embodiments, the turbine impeller disks 102 are spaced between about 0.4 mm and about 0.8 mm apart, and in some embodiments, the turbine impeller disks 102 are spaced between about 0.2 mm and about 1.0 mm apart. In some embodiments, the turbine impeller disks 102 are spaced less than about 0.2 mm or greater than about 1.0 mm apart.
The flow of compressed air is calculated as a positive displaced volume of the active turbulent space between the disks. For maximum efficiency in the turbine expander 230, the distance between the total boundary layers, i.e., the laminar flow plus the turbulent flow regions, should be zero (represented by the dotted rectangle below point B in
The boundary layer effect turbine 200 described herein can be operated on any credible form of combustible liquid or gaseous fuels, as long as the burner arrangement and fuel air ratio are properly designed to match the specific fuel. It can further be utilized with natural sources of heat, such as a geothermal source.
The boundary layer effect turbine 200, microturbine, or DiskTurbine© can also run as an unfired turbine by sharing the same fuel supply with fuel cells, or it can be driven by the pressurized off gases of solid oxide fuel cells. In such applications, the combined power conversion efficiency could exceed 70%. The boundary layer effect turbine can operate with various fuel cell technologies and fuel types, including but not limited to the following: bio-diesel, ethanol, natural gas, liquid propane gas, kerosene, diesel or any other gaseous or liquid hydrocarbon, coal bed methane or methane from municipal waste dumps (fuels are not universally interchangeable with the same burners) and operates on renewable plant alcohol and oils or straight hydrogen. For coal fired applications, especially when poor quality coals are used, the coal can be fired in a fluidized bed combustor (FBC). Lime is added to neutralize the sulfur to improve the chimney stack emission. Heat resistant heat exchanger tubes are inserted in the firing zone of the FBC and internally pressurized by the compressed air from the compressor. The heated compressed air is allowed to expand in the turbine to generate power. The clean hot exhaust air is then used for space heating, process heating, or steam generation for further power generation and/or HVAC.
Illustrated in
Provided in this disclosure is a high-speed hydrodynamic speed reducer 1000 (“HSR”), which is aimed at operating with the microturbine to provide a high-speed gearless speed reducers for microturbines in the size range from about 80 hp to about 300 hp. For example, hybrid passenger vehicles may operate within this range.
The HSR 1000, illustrated in
The volute 1020, sleeve 1030, and drive 1010 are preferably encased in a casing 1040 that can include a first portion 1045 and a second portion 1050. The first and second portions 1045, 1050, when coupled together form a hollow interior, which is configured to contain the volute 1020, sleeve 1030, drive 1010, and operating oil. Each of the first and second portions 1045, 1050 preferably accommodate coupling with a shaft. In some embodiments, the first portion 1045 can include an aperture 1047 through which an output shaft 1110 can extend. The output shaft 1110 can be supported by a boss 1048 that contains a supporting bearing 1049. In some embodiments, the second portion 1050 can be configured to couple with embodiments of the turbine 200 described herein. In some embodiments, the second portion 1050 can include a plurality of fins 1051 that disperse heat from the HSR 1000 and direct fluid flow into a compressor 210.
The helix drive 1010 conveys a specially designed synthetic oil axially along the thread cavity of the inside portion 1015, the oil being discharged into the multiple spiraled volutes of an outer element over the sleeve 1030, which is a concentric tubular divider. Four or more spiral shaped volutes of the outer element has only one spiral turn from end to end. A constant volume of fluid, which is supplied by the volute 1020, which operates as a worm drive, is divided equally between the number of spiral volutes, each volute having a similar cross sectional area as that of the volute 1020.
Should the combined cross sectional area of the drive and driven elements be the same, the reduction ratio would have been 1:1. By increasing the number of spiral turns as well as the number of spirals, a reduction ratio of N×S is achieved, where N=the number of turns and S=the number of spirals, due to the fact that the number of spirals of the driven element is increased, causing the fluid to travel slower through a combined cross sectional area which is now larger. It will be appreciated that a wide range of permutations is possible, depending on the specific application, but the reduction ratio is fixed for each permutation.
The reaction forces that are created are axial in nature. The drive element 1010 will tend to move to the opposite side the fluid would be traveling. Since the fluid is recirculated, it re-enters the drive element 1010 at the bottom of the drive element 1010 to balance that axial force. The same situation arises with the tubular divider, or sleeve 1030, which is being kept in an equilibrium position between the drive, or volute 1020, and driven elements 1010. The driven element 1010 will however tend to move axially towards the output shaft 1110. To counter that force, a slow speed thrust bearing may be fitted.
The output shaft 1110 is an inherent part of the driven element 1010. The bearing 1049 and seal cap, or boss 1048, keep the double thrust roller bearings in place. The driven element 1010 is shown with four spiraled volutes each with a single turn. The geared teeth at the skirt of the driven element 1010 act as an oil pump to drive a small percentage of the oil to an external oil cooler via a tangential outlet. The volute 1020 is depicted with a single spiral with three turns, followed by the concentric tubular divider, or sleeve 1030. The main casing is shown with its connecting fins 1051, which can also be structural members to support the HSR 1000 and the compressor.
In some embodiments, the speed reducer 1000 includes a housing defining an internal chamber with a central axis, a cylindrical drive element within the internal chamber, the drive element being aligned along the central axis and having a helical recess along an outer surface of the drive element that defines a fluid drive flow path, the drive element being configured to couple with a rotatable speed reducer input. The speed reducer can also include a driven element within the internal chamber, the driven element being aligned along the central axis and having a cylindrical bore with an internal surface having a helical recess that defines a fluid driven flow path. In some embodiments, the driven element is configured to couple with a rotatable speed reducer output. In some embodiments, a tubular divider element within the internal chamber and aligned along the central axis, the divider element can have a first end and a second end and being positioned between the outer surface of the cylindrical drive element and the internal surface of the driven element.
In some embodiments, the reducer 100 includes operating fluid within the internal chamber, the fluid drive flow path, and the fluid driven flow path, and rotation of the speed reducer output is achieved by rotating the speed reducer input, which rotates the drive element and drives the operating fluid in a first axial direction along the fluid drive flow path, around the first end of the tubular divider, in a second axial direction along the fluid driven flow path, rotating the driven element, around the second end of the tubular divider, and into the fluid drive flow path.
At the heart of the system lies a magnetic drive 1018, which drives a central element 1020, similar to a worm drive, and typically has three or more spiral turns of adequate thread diameter. In order to isolate the driven element from the high-speed shaft so as to eliminate the need for a complex dynamic sealing arrangement, a magnetic drive is used. This drive has the capability of transferring mechanical power through a non-magnetic sleeve, making it possible to transfer horsepower from one compartment to the adjacent one with out any physical contact.
In some embodiments, the turbine 200 and HSR 1000 can be used in connection with commercially available air conditioning systems 1100, such as that depicted in
Although embodiments of the disclosure have been described in detail, certain variations and modifications will be apparent to those skilled in the art, including embodiments that do not provide all the features and benefits described herein. It will be understood by those skilled in the art that the present disclosure extends beyond the specifically disclosed embodiments to other alternative or additional embodiments and/or uses and obvious modifications and equivalents thereof. In addition, while a number of variations have been shown and described in varying detail, other modifications, which are within the scope of the present disclosure, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the present disclosure. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the present disclosure. Thus, it is intended that the scope of the present disclosure herein disclosed should not be limited by the particular disclosed embodiments described above.
The present application is a §371 national phase application filing of Application No. PCT/US2008/088687, with an international filing date of Dec. 31, 2008, and which claims priority benefit from U.S. Provisional Application No. 61/018,089, filed Dec. 31, 2007, the entire contents of both of which are hereby incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2008/088687 | 12/31/2008 | WO | 00 | 11/24/2010 |
| Number | Date | Country | |
|---|---|---|---|
| 61018089 | Dec 2007 | US | |
| 61030917 | Feb 2008 | US |
