Centrifugal turbomachine

Abstract

To provide a centrifugal turbomachine capable of reducing fluid fluctuation external force causing a resonance phenomenon while suppressing deterioration of performance.SOLUTION: A centrifugal turbomachine 1 according to one embodiment comprises an impeller 2 and a plurality of outer diameter side vanes 5 arranged in a radial flow path 11 between a hub wall 32 and a shroud wall 42 for radial flow to or from the impeller 2. The outer diameter side vanes 5 are configured such that a range from one of the hub wall 32 and the shroud wall 42 to a height that is 15% to 25% of the height of the radial flow path 11 at a position where the outer diameter side vane 5 is located is uniform, and the remaining range is non-uniform.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to centrifugal turbomachinery.

Background Art

[0002] Conventionally, centrifugal turbomachinery such as centrifugal compressors, centrifugal pumps, and radial turbines has been known. Centrifugal compressors and centrifugal pumps give work to a fluid to increase its pressure, and radial turbines recover power from high-pressure fluids.

[0003] In centrifugal turbomachinery, it is common to arrange a plurality of outer-diameter-side vanes in an outer-diameter-side radial flow path for radial flow to or from an impeller. Also, a plurality of inner-diameter-side vanes may be arranged in an inner-diameter-side radial flow path for radial flow that is converted into axial flow to the impeller or axial flow from the impeller is converted. The outer-diameter-side vanes are, for example, diffuser vanes in centrifugal compressors and centrifugal pumps and nozzle vanes in radial turbines.

[0004] Upstream and downstream of the outer-diameter-side vanes or inner-diameter-side vanes, there are portions where the fluid flows easily and portions where it does not due to the presence of the vanes, so a circumferential distribution of physical quantities (low-pressure and high-pressure stripe patterns) is formed. Since the impeller rotates at high speed within the above-described circumferential distribution of physical quantities, during operation, it receives a fluid fluctuating external force at a frequency that is the product of the rotational speed and the number of vanes. When the frequency of the fluid fluctuating external force coincides with the natural vibration frequency of the impeller, a resonance phenomenon occurs.

[0005] For example, Non-Patent Document 1 describes making the diffuser vanes of a centrifugal compressor non-uniform by varying their angles. With such a configuration, it is possible to reduce the fluid fluctuating external force that causes the resonance phenomenon.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, with the structure of Non-Patent Document 1, the performance of the turbomachine deteriorates.

[0008] Therefore, an object of the present disclosure is to provide a centrifugal turbomachine that can reduce the fluid fluctuation external force that causes resonance while suppressing a decrease in performance.

Means for Solving the Problems

[0009] From a first aspect, the present disclosure provides a centrifugal turbomachine including an impeller and a plurality of outer diameter side vanes disposed in a radial flow path between a hub wall and a shroud wall for a radial flow to or from the impeller, wherein the plurality of outer diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the outer diameter side vanes are located from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform.

[0010] From a second aspect, the present disclosure provides a centrifugal turbomachine including an impeller and a plurality of inner diameter side vanes disposed in a radial flow path between a hub wall and a shroud wall for a radial flow that is converted into an axial flow to the impeller or an axial flow from the impeller is converted, wherein the plurality of inner diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the inner diameter side vanes are located from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform.

Effects of the Invention

[0011] According to the present disclosure, there is provided a centrifugal turbomachine capable of reducing a fluid fluctuating external force that causes a resonance phenomenon while suppressing a decrease in performance.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Embodiments for Carrying Out the Invention

[0013] FIG. 1 shows a centrifugal turbomachine 1 according to an embodiment. In the present embodiment, the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump that gives work to a fluid to increase the pressure. However, the centrifugal turbomachine 1 may be a radial turbine that recovers power from a high-pressure fluid.

[0014] In addition, in the present embodiment, the centrifugal turbomachine 1, which is a centrifugal compressor or a centrifugal pump, is single-stage, but the centrifugal turbomachine 1 may be multi-stage. Even when the centrifugal turbomachine 1 is a radial turbine, it may be single-stage or multi-stage.

[0015] The centrifugal turbomachine 1 includes an impeller 2, a first hub 3 disposed on the back side of the impeller 2, and a hollow first shroud 4 that houses a part of the impeller 2. In the present embodiment, the centrifugal turbomachine 1 includes a volute casing 6 connected to the first hub 3 and the first shroud 4, but the volute casing 6 may be omitted. Further, the centrifugal turbomachine 1 includes a second hub 7 disposed on the front side of the impeller 2 and a hollow second shroud 8 that houses a part of the second hub 7.

[0016] The impeller 2 includes a hub 21 whose diameter increases from the front to the back, and a plurality of blades 22 provided on the outer peripheral surface of the hub 21. The impeller 2 is fixed to a rotating shaft 23. In the present embodiment, a rolling bearing 24 that rotatably supports the rotating shaft 23 is held by the first hub 3, but a sliding bearing or a magnetic bearing may be provided on the first hub 3 instead of the rolling bearing 24.

[0017] The first hub 3 includes a disk portion 31 facing the back of the impeller 2 and a first hub wall 32 located around the disk portion 31. On the other hand, the first shroud 4 includes a flare portion 41 that curves along the blade 22 of the impeller 2 and a first shroud wall 42 located around the flare portion 41. An outer diameter side radial flow path 11 is formed between the first hub wall 32 and the first shroud wall 42. In the present embodiment, the volute casing 6 forms a volute chamber communicating with the outer diameter side radial flow path 11.

[0018] As described above, in the present embodiment, since the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump, the outer diameter side radial flow path 11 is a flow path for the radial flow from the impeller 2. When the centrifugal turbomachine 1 is a radial turbine, the outer diameter side radial flow path 11 is a flow path for the radial flow to the impeller 2.

[0019] A plurality of outer diameter side vanes 5 are arranged in the outer diameter side radial flow path 11. In the present embodiment, the outer diameter side vanes 5 are integrally provided on the first shroud wall 42, but the outer diameter side vanes 5 may be integrally provided on the first hub wall 32. In the present embodiment, since the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump as described above, the outer diameter side vanes 5 are diffuser vanes. When the centrifugal turbomachine 1 is a radial turbine, the outer diameter side vanes 5 are nozzle vanes. As shown in FIG. 2, the outer diameter side vanes 5 are arranged in a direction along the swirling flow caused by the rotation of the impeller 2.

[0020] Returning to FIG. 1, the second hub 7 includes a central portion 71 that is penetrated by the rotation axis 23 and expands in diameter as it moves away from the impeller 2, and a second hub wall 72 located around the central portion 71. The diameter of the central portion 71 on the impeller 2 side is substantially equal to the diameter of the front surface of the hub 21 of the impeller 2, and the cross-sectional shape of the outer peripheral surface of the central portion 71 is a circular or elliptical four semi-circular shape that bends approximately 90 degrees.

[0021] The second shroud 8 includes a flare portion 81 that is connected to the flare portion 41 of the first shroud 4 and is opposite to the flare portion 41, and a second shroud wall 82 located around the flare portion 81. An inner diameter side radial flow path 13 is formed between the second hub wall 72 of the second hub 7 described above and the second shroud wall 82, and a conversion flow path 12 is formed between the central portion 71 of the second hub 7 described above and the flare portion 81.

[0022] In the present embodiment, since the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump as described above, the inner diameter side radial flow path 13 is a flow path for a radially inward radial flow, and the conversion flow path 12 is a flow path that converts the radial flow into an axial flow toward the impeller 2. When the centrifugal turbomachine 1 is a radial turbine, the conversion flow path 12 is a flow path that converts the axial flow from the impeller 2 into a radial flow, and the inner diameter side radial flow path 13 is a flow path for the converted radially outward radial flow.

[0023] A plurality of inner-diameter side vanes 9 are arranged in the inner-diameter side radial flow path 13. In the present embodiment, the inner-diameter side vanes 9 are integrally provided on the second hub wall 72, but the inner-diameter side vanes 9 may be integrally provided on the second shroud wall 82. Various patterns can be adopted for the arrangement pattern of the inner-diameter side vanes 9. For example, as shown in FIG. 3A, the inner-diameter side vanes 9 may be arranged radially so as to extend in the radial direction, or may be arranged in a direction along the swirling flow caused by the rotation of the impeller 2 as shown in FIG. 3B. Alternatively, as shown in FIG. 3C, the inner-diameter side vanes 9 may be arranged radially along the radial direction on the center side while being arranged along the swirling flow on the outer peripheral side, or as shown in FIG. 3D, the inner-diameter side vanes 9 may be arranged radially along the radial direction on the outer peripheral side while being arranged along the swirling flow on the center side.

[0024] In the present embodiment, the inner-diameter side vanes 9 are evenly arranged, but the outer-diameter side vanes 5 are not evenly arranged. In other words, all the inner-diameter side vanes 9 have the same shape and are arranged in the circumferential direction at equal pitches. On the other hand, the outer-diameter side vanes 5 are different in shape as a whole.

[0025] FIG. 4 is a developed view showing the outer end face of the outer-diameter side vane 5 as viewed radially inward from the circumference passing through the outer end face of the outer-diameter side vane 5. Among the radial flows in the outer-diameter side radial flow path 11, the flow in the vicinity of the first hub wall 32 or the first shroud wall 42 has a great influence on the performance of the turbomachine 1. Which of the flows in the vicinity of the first hub wall 32 and the first shroud wall 42 affects the performance of the turbomachine 1 depends on the operating conditions of the turbomachine 1.

[0026] In the present embodiment, the flow in the vicinity of the first hub wall 32 affects the performance of the turbomachine 1. Therefore, the outer-diameter side vane 5 is configured such that the range X from the first hub wall 32 to a predetermined height h is uniform and the remaining range Y is non-uniform. The predetermined height h is 15% or more and 25% or less of the height H of the outer-diameter side radial flow path 11 at the position where the outer-diameter side vane 5 exists. When the height of the outer-diameter side radial flow path 11 changes in the range where the outer-diameter side vane 5 exists, the height H of the outer-diameter side radial flow path 11 at the position where the outer-diameter side vane 5 exists is the average height in the range where the outer-diameter side vane 5 exists.

[0027] In FIG. 5, a cross-sectional view of the outer diameter side vane 5 along the A-A line of FIG. 4 in the range X is shown by a solid line, and a cross-sectional view of the outer diameter side vane 5 along the B-B line of FIG. 4 in the range Y is shown by a broken line. Each outer diameter side vane 5 includes an inner end 5a on the side of the impeller 2 and an outer end 5b on the side opposite to the impeller 2.

[0028] As shown in FIGS. 4 and 5, in the range X, all the outer diameter side vanes 5 are arranged in the circumferential direction at an equal pitch and have the same cross-sectional shape. In the present embodiment, also in the range Y, all the outer diameter side vanes 5 have the same cross-sectional shape.

[0029] More specifically, a specific outer diameter side vane 5 is a vertical vane that is perpendicular to the first hub wall 32 and the first shroud wall 42 over the entire height. The other outer diameter side vanes 5 are bending vanes that are perpendicular to the first hub wall 32 and the first shroud wall 42 in the range X, but bend so as to approach or move away from the vertical vane as they move away from the first hub wall 32 in the range Y.

[0030] As described above, in the centrifugal turbomachine 1 of the present embodiment, since the outer diameter side vanes 5 are non-uniform except in the vicinity of the first hub wall 32, it is possible to reduce the fluid fluctuation external force that causes the resonance phenomenon. On the other hand, since the outer diameter side vanes 5 are uniform in the vicinity of the first hub wall 32, it is possible to suppress a decrease in the performance of the turbomachine 1.

[0031] <Modification Example> The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0032] For example, in the above-described embodiment, all the outer-diameter side vanes 5 had the same cross-sectional shape even in the range Y. However, as shown in FIG. 6, in the range Y, only the inner end 5a of the outer-diameter side vanes 5 other than the vertical vanes may bend so as to approach or move away from the vertical vanes as they move away from the first hub wall 32. Alternatively, as shown in FIG. 7, in the range Y, only the outer end 5b of the outer-diameter side vanes 5 other than the vertical vanes may bend so as to approach or move away from the vertical vanes as they move away from the first hub wall 32.

[0033] Furthermore, as shown in FIG. 8, all the outer-diameter side vanes 5 may have a random shape in the range Y. For example, the outer-diameter side vanes 5 that curve in the range Y and the outer-diameter side vanes 5 having different inclination angles in the range Y may be mixed. Also, as shown in FIG. 8, all the outer-diameter side vanes 5 may be inclined in the range X.

[0034] Conversely, when the flow in the vicinity of the first shroud wall 42 affects the performance of the turbomachine 1, the outer-diameter side vanes 5 may be configured such that the range from the first shroud wall 42 to a predetermined height h is uniform and the remaining range is non-uniform. Even in this case, the same effects as those of the above-described embodiment can be obtained.

[0035] Furthermore, not only the outer-diameter side vanes 5 but also the inner-diameter side vanes 9 may be configured such that a range Z1 from one of the second hub wall 72 and the second shroud wall 82 to a predetermined height hu is uniform and the remaining range Z2 is non-uniform, as shown in FIG. 9. The predetermined height hu is 15% or more and 25% or less of the height Hu of the inner-diameter side radial flow path 13 at the position where the inner-diameter side vanes 9 are present. When the height of the inner-diameter side radial flow path 13 changes in the range where the inner-diameter side vanes 9 are present, the height Hu of the inner-diameter side radial flow path 13 at the position where the inner-diameter side vanes 9 are present is the average height in the range where the inner-diameter side vanes 9 are present.

[0036] According to this configuration, while suppressing the performance degradation of the turbomachine 1, it is possible to simultaneously reduce the fluid fluctuating force generated by the inner diameter side vane 9 in addition to the fluid fluctuating force generated by the outer diameter side vane 5. Note that, similar to the outer diameter side vane 5, the inner diameter side vane 9 may be perpendicular to the second hub wall 72 and the second shroud wall 82 in the range Z1, or may be inclined. Also, in the range Z2, all the inner diameter side vanes 9 may have the same cross-sectional shape, or all the inner diameter side vanes 9 may have a random shape.

[0037] When the inner diameter side vane 9 is configured as described above, the outer diameter side vanes 5 may be evenly arranged, or the outer diameter side vanes 5 may be omitted. In this case, since the inner diameter side vanes 9 are non-uniform except in the vicinity of one of the second hub wall 72 and the second shroud wall 82, it is possible to reduce the fluid fluctuating external force that causes the resonance phenomenon. On the other hand, since the inner diameter side vanes 9 are uniform in the vicinity of one of the second hub wall 72 and the second shroud wall 82, it is possible to suppress the performance degradation of the turbomachine 1.

[0038] Further, the second hub 7 and the second shroud 8 may be omitted, and an inflow pipe or an outflow pipe may be directly connected to the flare portion 41 of the first shroud 4.

[0039] <Summary> As a first aspect, the present disclosure provides, from a first aspect, an impeller, and a plurality of outer diameter side vanes arranged in a radial flow path between a hub wall and a shroud wall for a radial flow to or from the impeller, wherein the plurality of outer diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the outer diameter side vane exists from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform, a centrifugal turbomachine.

[0040] According to the above configuration, since the outer diameter side vanes are non-uniform except in the vicinity of one of the hub wall and the shroud wall, it is possible to reduce the fluid fluctuation external force that causes the resonance phenomenon. On the other hand, since the outer diameter side vanes are uniform in the vicinity of one of the hub wall and the shroud wall, it is possible to suppress a decrease in the performance of the turbomachine.

[0041] As a second aspect, in the first aspect, the hub wall is a first hub wall, the shroud wall is a first shroud wall, and a plurality of inner diameter side vanes disposed in an inner diameter side radial flow path between a second hub wall and a second shroud wall for a radial flow that is converted into an axial flow to the impeller or the axial flow from the impeller is converted, and the plurality of inner diameter side vanes may be configured such that a range from 15% to 25% of the height of the inner diameter side radial flow path at the position where the inner diameter side vanes exist from one of the second hub wall and the second shroud wall is uniform, and the remaining range is non-uniform. According to this configuration, while suppressing a decrease in the performance of the turbomachine, it is possible to simultaneously reduce the fluid fluctuation force generated by the inner diameter side vanes in addition to the fluid fluctuation force generated by the outer diameter side vanes.

[0042] As a third aspect, the present disclosure provides a centrifugal turbomachine including an impeller and a plurality of inner diameter side vanes disposed in a radial flow path between a hub wall and a shroud wall for a radial flow that is converted into an axial flow to the impeller or the axial flow from the impeller is converted, and the plurality of inner diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the inner diameter side vanes exist from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform.

[0043] According to the above configuration, since the inner diameter side vanes are non-uniform except in the vicinity of one of the hub wall and the shroud wall, it is possible to reduce the fluid fluctuation external force that causes the resonance phenomenon. On the other hand, since the inner diameter side vanes are uniform in the vicinity of one of the hub wall and the shroud wall, it is possible to suppress a decrease in the performance of the turbomachine.

Explanation of Reference Numerals

[0044] 1 Centrifugal turbomachine 11 Outer diameter side radial flow path 13 Inner diameter side radial flow path 2 Impeller 3 First hub 32 First hub wall 4 First shroud 42 First shroud wall 5 Outer diameter side vane 7 Second hub 72 Second hub wall 8 Second shroud 82 Second shroud wall 9 Inner diameter side vane

Claims

1. An impeller, and a plurality of outer diameter side vanes disposed in a radial flow path between a hub wall and a shroud wall for a radial flow to or from the impeller, wherein the plurality of outer diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the outer diameter side vanes are located from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform, a centrifugal turbomachine.

2. The hub wall is a first hub wall, and the shroud wall is a first shroud wall, and a plurality of inner diameter side vanes disposed in an inner diameter side radial flow path between a second hub wall and a second shroud wall for a radial flow that is converted into an axial flow to the impeller or an axial flow from the impeller is converted, wherein the plurality of inner diameter side vanes are configured such that a range from 15% to 25% of the height of the inner diameter side radial flow path at the position where the inner diameter side vanes are located from one of the second hub wall and the second shroud wall is uniform, and the remaining range is non-uniform, the centrifugal turbomachine according to claim 1.

3. An impeller, and a plurality of inner diameter side vanes disposed in a radial flow path between a hub wall and a shroud wall for a radial flow that is converted into an axial flow to the impeller or an axial flow from the impeller is converted, wherein the plurality of inner diameter side vanes are configured such that a range from 15% to 25% of the height of the radial flow path at the position where the inner diameter side vanes are located from one of the hub wall and the shroud wall is uniform, and the remaining range is non-uniform, a centrifugal turbomachine.

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