Centrifugal turbomachine

Abstract

A centrifugal turbomachine (1) according to one embodiment includes an impeller (2), and a plurality of outer diameter-side vanes (5) disposed in a radial flow path (11) for radial flow to the impeller (2) or from the impeller (2) between a hub wall (32) and a shroud wall (42). The outer diameter-side vanes (5) are configured such that the range from the hub wall (32) or the shroud wall (42) to a height of 15-25% inclusive within the height of the radial flow path (11) is uniform at the positions where the outer diameter-side vanes (5) are present, and the remaining range is non-uniform.

Description

centrifugal turbomachinery

[0001] The present disclosure relates to centrifugal turbomachines.

[0002] Conventionally, centrifugal turbomachines such as centrifugal compressors, centrifugal pumps, and radial turbines have been known. Centrifugal compressors and centrifugal pumps apply work to a fluid to increase its pressure, while radial turbines recover power from the high-pressure fluid.

[0003] In centrifugal turbomachines, outer vanes are typically located in the outer radial passage for radial flow to or from the impeller, and inner vanes may be located in the inner radial passage for radial flow that is converted to axial flow to or from the impeller. Outer vanes are, for example, diffuser vanes in centrifugal compressors and pumps, and nozzle vanes in radial turbines.

[0004] Upstream and downstream of the outer or inner vanes, there are areas where the fluid flows easily and areas where it does not, due to the presence of the vanes, and a distribution of physical quantities (striped pattern of low and high pressure) is formed in the circumferential direction. Because the impeller rotates at high speed within the above-mentioned distribution of physical quantities in the circumferential direction, it is subjected to a fluid fluctuation external force with a frequency equal to the product of the rotation speed and the number of vanes during operation. When the frequency of the fluid fluctuation external force matches the natural frequency of the impeller, a resonance phenomenon occurs.

[0005] For example, Non-Patent Document 1 describes that the angles of the diffuser vanes of a centrifugal compressor are made different to make them non-uniform. This configuration can reduce the fluid fluctuation external force that causes the resonance phenomenon.

[0006] Shimohara, et al., "Study on Blade Vibration of Centrifugal Compressor," International Gas Turbine Society, IGTC-2019-135, November 17-22, 2019

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

[0008] Therefore, an object of the present disclosure is to provide a centrifugal turbomachine that can reduce fluid fluctuation external forces that cause resonance phenomena while suppressing performance degradation.

[0009] From a first aspect, the present disclosure provides a centrifugal turbomachine comprising: an impeller; and a plurality of outer diameter vanes arranged in a radial flow passage between a hub wall and a shroud wall for radial flow to or from the impeller, wherein the plurality of outer diameter vanes are configured to be uniform over a range from one of the hub wall and the shroud wall to a height that is 15% to 25% of the height of the radial flow passage at the location of the outer diameter vane, and to be non-uniform over the remaining range.

[0010] From a second aspect, the present disclosure provides a centrifugal turbomachine comprising: an impeller; and a plurality of inner diameter vanes arranged in a radial flow passage between a hub wall and a shroud wall for radial flow that is converted into axial flow to the impeller or into which axial flow from the impeller is converted, the plurality of inner diameter vanes being configured so that a range from one of the hub wall and the shroud wall to a height that is 15% to 25% of the height of the radial flow passage at a position where the inner diameter vane is present is uniform, and the remaining range is non-uniform.

[0011] According to the present disclosure, a centrifugal turbomachine is provided that can reduce fluid fluctuation external forces that cause resonance phenomena while suppressing performance degradation.

[0012] 4A to 4D are views showing an arrangement pattern of inner diameter side vanes; a development showing the outer end surfaces of outer diameter side vanes, viewed radially inward from a circumference passing through the outer end surfaces of the outer diameter side vanes; a cross-sectional view taken along lines A-A and B-B in FIG. 4; a cross-sectional view of outer diameter side vanes of a first modified example taken at positions corresponding to lines A-A and B-B in FIG. 4; a cross-sectional view of outer diameter side vanes of a second modified example taken at positions corresponding to lines A-A and B-B in FIG. 4; a development showing outer end surfaces of outer diameter side vanes, viewed radially inward from a circumference passing through the outer end surfaces of the outer diameter side vanes, viewed radially inward from a circumference passing through the outer end surfaces of the inner diameter side vanes, when the inner diameter side vanes are not uniformly arranged;

[0013] 1 shows a centrifugal turbomachine 1 according to one embodiment. In this embodiment, the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump that applies work to a fluid to increase its pressure. However, the centrifugal turbomachine 1 may also be a radial turbine that recovers power from a high-pressure fluid.

[0014] In addition, in this embodiment, the centrifugal turbomachine 1, which is a centrifugal compressor or a centrifugal pump, has a single stage, but the centrifugal turbomachine 1 may have multiple stages. When the centrifugal turbomachine 1 is a radial turbine, it may also have a single stage or multiple stages.

[0015] The centrifugal turbomachine 1 includes an impeller 2, a first hub 3 arranged on the back side of the impeller 2, and a hollow first shroud 4 that houses a portion of the impeller 2. In this 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. Furthermore, the centrifugal turbomachine 1 includes a second hub 7 arranged on the front side of the impeller 2, and a hollow second shroud 8 that houses a portion of the second hub 7.

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

[0017] The first hub 3 includes a disk portion 31 facing the back surface 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 flared portion 41 curved along the blades 22 of the impeller 2, and a first shroud wall 42 located around the flared portion 41. An outer diameter side radial flow passage 11 is formed between the first hub wall 32 and the first shroud wall 42. In this embodiment, the volute casing 6 forms a volute chamber that communicates with the outer diameter side radial flow passage 11.

[0018] In this embodiment, as described above, the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump, and therefore the outer-diameter radial flow passage 11 is a flow passage for radial flow from the impeller 2. If the centrifugal turbomachine 1 is a radial turbine, the outer-diameter radial flow passage 11 is a flow passage for radial flow to the impeller 2.

[0019] A plurality of outer diameter side vanes 5 are arranged in the outer diameter side radial flow passage 11. In this embodiment, the outer diameter side vanes 5 are provided integrally with the first shroud wall 42, but the outer diameter side vanes 5 may be provided integrally with the first hub wall 32. In this embodiment, as described above, the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump, and therefore the outer diameter side vanes 5 are diffuser vanes. If 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] 1, the second hub 7 includes a central portion 71 that is penetrated by the rotary shaft 23 and that increases in diameter as it moves away from the impeller 2, and a second hub wall 72 that is located around the central portion 71. The diameter of the central portion 71 on the impeller 2 side is approximately equal to the diameter of the front of the hub 21 of the impeller 2, and the cross-sectional shape of the outer circumferential surface of the central portion 71 is a quarter circle or ellipse that is bent at 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 faces in the opposite direction to the flare portion 41, and a second shroud wall 82 that is positioned around the flared portion 81. An inner diameter-side radial flow passage 13 is formed between the second hub wall 72 of the second hub 7 and the second shroud wall 82, and a conversion flow passage 12 is formed between the central portion 71 of the second hub 7 and the flare portion 81.

[0022] In this embodiment, as described above, the centrifugal turbomachine 1 is a centrifugal compressor or a centrifugal pump, and therefore the inner diameter-side radial flow passage 13 is a flow passage for a radially inward radial flow, and the conversion flow passage 12 is a flow passage that converts the radial flow into an axial flow to the impeller 2. In the case where the centrifugal turbomachine 1 is a radial turbine, the conversion flow passage 12 is a flow passage that converts the axial flow from the impeller 2 into a radial flow, and the inner diameter-side radial flow passage 13 is a flow passage for the converted radially outward radial flow.

[0023] A plurality of inner vanes 9 are arranged in the inner radial flow passage 13. In this embodiment, the inner vanes 9 are integrally formed with the second hub wall 72, but the inner vanes 9 may also be integrally formed with the second shroud wall 82. Various arrangement patterns of the inner vanes 9 can be employed. For example, the inner vanes 9 may be arranged radially so as to extend in the radial direction as shown in FIG. 3A , or may be arranged so as to follow the swirling flow caused by the rotation of the impeller 2 as shown in FIG. 3B . Alternatively, the inner vanes 9 may be arranged radially along the radial direction on the central side as shown in FIG. 3C and along the swirling flow on the outer periphery, or may be arranged radially along the radial direction on the outer periphery and along the swirling flow on the central side as shown in FIG. 3D .

[0024] In this embodiment, the inner vanes 9 are evenly spaced, but the outer vanes 5 are not evenly spaced. In other words, the inner vanes 9 all have the same shape and are arranged at equal intervals in the circumferential direction. On the other hand, the outer vanes 5 have different shapes overall.

[0025] 4 is a development view showing the outer end surface of the outer diameter side vane 5, viewed radially inward from a circumference passing through the outer end surface of the outer diameter side vane 5. Of the radial flows in the outer diameter side radial flow passage 11, the flows near the first hub wall 32 or the first shroud wall 42 have a significant impact on the performance of the turbomachine 1. Whether the flows near the first hub wall 32 or the first shroud wall 42 have an impact on the performance of the turbomachine 1 depends on the operating conditions of the turbomachine 1.

[0026] In this embodiment, the flow near the first hub wall 32 affects the performance of the turbomachine 1. For this reason, the outer diameter side vane 5 is configured so 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% to 25% of the height H of the outer diameter side radial flow passage 11 at the position where the outer diameter side vane 5 is located. If the height of the outer diameter side radial flow passage 11 varies within the range where the outer diameter side vane 5 is located, the height H of the outer diameter side radial flow passage 11 at the position where the outer diameter side vane 5 is located is the average height within the range where the outer diameter side vane 5 is located.

[0027] 5 shows a cross section of the outer diameter side vane 5 taken along line A-A in FIG. 4 in range X by a solid line, and a cross section of the outer diameter side vane 5 taken along line B-B in FIG. 4 in range Y by a dashed line. Each outer diameter side vane 5 includes an inner end 5a on the impeller 2 side and an outer end 5b on the opposite side from the impeller 2.

[0028] 4 and 5, in range X, all of the outer diameter side vanes 5 are arranged at equal pitches in the circumferential direction and have the same cross-sectional shape. In this embodiment, in range Y, all of the outer diameter side vanes 5 also have the same cross-sectional shape.

[0029] More specifically, certain outer diameter vanes 5 are vertical vanes that are perpendicular to the first hub wall 32 and the first shroud wall 42 over their entire height. Other outer diameter vanes 5 are curved vanes that are perpendicular to the first hub wall 32 and the first shroud wall 42 in range X, but bend toward or away from the vertical vanes as they move away from the first hub wall 32 in range Y.

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

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

[0032] For example, in the above embodiment, all of the outer diameter vanes 5 have the same cross-sectional shape even in the range Y. However, as shown in Fig. 6, in the range Y, only the inner ends 5a of the outer diameter vanes 5 other than the vertical vanes may be bent so as to approach or move away from the vertical vanes as the distance from the first hub wall 32 increases. Alternatively, as shown in Fig. 7, in the range Y, only the outer ends 5b of the outer diameter vanes 5 other than the vertical vanes may be bent so as to approach or move away from the vertical vanes as the distance from the first hub wall 32 increases.

[0033] Furthermore, as shown in Fig. 8, all of the outer diameter side vanes 5 may have random shapes in range Y. For example, there may be a mixture of outer diameter side vanes 5 that are curved in range Y and outer diameter side vanes 5 that have different inclination angles in range Y. Furthermore, as shown in Fig. 8, all of the outer diameter side vanes 5 may be inclined in range X.

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

[0035] Furthermore, not only the outer vane 5 but also the inner vane 9 may be configured so that the range Z1 from either the second hub wall 72 or the second shroud wall 82 to a predetermined height hu is uniform, and the remaining range Z2 is non-uniform, as shown in Figure 9. The predetermined height hu is 15% to 25% of the height Hu of the inner radial flow passage 13 at the position where the inner vane 9 is located. If the height of the inner radial flow passage 13 varies within the range where the inner vane 9 is located, the height Hu of the inner radial flow passage 13 at the position where the inner vane 9 is located is the average height within the range where the inner vane 9 is located.

[0036] This configuration makes it possible to simultaneously reduce the fluid fluctuation force generated by the inner vanes 9 in addition to the fluid fluctuation force generated by the outer vanes 5 while suppressing a deterioration in the performance of the turbomachine 1. Note that, like the outer vanes 5, the inner vanes 9 may be perpendicular to or inclined from the second hub wall 72 and the second shroud wall 82 in range Z1. Furthermore, in range Z2, all of the inner vanes 9 may have the same cross-sectional shape, or all of the inner vanes 9 may have random shapes.

[0037] When the inner diameter side vanes 9 are configured as described above, the outer diameter side vanes 5 may be arranged uniformly, or the outer diameter side vanes 5 may be omitted. In this case, the inner diameter side vanes 9 are uneven except near one of the second hub wall 72 and the second shroud wall 82, so that the fluid fluctuation external force that causes the resonance phenomenon can be reduced. On the other hand, the inner diameter side vanes 9 are uniform near one of the second hub wall 72 and the second shroud wall 82, so that a decrease in the performance of the turbomachine 1 can be suppressed.

[0038] Also, the second hub 7 and the second shroud 8 may be omitted, and the inlet pipe or the outlet pipe may be directly connected to the flared portion 41 of the first shroud 4 .

[0039] <Summary> In a first aspect, the present disclosure provides a centrifugal turbomachine comprising: an impeller; and a plurality of outer diameter vanes arranged in a radial flow passage between a hub wall and a shroud wall for radial flow to or from the impeller, wherein the plurality of outer diameter vanes are uniformly spaced from one of the hub wall and the shroud wall to a height that is 15% to 25% of the height of the radial flow passage at the location of the outer diameter vane, and are non-uniformly spaced from the remaining height.

[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, while 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 deterioration in the performance of the turbomachine.

[0041] In a second aspect, in the first aspect, the hub wall may be a first hub wall, the shroud wall may be a first shroud wall, and a plurality of inner diameter vanes may be disposed in an inner diameter radial passage 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 into which the axial flow from the impeller is converted, the plurality of inner diameter vanes may be configured to be uniform in height over a range from one of the second hub wall and the second shroud wall to a height that is 15% to 25% of the height of the inner diameter radial passage at the position where the inner diameter vane is located, and to be non-uniform in the remaining range. With this configuration, it is possible to simultaneously reduce the fluid fluctuating forces generated by the inner diameter vanes in addition to the fluid fluctuating forces generated by the outer diameter vanes while suppressing a deterioration in performance of the turbomachine.

[0042] In a third aspect, from a second aspect, the present disclosure provides a centrifugal turbomachine comprising: an impeller; and a plurality of inner diameter vanes arranged in a radial flow passage between a hub wall and a shroud wall for radial flow that is converted into axial flow to the impeller or into which axial flow from the impeller is converted, the plurality of inner diameter vanes being configured so that the height of the plurality of inner diameter vanes is uniform over a range from one of the hub wall and the shroud wall to a height that is 15% to 25% of the height of the radial flow passage at the location of the inner diameter vane, 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, while 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 deterioration in the performance of the turbomachine.

Claims

1. A centrifugal turbomachine comprising: an impeller; and a plurality of outer diameter vanes disposed in a radial flow passage between a hub wall and a shroud wall for radial flow to or from said impeller, said plurality of outer diameter vanes being configured so that the vanes are uniform over a range from one of the hub wall and the shroud wall to a height that is 15% to 25% of the height of said radial flow passage at the location of said outer diameter vanes, and the remaining range is non-uniform.

2. A centrifugal turbomachine as set forth in claim 1, wherein the hub wall is a first hub wall, the shroud wall is a first shroud wall, and the centrifugal turbomachine is provided with a plurality of inner diameter side vanes arranged in an inner diameter side radial flow passage between the second hub wall and the second shroud wall for radial flow that is converted into an axial flow to the impeller or into which the axial flow from the impeller is converted, the plurality of inner diameter side vanes being configured so that they are uniform in a range from one of the second hub wall and the second shroud wall to a height that is 15% to 25% of the height of the inner diameter side radial flow passage at a position where the inner diameter side vane is present, and the remaining range is non-uniform.

3. A centrifugal turbomachine comprising: an impeller; and a plurality of inner diameter side vanes arranged in a radial flow passage between a hub wall and a shroud wall for radial flow that is converted into axial flow to said impeller or into which axial flow from said impeller is converted, said plurality of inner diameter side vanes being configured so that the range from one of said hub wall and said shroud wall to a height of 15% to 25% of the height of said radial flow passage at the position where said inner diameter side vanes are present is uniform, and the remaining range is non-uniform.

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