Unitary impeller and turbomachine including the unitary impeller

Abstract

A turbomachine includes a compressor housing and a turbine housing. One of the compressor housing and the turbine housing includes a first seal component. The turbomachine also includes a unitary impeller rotatable about an axis, including a first face having a plurality of turbine blades facing in a first direction, and a second face having a plurality of compressor blades facing in a second direction. One of the first face and the second face includes a second seal component configured to cooperate with the first seal component to establish a fluid seal between the compressor housing and the turbine housing. The turbomachine further includes a shaft rotatable with the unitary impeller and an electric machine configured to convert at least one of rotational motion of the shaft to electrical energy and electrical energy to rotational motion of the shaft.

Description

UNITARY IMPELLER AND TURBOMACHINE INCLUDING THE UNITARY IMPELLERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and all the benefits of U.S. Provisional Patent Application No. 63 / 687,366 filed on August 27, 2024, which is hereby expressly incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The invention generally relates to a unitary impeller, and to a turbomachine including the unitary impeller.2. Description of the Related Art

[0003] Conventional turbomachines include a turbine housing, a bearing housing fixed to the turbine housing, and a compressor housing fixed to the bearing housing such that the bearing housing is disposed between the turbine housing and the compressor housing. Conventional turbomachines also include a turbine wheel disposed in the turbine housing to receive pressurized gas to rotate the turbine wheel, a shaft rotatably fixed to the turbine wheel and extending from the turbine wheel through the bearing housing, and a compressor wheel disposed in the compressor housing and rotatably fixed to the shaft to compress oxidizing agent. Typically, both the composition and pressure of the pressurized gas received by the turbine wheel and the oxidizing agent compressed by the compressor wheel are different. Moreover, the composition, temperature, and pressure of the gases in the bearinghousing are also typically different than those of the pressurized gas received by the turbine wheel and the oxidizing agent compressed by the compressor wheel. As such, conventional turbomachines commonly include a first stand-alone seal disposed about the shaft to fluidly seal the turbine housing and the bearing housing from one another and a second stand-alone seal disposed about the shaft to fluidly seal the compressor housing and the bearing housing from one another.

[0004] Many constructions of the first and second stand-alone seals are known in the art, but all are separate components which increase the amount of components in conventional turbomachines, increase the manufacturing cost of the turbomachine, and increasing the manufacturing time of the turbomachine. Moreover, because the bearing housing is disposed between the turbine housing and the compressor housing, any lubricant present in the bearing housing has the potential to leak past either the first stand-alone seal into the turbine housing or the second stand-alone seal into the compressor housing. Any lubricant which leaks past the second stand-alone seal into the compressor housing contaminates the compressed oxidizing agent. Any lubricant which leaks past the first stand-alone seal into the turbine housing contaminates the exhaust flow as undesirable emissions.

[0005] As such, there remains a need for an improved turbomachine.SUMMARY OF THE INVENTION AND ADVANTAGES

[0006] A turbomachine for receiving pressurized gas and compressing oxidizing agent includes a compressor housing defining a compressor housing interior and a turbine housing coupled to the compressor housing and defining a turbine housing interior. One of the compressor housing and the turbine housing includes a first seal component. The turbomachine also includes a bearing housing coupled to the turbine housing and defining a bearing housing interior. The turbomachine further includes a unitary impeller disposed at leastpartially in the turbine housing interior and at least partially in the compressor housing interior. The unitary impeller is rotatable about an axis and includes a first face having a plurality of turbine blades disposed at least partially in the turbine housing interior and facing in a first direction. The unitary impeller also includes a second face having a plurality of compressor blades disposed at least partially in the compressor housing interior and facing in a second direction opposite the first direction. One of the first face and the second face includes a second seal component configured to cooperate with the first seal component to establish a fluid seal between the compressor housing interior and the turbine housing interior. The turbomachine further includes a shaft rotatable with the unitary impeller and disposed at least partially in the bearing housing interior. The turbomachine further includes an electric machine disposed about the shaft at least partially in the bearing housing interior and configured to convert at least one of rotational motion of the shaft to electrical energy and electrical energy to rotational motion of the shaft.

[0007] Accordingly, the first seal component of either the compressor housing or the turbine housing is able to cooperate with the second seal component of the unitary impeller to establish the fluid seal between the compressor housing interior and the turbine housing interior without the need for a compressor wheel separated from a turbine wheel by a conventional stand-alone sealing arrangement. This arrangement reduces the number of components necessary to establish the fluid seal, reduces the manufacturing cost of the turbomachine, and reduces the manufacturing time of the turbomachine.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0009] FIG. 1 is a perspective view of a turbomachine;

[0010] FIG. 2 is a cross-sectional view of the turbomachine of FIG. 1 taken along axis Al ;

[0011] FIG. 3A is an exploded cross-sectional view of FIG. 2 depicting a first seal component and a second seal component;

[0012] FIG. 3B is an exploded cross-sectional view of another embodiment of the first seal component and the second seal component; and

[0013] FIG. 4 is a perspective view of a unitary impeller for the turbomachine.DETAILED DESCRIPTION OF THE INVENTION

[0014] With reference to the Figures, wherein like numerals indicate like parts throughout the several views, a turbomachine 10 for receiving pressurized gas and compressing oxidizing agent is shown in FIG. 1. The turbomachine 10 includes a compressor housing 12 defining a compressor housing interior 14 and a turbine housing 16 coupled to the compressor housing 12 and defining a turbine housing interior 18. One of the compressor housing 12 and the turbine housing 16 includes a first seal component 20. In other words, either the compressor housing 12 includes the first seal component 20 or the turbine housing 16 includes the first seal component 20. Of course, it is also to be appreciated that, in certain embodiments of the turbomachine 10, both the compressor housing 12 and turbine housing 16 could include portions of the first seal component 20. In such certain embodiments, one of the compressor housing 12 and the turbine 16 includes the first seal component 20. The turbomachine 10 also includes a bearing housing 22 coupled to the turbine housing 16 and defining a bearing housing interior 24.

[0015] The turbomachine 10 further includes a unitary impeller 26 disposed at least partially in the turbine housing interior 18 and at least partially in the compressor housinginterior 14. The unitary impeller 26 is rotatable about an axis Al and includes a first face 28 having a plurality of turbine blades 30 disposed at least partially in the turbine housing interior 18 and facing in a first direction DI. The unitary impeller 26 also includes a second face 32 having a plurality of compressor blades 34 disposed at least partially in the compressor housing interior 14 and facing in a second direction D2 opposite the first direction DI. One of the first face 28 and the second face 32 includes a second seal component 36 configured to cooperate with the first seal component 20 to establish a fluid seal 38 between the compressor housing interior 14 and the turbine housing interior 18. In other words, either the first face 28 includes the second seal component 36 or the second face 32 includes the second seal component 36.

[0016] The turbomachine 10 further includes a shaft 40 rotatable with the unitary impeller 26 and disposed at least partially in the bearing housing interior 24. The turbomachine 10 further includes an electric machine 42 disposed about the shaft 40 at least partially in the bearing housing interior 24 and configured to convert at least one of rotational motion of the shaft 40 to electrical energy and electrical energy to rotational motion of the shaft 40. In other words, the electric machine 42 may be configured to convert rotational motion of the shaft 40 to electrical energy, the electric machine 42 may be configured to convert electrical energy to rotational motion of the shaft 40, or the electric machine 42 may be configured to both convert rotational motion of the shaft 40 to electrical energy and convert electrical energy to rotational motion of the shaft 40.

[0017] Accordingly, the first seal component 20 of either the compressor housing 12 or the turbine housing 16 is able to cooperate with the second seal component 36 of the unitary impeller 26 to establish the fluid seal 38 between the compressor housing interior 14 and the turbine housing interior 18 without the need for a compressor wheel separated from a turbine wheel by a conventional stand-alone sealing arrangement, reducing the number ofcomponents necessary to establish the fluid seal 38, reducing the manufacturing cost of the turbomachine 10, and reducing the manufacturing time of the turbomachine 10.

[0018] Although not required, the turbomachine 10 may be incorporated into a fuel cell system including the turbomachine 10 and a fuel cell. The fuel cell may be of any suitable type. In non-limiting examples, the fuel cell may be a polymer electrolyte membrane fuel cell, a direct methanol fuel cell, an alkaline fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, a solid oxide fuel cell, a fuel cell reformer, a reversible fuel cell, or any combination thereof. The fuel cell may receive a fuel and may receive compressed oxidizing agent from the turbomachine 10. The fuel received by the fuel cell may be hydrogen and / or light hydrocarbons. The fuel cell reacts the fuel and the compressed oxidizing agent to produce a pressurized gas. The pressurized gas is directed from the fuel cell and is received by the turbomachine 10. The pressurized gas may be similar compositionally to the compressed oxidizing agent, but for further including water vapor in the form of humidity. More specifically, the plurality of turbine blades 30 may receive the pressurized gas from the fuel cell. In the embodiments where the pressurized gas is similar compositionally to the compressed oxidizing agent but for further including water vapor in the form of humidity, the plurality of turbine blades 30 may be formed to act as a steam turboexpander.

[0019] In the embodiment where the turbomachine 10 is incorporated into the fuel cell system, the turbomachine 10 limits fuel stack poisoning of the fuel cell. More specifically, the fluid seal 38 established between the compressor housing 12 and the turbine housing 16 by the first seal component 20 and the second seal component 36 limits ingress of lubricant into the compressor housing interior 14. Ingress of lubricant into the compressor housing interior 14 enters the compressed oxidizing agent which poisons the fuel cell.

[0020] Alternatively, it is to be appreciated that the turbomachine 10 may be used in conjunction with an internal combustion engine and the pressurized gas may includecombusted or partially combusted hydrocarbons in the form of exhaust gas. The compressed oxidizing agent may be compressed ambient air, may be compressed oxygen, or may be any combination thereof.

[0021] Although not required, the unitary impeller 26 may have an outer rim 44 extending circumferentially about the axis Al along a radially distal intersection of the first face 28 and the second face 32. The second seal component 36 may be disposed radially between the outer rim 44 and at least one of the plurality of turbine blades 30 and the plurality of compressor blades 34. In other words, the second seal component 36 may be disposed radially between the outer rim 44 and the plurality of turbine blades 30, may be disposed radially between the outer rim 44 and the plurality of compressor blades 34, or may be both radially disposed between the outer rim 44 and the plurality of turbine blades 30 and radially disposed between the outer rim 44 and the plurality of compressor blades 34. It is to be appreciated that the second seal component 36 may even be a part of, or formed partially from, the outer rim 44 while still being disposed radially between the outer rim 44 and the plurality of turbine blades 30 and / or the plurality of compressor blades 34.

[0022] One of the compressor housing 12 and the turbine housing 16 may include a wall 46 radially aligned with the outer rim 44 along the axis A 1 such that the outer rim 44 is radially disposed between the wall 46 and the shaft 40. In other words, the compressor housing 12 may include the wall 46 radially aligned with the outer rim 44 along the axis Al such that the outer rim 44 is radially disposed between the wall 46 and the shaft 40, or the turbine housing 16 may include the wall 46 radially aligned with the outer rim 44 along the axis Al such that the outer rim 44 is radially disposed between the wall 46 and the shaft 40. It is also to be appreciated that, in certain embodiments of the turbomachine 10, both the compressor housing 12 and the turbine housing 16 may cooperate to form the wall 46. In suchcertain embodiments, one of the compressor housing 12 and the turbine 16 includes the wall 46.

[0023] The fluid seal 38 may be further defined as a non-contact seal established such that the first seal component 20 and the second seal component 36 are not in contact with one another to permit the unitary impeller 26 to freely rotate about the axis Al. It is to be appreciated that the non-contact seal includes both non-contact seals where the first seal component 20 and the second seal component 36 are never in contact with one another, and non-contact seals where the first seal component 20 and the second seal component 36 are in contact with one another while the shaft 40 is not rotating but which subsequently lift off from one another once the shaft 40 begins rotating. In a non-limiting example, the fluid seal 38 may be further defined as a labyrinth seal. It is to be appreciated that the labyrinth seal may be a non-contact seal, and may include hybrid labyrinth seals. The first seal component 20 and the second seal component 36 in a hybrid labyrinth seal are in contact with one another while the shaft 40 is not rotating, but subsequently lift off from one another once the shaft 40 begins rotating.

[0024] The fluid seal 38 need not completely seal the turbine housing interior 18 and the compressor housing interior 14 from one another. In other words, the fluid seal 38 limits flow of gases and / or lubricant between the turbine housing interior 18 and the compressor housing interior 14, but the fluid seal 38 need not completely prevent flow of gases and / or lubricant between the turbine housing interior 18 and the compressor housing interior 14.

[0025] The second seal component 36 may face toward the electric machine 42. The second seal component 36 facing toward the electric machine 42 increases the ease of manufacturing the turbomachine 10. More specifically, the second seal component 36 of the unitary impeller 26 may be aligned with the first seal component 20 of the one of thecompressor housing 12 and the turbine housing 16 while the second seal component 36 faces toward the electric machine 42. The other of the compressor housing 12 and the turbine housing 16 may then be disposed about the unitary impeller 26 and coupled to the one of the compressor housing 12 and the turbine housing 16 to enclose the unitary impeller 26 partially in the compressor housing interior 14 and the turbine housing interior 18. The shaft 40 may be rotationally fixed to the unitary impeller 26 before, or after, the unitary impeller 26 is enclosed. The bearing housing 22 may be coupled to the one of the turbine housing 16 and the compressor housing 12 before, or after, the unitary impeller 26 is enclosed.

[0026] In the embodiments where the first face 28 includes the second seal component 36, it is to be appreciated that the second seal component 36 faces in the first direction DI when facing toward the electric machine 42. In the embodiments where the second face 32 includes the second seal component 36, it is to be appreciated that the second seal component 36 faces in the second direction D2 when facing toward the electric machine 42.

[0027] The plurality of turbine blades 30 has an inducer region 48 to receive pressurized gas. The inducer region 48 has a first radius R1 from the axis Al. The plurality of compressor blades 34 has an exducer region 50 to direct compressed oxidizing agent from the plurality of compressor blades 34. The exducer region 50 may have a second radius R2 from the axis Al different from the first radius R 1. Although not required, the second seal component 36 may be at least partially radially disposed between the first radius R1 and the second radius R2. Moreover, the second radius R2 may be greater than the first radius Rl.

[0028] Particularly advantageous are embodiments where the second radius R2 is different than the first radius Rl, the second seal component 36 is at least partially disposed between the first radius Rl and the second radius R2, and the second seal component 36 faces toward the electric machine 42. In these embodiments, the ease of manufacturing the turbomachine 10 is further increased.

[0029] Where the first face 28 includes the second seal component 36 and the second radius R2 is greater than the first radius Rl, the inducer region 48 of the plurality of turbine blades 30 may be disposed at least partially in the turbine housing interior 18 while the second seal component 36 is aligned with the first seal component 20 of the turbine housing 16 and also while the second seal component 36 faces toward the electric machine 42. The compressor housing 12 may then be disposed about the unitary impeller 26 and coupled to the turbine housing 16 to enclose the unitary impeller 26. In this embodiment, the second radius R2 being greater than the first radius Rl allows the first seal component 20 and the second seal component 36 to establish the fluid seal 38 while also preventing the unitary impeller 26 from being inserted too far into the turbine housing interior 18.

[0030] Where the second face 32 includes the second seal component 36 and the first radius Rl is greater than the second radius R2, the exducer region 50 of the plurality of compressor blades 34 may be disposed at least partially in the compressor housing interior 14 while the second seal component 36 is aligned with the first seal component 20 of the compressor housing 12 and also while the second seal component 36 faces toward the electric machine 42. The turbine housing 16 may then be disposed about the unitary impeller 26 and coupled to the compressor housing 12 to enclose the unitary impeller 26. In this embodiment, the first radius Rl being greater than the second radius R2 allows the first seal component 20 and the second seal component 36 to establish the fluid seal 38 while also preventing the unitary impeller 26 from being inserted too far into the compressor housing interior 14.

[0031] Although not required, as shown in FIGS. 3A and 3B, the first seal component 20 may be defined as a groove 52 in one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may be defined as a groove in the compressor housing 12, or the first seal component 20 may be defined as a groove in the turbine housing 16. As also shown in FIGS. 3A and 3B, the second seal component 36 mayinclude a projection 54 extending away from the one of the first face 28 and the second face 32 and disposed at least partially in the groove 52. Said differently, the second seal component 36 may include the projection 54 extending away from the first face 28 and disposed at least partially in the groove 52, or the second seal component 36 may include the projection 54 extending away from the second face 32 and disposed at least partially in the groove 52.

[0032] Although the projection 54 is shown as triangular in cross-section in FIG. 3A and the projection 54 is shown as rectangular in cross-section in FIG. 3B, it is to be appreciated that the projection 54 may be of any shape. Moreover, although the groove 52 is shown as triangular in cross-section in FIG. 3A and the groove 52 is shown as rectangular in cross-section in FIG. 3B, it is also to be appreciated that the groove 52 may be of any shape. Although not required, the shape of the projection 54 may correspond to the shape of the groove 52.

[0033] As further shown in FIGS. 3 A and 3B, the first seal component 20 may further define a second groove 56 in the one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may further define the second groove 56 in the compressor housing 12, or the first seal component 20 may further define the second groove 56 in the turbine housing 16. The second seal component 36 may further include a second projection 58 extending away from the one of the first face 28 and the second face 32 and disposed at least partially in the second groove 56. Said differently, the second seal component 36 may further include the second projection 58 extending away from the first face 28 and disposed at least partially in the second groove 56, or the second seal component 36 may further include the second projection 58 extending away from the second face 32 and disposed at least partially in the second groove 56.

[0034] Although the second projection 58 is shown as triangular in crosssection in FIG. 3A and the second projection 58 is shown as rectangular in cross-section inFIG. 3B, it is to be appreciated that the second projection 58 may be of any shape. Moreover, although the second groove 56 is shown as triangular in cross-section in FIG. 3 A and the second groove 56 is shown as rectangular in cross-section in FIG. 3B, it is also to be appreciated that the second groove 56 may be of any shape. Although not required, the shape of the second projection 58 may correspond to the shape of the second groove 56.

[0035] As further shown in FIG. 3A, the first seal component 20 may further define a third groove 60 in the one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may further define the third groove 60 in the compressor housing 12, or the first seal component 20 may further define the third groove 60 in the turbine housing 16. The second seal component 36 may further include a third projection 62 extending away from the one of the first face 28 and the second face 32 and disposed at least partially in the third groove 60. Said differently, the second seal component 36 may further include the third projection 62 extending away from the first face 28 and disposed at least partially in the third groove 60, or the second seal component 36 may further include the third projection 62 extending away from the second face 32 and disposed at least partially in the third groove 60.

[0036] Although the third projection 62 is shown as triangular in cross-section in FIG. 3A, it is to be appreciated that the third projection 62 may be of any shape. Moreover, although the third groove 60 is shown as triangular in cross-section in FIG. 3A, it is also to be appreciated that the third groove 60 may be of any shape. Although not required, the shape of the third projection 62 may correspond to the shape of the third groove 60.

[0037] Alternatively, the first seal component 20 may include the projection 54 extending away from the one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may include the projection 54 extending away from the compressor housing 12, or the first seal component 20 may include the projection extendingaway from the turbine housing 16. The second seal component 36 may be defined as the groove 52 in the one of the first face 28 and the second face 32. Said differently, the second seal component 36 may be defined as the groove 52 in the first face 28, or the second seal component 36 may be defined as the groove 52 in the second face 32. The projection 54 may be disposed at least partially in the groove 52.

[0038] Moreover, the first seal component 20 may include the second projection 58 extending away from the one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may include the second projection 58 extending away from the compressor housing 12, or the first seal component 20 may include the second projection extending away from the turbine housing 16. The second seal component 36 may be defined as the second groove 56 in the one of the first face 28 and the second face 32. Said differently, the second seal component 36 may be defined as the second groove 56 in the first face 28, or the second seal component 36 may be defined as the second groove 56 in the second face 32. The second projection 58 may be disposed at least partially in the second groove 56.

[0039] Additionally, the first seal component 20 may include the third projection 62 extending away from the one of the compressor housing 12 and the turbine housing 16. In other words, the first seal component 20 may include the third projection 62 extending away from the compressor housing 12, or the first seal component 20 may include the third projection extending away from the turbine housing 16. The second seal component 36 may be defined as the third groove 60 in the one of the first face 28 and the second face 32. Said differently, the second seal component 36 may be defined as the third groove 60 in the first face 28, or the second seal component 36 may be defined as the third groove 60 in the second face 32. The third projection 62 may be disposed at least partially in the third groove 60.

[0040] In one embodiment, the turbine housing 16 includes the first seal component 20, and the first face 28 includes the second seal component 36. In another embodiment, the compressor housing 12 includes the first seal component 20, and the second face 32 includes the second seal component 36.

[0041] The turbomachine 10 may further include a spacer 64 disposed about the shaft 40 in the turbine housing interior 18. The spacer 64 is disposed between the unitary impeller 26 and the electric machine 42. The spacer 64 extends from a first spacer end 66 proximal to the unitary impeller 26 and a second spacer end 66 distal from the unitary impeller 26. The spacer 64 curves from the first spacer end 66 to the second spacer end 66 to redirect flow of pressurized gas radially out of the turbine housing interior 18. The turbine housing 16 may define a turbine housing outlet 70 to discharge pressurized gases from the turbine housing interior 18 after the pressurized gases have rotated the unitary impeller 26. Although not required, the turbine housing outlet 70 may be defined to include a plurality of turbine housing outlet holes 72 spaced circumferentially about the axis Al . The spacer 64 redirects flow of the pressurized gas radially to flow out of the turbine housing outlet 70, particularly the turbine housing outlet holes 72.

[0042] Although not required, the unitary impeller 26 may be cast. The unitary impeller 26 may alternatively be formed from a billet and subsequently machined. It is to be appreciated that the unitary impeller 26 may be formed as one-piece. However, it is also to be appreciated that the unitary impeller 26 may even be formed from two separate components and later joined to become one-piece. In a non-limiting example, the unitary impeller 26 may be formed from a first component including the plurality of compressor blades 34 and a second component including the plurality of turbine blades 30 which have been joined, such as by welding, to become one-piece.

[0043] The second seal component 36 may be integral with the unitary impeller 26, such as formed integrally with the unitary impeller 26 or welded to the unitary impeller 26. However, the second seal component 36 may be a separate component which has been fastened to the unitary impeller 26. The second seal component 36 may be integral with the one of the turbine housing 16 and the compressor housing 12, such as formed integrally with the one of the turbine housing 16 and the compressor housing 12 or welded to the one of the turbine housing 16 and the compressor housing 12. However, the first seal component 20 may be a separate component which has been fastened to the one of the turbine housing 16 and the compressor housing 12.

[0044] The bearing housing 22 may further include a bearing arrangement 74 disposed about the shaft 40 to support rotation of the shaft 40 about the axis Al. Although not required, the bearing arrangement 74 may include a plurality of rolling elements, such as balls, cylinders, or spheres. The plurality of rolling elements may be disposed between inner and outer races, and optionally within a cage disposed about the plurality of rolling elements between the inner and outer races. Alternatively, the bearing arrangement 74 may include a journal bearing and / or a plain bearing. Other bearing arrangements 74 not specifically recited above are contemplated in the subject description. The bearing arrangement 74 may be lubricated by the lubricant.

[0045] As shown in FIGS. 1 and 2, the turbine housing 16 may be disposed between the compressor housing 12 and the bearing housing 22. The turbine housing 16 being disposed between the compressor housing 12 and the bearing housing 22 permits the bearing housing 22 to define a lubricant feed channel extending parallel to the axis Al. In other words, the bearing housing 22 may define an axial lubricant feed channel. The axial lubricant feed channel is a simple, cost-effective solution to providing lubricant to cool and / or lubricate thebearing arrangement 74 and the electric machine 42. The bearing housing 22 may also define a coolant channel to provide coolant to the electric machine 42.

[0046] Any lubricant present in the bearing housing interior 24 has the potential to leak into the turbine housing interior 18. However, in the embodiments where the turbine housing 16 is disposed between the bearing housing 22 and the compressor housing 12, lubricant which leaks from the bearing housing interior 24 into the turbine housing interior 18 is removed from the turbine housing interior 18 through the turbine housing outlet 70 and thus does not enter the compressor housing interior 14 and enter the compressed oxidizing agent. As such, it is to be appreciated that the turbine housing 16 being disposed between the bearing housing 22 and the compressor housing 12 prevents poisoning the fuel cell in the embodiments where the turbomachine 10 is incorporated into the fuel cell system. It is further to be appreciated that the compressor housing 12 may be disposed between the bearing housing 22 and the turbine housing 16.

[0047] The compressor housing 12 includes a compressor volute 76 defining a compressor volute outlet 78 to discharge compressed oxidizing agent. The turbine housing 16 includes a turbine volute 80 defining a turbine volute inlet 82 to receive pressurized gas. Although not required, the compressor volute 76 and the turbine volute 80 may share a common wall 84 to facilitate transfer of heat from the compressed oxidizing agent to the pressurized gas. The compressed oxidizing agent immediately leaving the plurality of compressor blades 34 may be between about 100 degrees Celsius and about 220 degrees Celsius. The pressurized gas received by the turbine housing 16 may be between about 50 degrees Celsius and about 90 degrees Celsius. The common wall 84 shared by the compressor volute 76 and the turbine volute 80 serves to increase the temperature of the pressurized gas received by the turbine housing 16 so that the pressurized gas is at a relatively higher temperature when received by the plurality of turbine blades 30, thus imparting more energy to the plurality of turbine blades30 and the shaft 40 which is available to be converted to electrical energy by the electric machine 42. Thus, the common wall 84 increases the efficiency of the turbomachine 10.

[0048] In another embodiment, as shown in FIG. 4, a unitary impeller 26 for a turbomachine 10 is provided. The unitary impeller 26 is rotatable about an axis Al. The unitary impeller 26 includes a first face 28 having a plurality of turbine blades 30 and facing in a first direction DI. The plurality of turbine blades 30 has an inducer region 48 to receive pressurized gas and having a first radius R1 from the axis Al. The unitary impeller 26 also includes a second face 32 having a plurality of compressor blades 34 and facing in a second direction D2 opposite the first direction DI . The plurality of compressor blades 34 has an exducer region 50 to direct compressed oxidizing agent from the plurality of compressor blades 34 and having a second radius R2 from the axis Al different from the first radius Rl. In other words, the second radius R2 may be greater than the first radius Rl, or the second radius R2 may be less than the first radius Rl. One of the first face 28 and the second face 32 includes a seal component 36 configured to establish a fluid seal with a housing 12, 16 of the turbomachine 10. The seal component 36 is at least partially radially disposed between the first radius Rl and the second radius R2.

[0049] In the embodiment shown in FIG. 4, the seal component 36 may include a first projection 54 extending away from the one of the first face 28 and the second face 32. The first projection 54 extends circumferentially about the axis Al. The seal component 36 may also include a second projection 58 extending away from the one of the first face 28 and the second face 32. The second projection 58 extends circumferentially about the axis Al. Although not required, the seal component 36 may include a third projection 62 extending away from the one of the first face 28 and the second face 32. The third projection 62 extends circumferentially about the axis Al. The second projection 58 may be disposed radially between the first projection 54 and the third projection 62.

[0050] The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.

Claims

CLAIMSWhat is claimed is:

1. A turbomachine for receiving pressurized gas and compressing oxidizing agent, said turbomachine comprising:a compressor housing defining a compressor housing interior;a turbine housing coupled to said compressor housing and defining a turbine housing interior,wherein one of said compressor housing and said turbine housing comprises a first seal component;a bearing housing coupled to said turbine housing and defining a bearing housing interior;a unitary impeller disposed at least partially in said turbine housing interior and at least partially in said compressor housing interior, wherein said unitary impeller is rotatable about an axis and comprises,a first face having a plurality of turbine blades disposed at least partially in said turbine housing interior and facing in a first direction; anda second face having a plurality of compressor blades disposed at least partially in said compressor housing interior and facing in a second direction opposite said first direction,wherein one of said first face and said second face comprises a second seal component configured to cooperate with said first seal component to establish a fluid seal between said compressor housing interior and said turbine housing interior; a shaft rotatable with said unitary impeller and disposed at least partially in said bearing housing interior; andan electric machine disposed about said shaft at least partially in said bearing housing interior and configured to convert at least one of rotational motion of said shaft to electrical energy and electrical energy to rotational motion of said shaft.

2. The turbomachine as set forth in claim 1, wherein said unitary impeller has an outer rim extending circumferentially about said axis along a radially distal intersection of said first face and said second face, and wherein said second seal component is disposed radially between said outer rim and at least one of said plurality of turbine blades and said plurality of compressor blades.

3. The turbomachine as set forth in claim 2, wherein said one of said compressor housing and said turbine housing includes a wall radially aligned with said outer rim along said axis such that said outer rim is radially disposed between said wall and said shaft.

4. The turbomachine as set forth in any of the preceding claims, wherein said fluid seal is further defined as a non-contact seal established such that said first seal component and said second seal component are not in contact with one another to permit said unitary impeller to freely rotate about said axis.

5. The turbomachine as set forth in any of the preceding claims, wherein said fluid seal is further defined as a labyrinth seal.

6. The turbomachine as set forth in any of the preceding claims, wherein said second seal component faces toward said electric machine.

7. The turbomachine as set forth in any of the preceding claims, wherein said plurality of turbine blades has an inducer region to receive pressurized gas and having a first radius from said axis, wherein said plurality of compressor blades has an exducer region to direct compressed oxidizing agent from said plurality of compressor blades and having a second radius from said axis different from said first radius, and wherein said second sealcomponent is at least partially radially disposed between said first radius and said second radius.

8. The turbomachine as set forth in claim 7, wherein said second radius is greater than said first radius.

9. The turbomachine as set forth in any of the preceding claims, wherein said first seal component is defined as a groove in said one of said compressor housing and said turbine housing, and wherein said second seal component comprises a projection extending away from said one of said first face and said second face and disposed at least partially in said groove.

10. The turbomachine as set forth in claim 9, wherein said first seal component further defines a second groove in said one of said compressor housing and said turbine housing, and wherein said second seal component further comprises a second projection extending away from said one of said first face and said second face and disposed at least partially in said second groove.

11. The turbomachine as set forth in claim 10, wherein said first seal component further defines a third groove in said one of said compressor housing and said turbine housing, and wherein said second seal component further comprises a third projection extending away from said one of said first face and said second face and disposed at least partially in said third groove.

12. The turbomachine as set forth in any of the preceding claims, wherein said turbine housing comprises said first seal component, and wherein said first face comprises said second seal component.

13. The turbomachine as set forth in claim 1, wherein said compressor housing comprises said first seal component, and wherein said second face comprises said second seal component.

14. The turbomachine as set forth in any of the preceding claims further comprising a spacer disposed about said shaft in said turbine housing interior and disposed between said unitary impeller and said electric machine, wherein said spacer extends from a first spacer end proximal to said unitary impeller and a second spacer end distal from said unitary impeller, and wherein said spacer curves from said first spacer end to said second spacer end to redirect flow of pressurized gas radially out of said turbine housing interior.

15. The turbomachine as set forth in any of the preceding claims, wherein said unitary impeller is cast.

16. The turbomachine as set forth in claim 1, wherein said unitary impeller is formed from a billet and subsequently machined.

17. The turbomachine as set forth in any of the preceding claims, wherein said turbine housing is disposed between said compressor housing and said bearing housing.

18. The turbomachine as set forth in any of the preceding claims, wherein said compressor housing comprises a compressor volute defining a compressor volute outlet to discharge compressed oxidizing agent and said turbine housing comprises a turbine volute defining a turbine volute inlet to receive pressurized gas, and wherein said compressor volute and said turbine volute share a common wall to facilitate transfer of heat from the compressed oxidizing agent to the pressurized gas.

19. A unitary impeller for a turbomachine and rotatable about an axis, said unitary impeller comprising:a first face having a plurality of turbine blades and facing in a first direction, wherein said plurality of turbine blades has an inducer region to receive pressurized gas and having a first radius from said axis; anda second face having a plurality of compressor blades and facing in a second direction opposite said first direction, wherein said plurality of compressor blades has an exducer regionto direct compressed oxidizing agent from said plurality of compressor blades and having a second radius from said axis different from said first radius;wherein one of said first face and said second face comprises a seal component configured to establish a fluid seal with a housing of the turbomachine; andwherein said seal component is least partially radially disposed between said first radius and said second radius.

20. The unitary impeller as set forth in claim 19, wherein said seal component comprises a first projection extending away from said one of said first face and said second face and circumferentially about said axis, and wherein the seal component comprises a second projection extending away from said one of said first face and said second face and circumferentially about said axis.

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