centrifugal compressor

Abstract

The centrifugal compressor C1 comprises a compressor impeller 9, a diffuser flow path 11 located outside the compressor impeller 9 in a radial direction and into which fluid flows from the compressor impeller 9, a plurality of vanes 50 provided in the diffuser flow path 11 and arranged along a circumferential direction, a first surface 43 defining the diffuser flow path 11, and a second surface 25 defining the diffuser flow path 11 and facing the first surface 43 across the vanes 50, wherein a distance CL1 is formed between each of the plurality of vanes 50 and at least one of the first surface 43 and the second surface 25, the distance extending radially outward from the guide edge LE of the vane 50 and being closed or narrowed at a position between the guide edge LE and a follower edge TE.

Description

Technical field

[0001] The present disclosure relates to a centrifugal compressor. The present application claims priority based on Japanese patent application No. 2023-47895, filed on March 24, 2023, the contents of which are incorporated herein by reference. State of the art

[0002] A centrifugal compressor can comprise a plurality of vanes in a diffuser flow path. For example, patent literature 1 discloses a centrifugal compressor comprising a diffuser with a plurality of partition walls. Each partition wall is divided into a fixed wall on a radially outer side and a thermally actuated wall on a radially inner side. A small gap is formed between the fixed wall and the thermally actuated wall. The fixed wall is fixed at both ends to a diffuser surface. A radially outer half of the thermally actuated wall is fixed at both ends to the diffuser surface, while a radially inner half has a gap between its ends and the diffuser surface. Accordingly, the radially inner half of the thermally actuated wall is deformable. The thermally actuated wall comprises two metal plates.A plate with a low coefficient of thermal expansion is located at the rear, and a plate with a high coefficient of thermal expansion is located at the front. According to this design, the thermally actuated wall is configured such that the gap between the two thermally actuated walls is widened when the gas flowing into the diffuser is at a low temperature (low-speed rotation state) and narrowed when the gas is at a high temperature (high-speed rotation state), due to the difference in the coefficients of thermal expansion of the two metal plates. Thus, the amount of gas flowing into the diffuser can be controlled according to the rotation state of the centrifugal compressor. Citation list for patent literature

[0003] Patent Literature 1: JP H10-9196 A Brief description of the technical problem

[0004] When a centrifugal compressor incorporates a multitude of blades in a diffuser flow path, a phenomenon known as "rotor-stator interaction" can occur. In a centrifugal compressor, it is desirable to reduce the excitation force caused by this phenomenon.

[0005] The present disclosure aims to provide a centrifugal compressor that can reduce excitation force. Solution to the problem

[0006] To solve the above problem, a centrifugal compressor according to one aspect of the present disclosure comprises a compressor impeller, a diffuser flow path located outside the compressor impeller in a radial direction and into which a fluid flows from the compressor impeller, a plurality of vanes provided in the diffuser flow path and arranged along a circumferential direction, a first surface defining the diffuser flow path, a second surface defining the diffuser flow path and facing the first surface across the vanes, wherein a gap is formed between each of the plurality of vanes and at least one of the first surface and the second surface, the gap extending radially outward from a leading edge of the vane and being closed or narrowed at a position between the leading edge and a following edge.

[0007] The gap can be formed between each wing and one of the first surface and the second surface, and the guiding edge can be in contact with the other of the first surface and the second surface.

[0008] The centrifugal compressor can include a collar facing the blade surfaces of the compressor impeller and connected to the first surface, and a gap can be formed between each blade and the first surface, and the guide edge can be in contact with the second surface.

[0009] The distance can decrease continuously when moving radially outwards from the guide edge to the position between the guide edge and the follower edge.

[0010] The height of the wing in one axial direction can be lower at this distance than at other positions.

[0011] At least one of the first surface and the second surface can include an area that defines the distance and intersects the radial direction.

[0012] In a design where at least one of the first surface and the second surface encompasses the area that defines the distance and intersects the radial direction, both end surfaces of the wing can be parallel to the radial direction in the axial direction, and the wing can be rotatable about a central axis that is parallel to an axial direction.

[0013] In a design where the wing is rotatable, the gap can disappear in a position where the throat width between two adjacent wings is narrowest out of a multitude of wings. Advantageous effects of the invention

[0014] According to the present invention, an excitation force can be reduced. Brief description of drawings Fig. Figure 1 is a schematic cross-sectional view of a turbocharger comprising a centrifugal compressor according to a first embodiment. Fig. Figure 2 is a schematic enlarged cross-sectional view of part A in Fig. 1. Fig. Figure 3 shows results of analyses of an excitation force. Fig. Figure 4 is a schematic enlarged cross-sectional view of a centrifugal compressor according to a second embodiment. Fig. Figure 5 is a schematic enlarged cross-sectional view of a centrifugal compressor according to a third embodiment. Fig. Figure 6 is a schematic enlarged cross-sectional view of a centrifugal compressor according to a fourth embodiment. Fig. Figure 7 is a schematic enlarged cross-sectional view of a centrifugal compressor according to a fifth embodiment. Fig. Figure 8 is a schematic enlarged cross-sectional view of a centrifugal compressor according to a sixth embodiment. Description of embodiments

[0015] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0016] Specific dimensions, materials, and numerical values ​​described in the embodiments are merely examples for better understanding and do not limit the present disclosure unless otherwise stated. In this specification and in the drawings, duplicate explanations for components that have essentially the same functions and designs have been avoided by assigning the same symbol. Furthermore, components not directly related to the present disclosure have been omitted from the figures.

[0017] Fig. Figure 1 is a schematic cross-sectional view of a turbocharger TC comprising a centrifugal compressor C1 according to a first embodiment. For example, the turbocharger TC is used in a power engine. The turbocharger TC comprises a housing 1, a shaft 7, a turbine impeller 8, and a compressor impeller 9.

[0018] As will be described later, the turbine impeller 8 and the compressor impeller 9 are arranged concentrically with the shaft 7 and rotate integrally with the shaft 7. Accordingly, in the present disclosure, the axial directions, radial directions, and circumferential directions of the shaft 7, the turbine impeller 8, and the compressor impeller 9 can simply be referred to as an "axial direction," a "radial direction," and a "circumferential direction," respectively, unless otherwise specified. Furthermore, in the present disclosure, the central axes of the shaft 7, the turbine impeller 8, and the compressor impeller 9 can simply be referred to as a "central axis," unless otherwise specified.

[0019] The housing 1 comprises a bearing housing 2, a turbine housing 3, and a compressor housing 4. In the axial direction, one end of the bearing housing 2 is connected to the turbine housing 3 by a fastener 21a, such as a bolt. In the axial direction, the other end of the bearing housing 2 is connected to the compressor housing 4 by a fastener 21b, such as a bolt.

[0020] The bearing housing 2 includes a bearing bore 22. The bearing bore 22 extends axially within the bearing housing 2. The bearing bore 22 accommodates bearings 23 and 24. The bearings 23 and 24 rotatably support the shaft 7.

[0021] The turbine impeller 8 is located at one end of the shaft 7 in the axial direction. The turbine impeller 8 is rotatably mounted in the turbine housing 3. The compressor impeller 9 is located at a second end of the shaft 7, which is axially opposite to the first end. The compressor impeller 9 is rotatably mounted in the compressor housing 4. The shaft 7, the turbine impeller 8, and the compressor impeller 9 rotate together as a single unit.

[0022] The compressor housing 4 includes an intake opening 10 at one end, which is axially opposite to the bearing housing 2. The intake opening 10 is connected to an air filter (not shown). The bearing housing 2 and the compressor housing 4 define a diffuser flow path 11 between them. The diffuser flow path 11 is annular in shape. The diffuser flow path 11 lies radially outside the compressor impeller 9. The diffuser flow path 11 is connected to the intake opening 10 by means of the compressor impeller 9. The diffuser flow path 11 contains a plurality of vanes 50 (described in detail below).

[0023] The compressor housing 4 includes a compressor screw flow path 12. The compressor screw flow path 12 lies outside the diffuser flow path 11 in the radial direction. The compressor screw flow path 12 is connected to the diffuser flow path 11. Furthermore, the compressor screw flow path 12 is connected to an intake port of a power unit (not shown).

[0024] The compressor housing 4 includes a collar 41. The collar 41 lies outside the compressor impeller 9 in the radial direction and faces the blade surfaces of the compressor impeller 9 in both the radial and axial directions. A gap is formed between the collar 41 and the blades of the compressor impeller 9. The collar 41 has the shape of a curved surface that extends radially outwards when moving away from the intake opening 10 in the axial direction.

[0025] In the present embodiment, a portion of the compressor housing 4 is designed as an annular piece 42. For example, the annular piece 42 comprises at least one surface facing the vanes 50 in the axial direction of the compressor housing 4. Specifically, the annular piece 42 comprises a first surface 43. The first surface 43 defines the diffuser flow path 11. The first surface 43 is connected to the collar 41. In the present embodiment, the remaining portion of the compressor housing 4 is designed as a main body 44. The annular piece 42 is fixed to the main body 44. In the present embodiment, the annular piece 42 is fitted into the main body 44. In another embodiment, the annular piece 42 can be fixed to the main body 44 by other means, such as a bolt.

[0026] In the centrifugal compressor C1, when the compressor impeller 9 rotates, a fluid (e.g., air) is drawn from the intake opening 10 into the compressor housing 4. The fluid is accelerated as it passes through the compressor impeller 9. The fluid is pressurized in the diffuser flow path 11 and the compressor screw flow path 12. The pressurized fluid flows out of an outlet (not shown) and is directed to the intake port of the engine.

[0027] The turbine housing 3 includes an exhaust port 13 at one end, which is axially opposite to the bearing housing 2. The exhaust port 13 is connected to an exhaust gas cleaner (not shown). The turbine housing 3 includes a flow path 14. The flow path 14 is annular in shape. The flow path 14 lies outside the turbine impeller 8 in the radial direction. The flow path 14 is connected to the exhaust port 13 by means of the turbine impeller 8.

[0028] The turbine housing 3 includes a turbine screw flow path 15. The turbine screw flow path 15 lies outside the flow path 14 in the radial direction. The turbine screw flow path 15 is connected to the flow path 14. Furthermore, the turbine screw flow path 15 is connected to a gas inlet (not shown). The gas inlet receives exhaust gas that is discharged from an exhaust manifold (not shown) of the engine.

[0029] In the turbine housing 3, the exhaust gas is guided from the gas inlet to the turbine screw flow path 15 and is further guided to the discharge opening 13 by means of the flow path 14 and the turbine runner 8. The exhaust gas rotates the turbine runner 8 as it passes through it.

[0030] The rotational force of the turbine impeller 8 is transmitted to the compressor impeller 9 via the shaft 7. When the compressor impeller 9 rotates, the fluid is pressurized as described above. The pressurized fluid is then directed to the intake port of the engine.

[0031] Next, the diffuser flow path 11 and the wings 50 will be described in detail.

[0032] Fig. Figure 2 is a schematic enlarged cross-sectional view of part A in Fig. 1. In Fig. Figure 2 shows only one vane 50, but other vanes 50 are designed in the same way. As described above, the annular portion 42 of the compressor housing 4 comprises the first surface 43. The bearing housing 2 comprises a second surface 25, which faces the first surface 43 in the axial direction. The diffuser flow path 11 is defined by the first surface 43 and the second surface 25. In this disclosure, "define" can refer to determining a subdivision or boundary of a space, such as a flow path or a distance. In the present embodiment, the second surface 25 has a planar shape that is parallel to the radial direction and extends radially from an inside to an outside with respect to a guide edge LE of the vane 50.

[0033] The vane 50 is arranged radially outside the compressor impeller 9. The plurality of vanes 50 are arranged circumferentially. In the present embodiment, the end faces 51 and 52 of the vane 50 are parallel to the radial direction in the axial direction. In the present embodiment, the end face 51 of the vane 50 is fixed to the second surface 25. Accordingly, the guide edge LE of the vane 50 is in contact with the second surface 25. Each vane 50 is formed from the same material, such as an aluminum alloy or another metal. Each vane 50 is monolithic from the guide edge LE to a subsequent edge TE.

[0034] In the present embodiment, an axial distance CL1 is formed between the end surface 52 of each wing 50 and the first surface 43. The distance CL1 extends radially outward from the guide edge LE of each wing 50 and narrows between the guide edge LE and the follower edge TE. Specifically, the distance CL1 extends radially outward from the guide edge LE to the follower edge TE, while continuously decreasing as one moves away from the guide edge LE to a position P1 between the guide edge LE and the follower edge TE.

[0035] More specifically, in the present embodiment, the first surface 43 comprises, in a region radially inside position P1, a curved surface 43a connected to the collar 41 and inclined with respect to the radial direction, and, in a region radially outside position P1, a flat surface 43b parallel to the radial direction. In other words, position P1 can also be described as a boundary between the radially inner curved surface 43a and the radially outer flat surface 43b at the first surface 43. The distance CL1 decreases continuously with radial outward movement in a region where the end surface 52 of the wing 50 faces the curved surface 43a, and is constant in a region where the end surface 52 faces the flat surface 43b.

[0036] For example, dimensions such as the width of the gap CL1 in the axial direction and the distance from the guide edge LE to the position P1 in the radial direction can be determined taking into account factors such as the excitation force of the centrifugal compressor C1 and the efficiency of the centrifugal compressor C1.

[0037] Fig. Figure 3 shows results from analyses of an excitation force. Fluid analyses (CFD: Computational Fluid Dynamics) were performed using models similar to the centrifugal compressor C1 as described in Figure 3. Fig. 1 and Fig. Figure 2 shows that three models were used in the analyses. The first model includes no gap between each wing 50 and the first surface 43, and between each wing 50 and the second surface 25 (no gap). The second model includes a gap between each wing 50 and the first surface 43 (with a gap on one side of the first surface). The third model includes a gap between each wing 50 and the second surface 25 (with a gap on one side of the second surface). It should be noted that in these analyses, the gaps in the second and third models extend from the leading edge LE to the following edge TE with a constant width.

[0038] A vertical axis indicates a maximum static pressure component around the vane 50, which corresponds to the excitation force. It is known that a vane diffuser exhibits a greater excitation force, due to a phenomenon called "rotor-stator interaction," for a vibration mode having a mode order equal to the number of vanes 50. Accordingly, it shows Fig. 3 Results of analyses for a vibration mode that has a mode order equal to the number of wings 50.

[0039] As from Fig. As can be understood from paragraph 3, the excitation force is reduced by creating a gap on the side of the first surface or on the side of the second surface. However, such a gap also reduces the efficiency of the centrifugal compressor C1. In the present embodiment, the excitation force can be reduced by creating the gap CL1 between the vanes 50 and the first surface 43, and a reduction in efficiency can be limited by narrowing the width of the gap CL1 at position P1 between the guide edge LE and the follower edge TE.

[0040] The centrifugal compressor C1, as described above, comprises the compressor impeller 9, the diffuser flow path 11, which lies outside the compressor impeller 9 in the radial direction and into which the fluid flows from the compressor impeller 9, the plurality of vanes 50 provided in the diffuser flow path 11 and arranged along the circumferential direction, the first surface 43, which defines the diffuser flow path 11, and the second surface 44, which defines the diffuser flow path 11 and faces the first surface 43 across the vanes 50. The gap CL1, which extends radially outward from the leading edge LE of the vane 50 and is narrowed at position P1 between the leading edge LE and the following edge TE, is formed between each vane 50 and the first surface 43.According to such a design, the excitation force can be reduced by forming the distance CL1 between the wing 50 and the first surface 43, and a reduction in efficiency can be limited by narrowing the width of the distance CL1 at position P1.

[0041] Furthermore, in the centrifugal compressor C1, a distance CL1 is formed between each vane 50 and one of the first surfaces 43 and the second surface 25 (between each vane 50 and the first surface 43 in the present embodiment), and the guide edge LE is in contact with the other of the first surface 43 and the second surface 25 (the second surface 25 in the present embodiment). According to this design, one end of the guide edge LE contacts either the first surface 43 or the second surface 25. Accordingly, an increase in the excitation force due to this contact can be limited.

[0042] Furthermore, the centrifugal compressor C1 includes the collar 41, which faces the blade surfaces of the compressor impeller 9 and is connected to the first surface 43, wherein the distance CL1 is formed between each blade 50 and the first surface 43, and the guide edge LE is in contact with the second surface 25. According to such a design, the distance CL1 is defined by the first surface 43, which is connected to the collar 41, and therefore the distance CL1 can be formed as an extension of the collar 41. Thus, for example, the distance CL1 can be formed by redesigning an existing centrifugal compressor C1.

[0043] Furthermore, in the centrifugal compressor C1, the distance CL1 decreases continuously as it moves radially outward from the guide edge LE to position P1 between the guide edge LE and the follower edge TE. This design prevents sudden changes in flow.

[0044] Furthermore, in the centrifugal compressors C1, at least one of the first surface 43 and the second surface 25 (the first surface 43 in the present embodiment) comprises the curved surface 43a, which defines the distance CL1 and intersects the radial direction. According to such a design, a sudden change in flow can be avoided.

[0045] Other embodiments will be described next.

[0046] Fig. Figure 4 is a schematic enlarged cross-sectional view of a centrifugal compressor C2 according to a second embodiment. The centrifugal compressor C2 differs from the centrifugal compressor C1 according to the first embodiment in that a gap CL2 is formed between each vane 50 and the second surface 25. With respect to other configurations, the centrifugal compressor C2 can be the same as the centrifugal compressor C1.

[0047] In the present embodiment, the first surface 43 comprises the curved surface 43a in a region radially inside the guide edge LE and comprises the flat surface 43b in a region radially outside the guide edge LE, instead of position P1 (not shown in Fig. 4) In the present embodiment, the end surface 52 of the wing 50 is fixed to the flat surface 43b of the first surface 43. Accordingly, the guide edge LE of the wing 50 is in contact with the first surface 43.

[0048] In the present embodiment, the second surface 25 comprises, in a region radially inside a position P2 between the guide edge LE and the follower edge TE, a curved surface 25a inclined with respect to the radial direction for approaching the wing 50 when approaching position P2, and, in a region radially outside position P2, a flat surface 25b parallel to the radial direction. In other words, position P2 can also be described as a boundary between the radially inner curved surface 25a and the radially outer flat surface 25b of the second surface 25.

[0049] In the present embodiment, an axial distance CL2 is formed between each wing 50 and the second surface 25. In this embodiment, the distance CL2 extends from the guide edge LE to the follower edge TE, while it decreases continuously when moving radially outward from the guide edge LE to position P2. More specifically, the distance CL2 decreases continuously when moving radially outward in a region where the end surface 51 of the wing 50 faces the curved surface 25a, and is constant in a region where the end surface 51 faces the flat surface 25b.

[0050] Such a centrifugal compressor C2 can have essentially the same effects as the centrifugal compressor C1.

[0051] Fig. Figure 5 is a schematic enlarged cross-sectional view of a centrifugal compressor C3 according to a third embodiment. The centrifugal compressor C3 differs from the centrifugal compressor C2 according to the second embodiment in that the vanes 50 are also fixed to the second surface 25. With respect to other configurations, the centrifugal compressor C3 can be the same as the centrifugal compressor C2.

[0052] In the present embodiment, a portion of the bearing housing 2 is designed as an annular piece 26. For example, the annular piece 26 can comprise at least the curved surface 25a. In the present embodiment, the remaining portion of the bearing housing 2 is designed as a main body 27. The annular piece 26 is fixed to the main body 27. In the present embodiment, the annular piece 26 is fitted into the main body 27. In another embodiment, the annular piece 26 can be fixed to the main body 27 by other means, such as a bolt.

[0053] In the present embodiment, the wings 50 are fixed to the second surface 25, more specifically to the flat surface 25b, in a region that is radially outside position P2. Accordingly, in the present embodiment, the wings 50 are fixed on both sides of the axial direction.

[0054] In the present embodiment, the distance CL3 extends radially outwards from the guide edge LE and is closed at position P2 between the guide edge LE and the follower edge TE.

[0055] Such a centrifugal compressor C3 can have essentially the same effects as centrifugal compressors C1 and C2. In particular, in the present embodiment, the gap CL3 at position P2 between the guide edge LE and the follower edge TE is closed. Thus, the excitation force can be reduced, while a reduction in efficiency is further limited.

[0056] Fig. Figure 6 is a schematic enlarged cross-sectional view of a centrifugal compressor C4 according to a fourth embodiment. The centrifugal compressor C4 differs from the centrifugal compressor C3 according to the third embodiment in that the distance CL1 is also formed between each vane 50 and the first surface 43. With respect to other configurations, the centrifugal compressor C4 can be the same as the centrifugal compressor C3.

[0057] The first surface 43 and the distance CL1 between each vane 50 and the first surface 43 can be designed in the same way as in the first embodiment. Accordingly, it can be said that the centrifugal compressor C4 is a combination of the centrifugal compressor C1 according to the first embodiment and the centrifugal compressor C3 according to the third embodiment.

[0058] Such a centrifugal compressor C4 can have essentially the same effects as centrifugal compressors C1, C2, and C3. In particular, in the present embodiment, the centrifugal compressor C4 comprises the distance CL1 between each vane 50 and the first surface 43, and the distance CL3 between each vane 50 and the second surface 25. Thus, the excitation force can be further reduced.

[0059] Fig. Figure 7 is a schematic cross-sectional view of a centrifugal compressor C5 according to a fifth embodiment. Fig. 7 corresponds to a section of the cross-sectional view, which runs along a line VII-VII in Fig. Figure 1 is obtained and shows a portion of the plurality of vanes 50 as viewed in the axial direction. The centrifugal compressor C5 differs from the centrifugal compressor C1 according to the first embodiment in that each vane 50 is rotatable about a central axis Ax that is parallel to the axial direction. With respect to other configurations, the centrifugal compressor C5 can be the same as the centrifugal compressor C1.

[0060] The top view of Fig. Figure 7 shows the wings 50 in a first position, where the throat width between adjacent wings 50 is at its widest. The lower view of Fig. Figure 7 shows the wings 50 in a second position, where the groove width is narrowest. As described above, in the present embodiment each wing 50 is rotatable about the central axis Ax. Accordingly, in the present embodiment, the “position P1 between the guide edge LE and the follower edge TE” can be defined as a position between the guide edge LE and the follower edge TE for the wing 50 in the first position. Furthermore, as described above, position P1 is also defined as the boundary between the radially inner curved surface 43a and the radially outer flat surface 43b for the first surface 43. Fig. Position P1 is indicated by a dashed line.

[0061] As seen in the top view of Fig. Figure 7 shows that when the vanes 50 are arranged in the first position, the guide edge LE is radially inside position P1. Accordingly, a portion of the end surface 52 of the vane 50 faces the curved surface 43a. In the present embodiment, as described above, the end surface 52 of the vane 50 is axially parallel to the radial direction. Thus, a distance CL4 is formed between the end surface 52 of the vane 50 and the curved surface 43a, as in the centrifugal compressor C1 of the first embodiment.

[0062] As the wing 50 rotates from the first position to the second position, the area facing the curved surface 43a at the end surface 52 of the wing 50 decreases. Accordingly, the distance CL4 decreases.

[0063] As in the lower figure of Fig. As shown in Figure 7, when the wing 50 is in the second position, the guide edge LE lies radially outside position P1. Accordingly, the end surface 52 of the wing 50 does not face the curved surface 43a, but rather the flat surface 43b. Since the wing 50 and the flat surface 43b are parallel to each other, the gap CL4, which is closed or narrowed between the guide edge LE and the follower edge TE, no longer exists between the wing 50 and the flat surface 43b. Note that a small constant gap may exist along the radial direction between the wing 50 and the flat surface 43b to allow rotation of the wing 50.

[0064] Such a centrifugal compressor C5 can have essentially the same effects as centrifugal compressor C1. In particular, in the present embodiment, the two end faces 51 and 52 of the impeller 50 are axially parallel to the radial direction, and the impeller 50 is rotatable about the central axis Ax, which is parallel to the axial direction. According to such a design, the distance CL4 decreases as the impeller 50 rotates from the first position to the second position. For example, when the centrifugal compressor C5 operates at a low rotational speed, the excitation force is not a problem. Accordingly, no distance between the impeller 50 and the flat surface 43b is required for operation at a low rotational speed. Thus, when the centrifugal compressor C5 operates at a low rotational speed, a reduction in efficiency can be limited by decreasing the distance CL4.

[0065] Furthermore, in the C5 centrifugal compressor, the gap CL4 disappears in the second position, where the throat width is narrowest. According to such a design, any reduction in efficiency can be further limited.

[0066] Fig. Figure 8 is a schematic enlarged cross-sectional view of a centrifugal compressor C6 according to a sixth embodiment. The centrifugal compressor C6 differs from the centrifugal compressor C1 according to the first embodiment in that the end surface 52 of each vane 50 comprises a curved surface 52a inclined with respect to the radial direction, and a portion facing the vanes 50, in the first surface 43, is a flat surface. With respect to other configurations, the centrifugal compressor C6 can be the same as the centrifugal compressor C1.

[0067] In the present embodiment, the first surface 43 comprises the curved surface 43a in a region radially inside the guide edge LE, and comprises the flat surface 43b in a region radially outside the guide edge LE, instead of the aforementioned position P1 (not in Fig. 8 shown). In the present embodiment, the wing 50 is fixed both to the flat surface 43b of the first surface 43 and to the second surface 25.

[0068] The end surface 52 of the wing 50 comprises the curved surface 52a, which is radially inside position P3 between the leading edge LE and the following edge TE, and a flat surface 52b, which is radially outside position P3. The curved surface 52a extends radially outward from the leading edge LE to position P3 while being inclined with respect to the radial direction. In other words, the height changes in the axial direction from the end surface 51 to the end surface 52 of the wing 50 from the leading edge LE to position P3. Specifically, the height in the axial direction of the wing 50 increases as it moves away from the leading edge LE in the direction of position P3. The flat surface 52b extends parallel with respect to the radial direction from position P3 to the following edge TE. An axial distance CL5 is formed between the curved surface 52a of the wing 50 and the flat surface 43b of the first surface 43.In other words, the height in the axial direction of the wing 50 is lower at the axial distance CL5 than at other positions.

[0069] Such a centrifugal compressor C6 can have essentially the same effect as that of the centrifugal compressor C1. In particular, in the present embodiment, the height in the axial direction of the vane 50 is lower at the distance CL5 than at other positions. According to such a design, a sudden change in flow can be prevented.

[0070] Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, the present disclosure is not limited thereto. It is obvious that a person skilled in the art can conceive of numerous examples of variations or modifications within the scope of the claims, which shall also be understood as belonging to the technical scope of the present disclosure.

[0071] For example, in the centrifugal compressor C1 of the first embodiment, the Fig. Referring to section 2, the distance CL1 is continuous when moving radially outward from the guide edge LE to position P1. In another embodiment, for example, the distance CL1 from the guide edge LE to position P1 can be constant and can be narrowed at position P1 in the manner of a step. In other words, the distance CL1 can have a right-angled shape from the guide edge LE to position P1 when viewed in a cross-section along the axial direction. The same applies to the other distances CL2, CL3, and CL5.

[0072] Furthermore, the centrifugal compressor C5, shown in the lower figure in Fig. Referring to section 7, the guide edge LE of the wing 50 is radially outside position P1 in the second position, where the groove width is narrowest. In other embodiments, the guide edge LE may lie radially inside position P1 in the second position, where the groove width is narrowest. In other words, the distance CL4 need not disappear in the second position.

[0073] Furthermore, the C6 centrifugal compressor includes, on Fig. Referring to section 8, the end surface 52, which faces the first surface 43, in the case of the wing 50, is the curved surface 52a, which defines the distance CL5. Alternatively or additionally, in another embodiment, the end surface 51, which faces the second surface 25, may comprise a similar area. Reference symbol list 1 case 9 Compressor impeller 11 Diffuser flow path 25 second area 25a curved surface (area that intersects the radial direction, in the second surface) 41 collars 43 first area 43a curved surface (area that intersects the radial direction in the first surface) 50 wings 51 End surface of the wing 52 End surface of the wing 52a curved surface (area that intersects the radial direction where the wing is) Axis central axis of the wing C1 centrifugal compressor C2 centrifugal compressor C3 centrifugal compressor C4 centrifugal compressor C5 centrifugal compressor C6 centrifugal compressor CL1 distance CL2 distance CL3 distance CL4 distance CL5 distance LE guide edge P1 Position between the leading edge and the following edge P2 Position between the leading edge and the following edge P3 Position between the leading edge and the following edge TE Follow-up edge QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-47895

[0001] JP H10-9196 A

[0003]

Claims

[1] Centrifugal compressor, which features: a compressor impeller; a diffuser flow path that lies outside the compressor impeller in a radial direction and into which the fluid flows from the compressor impeller; a multitude of wings that are provided in the diffuser flow path and are arranged along a circumferential direction; a first surface that defines the diffuser flow path; and a second surface that defines the diffuser flow path and faces the first surface across the wings, wherein a gap is formed between each of the plurality of wings and at least one of the first surface and the second surface, wherein the gap extends radially outwards from a guide edge of the wing and is closed or narrowed at a position between the guide edge and a follower edge. [2] Centrifugal compressor according to claim 1, wherein the distance between each vane and one of the first surface and the second surface is formed and the guide edge is in contact with the other of the first surface and the second surface. [3] Centrifugal compressor according to claim 2, comprising: a collar facing the blade surfaces of the compressor impeller and connected to the first surface, wherein the distance between each wing and the first surface is formed and the guiding edge is in contact with the second surface. [4] Centrifugal compressor according to any one of claims 1 to 3, wherein the distance continuously decreases when moving radially outwards from the guide edge to the position between the guide edge and the follower edge. [5] Centrifugal compressor according to any one of claims 1 to 3, wherein the height of the vane in an axial direction is lower at the distance than at other positions. [6] Centrifugal compressor according to claim 4, wherein an end face of the vane in an axial direction comprises a region which defines the distance and which intersects the radial direction. [7] Centrifugal compressor according to any one of claims 1 to 3, wherein the at least one of the first surface and the second surface comprises a region that defines the distance and intersects the radial direction. [8] Centrifugal compressor according to claim 4, wherein at least one of the first surface and the second surface comprises a region that defines the distance and intersects the radial direction. [9] Centrifugal compressor according to claim 5, wherein at least one of the first surface and the second surface comprises a region that defines the distance and intersects the radial direction. [10] Centrifugal compressor according to claim 6, wherein at least one of the first surface and the second surface comprises a region that defines the distance and intersects the radial direction. [11] Centrifugal compressor according to claim 7, wherein Both end surfaces of the wing are parallel to the radial direction in an axial direction, and the wing is rotatable about a central axis that is parallel to the axial direction. [12] Centrifugal compressor according to claim 8, wherein Both end surfaces of the wing are parallel to the radial direction in an axial direction, and the wing is rotatable about a central axis that is parallel to the axial direction. [13] Centrifugal compressor according to claim 11, wherein the distance vanishes in a position where a throat width between two adjacent wings from the plurality of wings is narrowest. [14] Centrifugal compressor according to claim 12, wherein the distance vanishes in a position where a throat width between two adjacent wings from the plurality of wings is narrowest.

Images