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WO2025154678A1 - Machine à fluide centrifuge à étages multiples - Google Patents

Machine à fluide centrifuge à étages multiples

Info

Publication number
WO2025154678A1
WO2025154678A1 PCT/JP2025/000685 JP2025000685W WO2025154678A1 WO 2025154678 A1 WO2025154678 A1 WO 2025154678A1 JP 2025000685 W JP2025000685 W JP 2025000685W WO 2025154678 A1 WO2025154678 A1 WO 2025154678A1
Authority
WO
WIPO (PCT)
Prior art keywords
flow passage
return
outlet
impeller
diffuser
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/000685
Other languages
English (en)
Japanese (ja)
Inventor
澄賢 平舘
竜一 橋本
雅弘 岡田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Industrial Products Ltd
Original Assignee
Hitachi Industrial Products Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Industrial Products Ltd filed Critical Hitachi Industrial Products Ltd
Publication of WO2025154678A1 publication Critical patent/WO2025154678A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D17/08—Centrifugal pumps
    • F04D17/10—Centrifugal pumps for compressing or evacuating
    • F04D17/12—Multi-stage pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers

Definitions

  • the present invention relates to a multi-stage centrifugal fluid machine having multiple impellers, and in particular to the shape of the stationary flow passage of each stage of the multi-stage centrifugal fluid machine.
  • single-shaft multi-stage centrifugal compressors with multiple centrifugal impellers on one rotating shaft are used to boost the pressure of process gas.
  • This single-shaft multi-stage centrifugal compressor is configured to suck in process gas from a suction nozzle that forms a suction passage, introduce it into the inside of the annular passage, compress and boost the gas sequentially using the centrifugal impellers on the rotating shaft in multiple stages, and then discharge it from a discharge nozzle.
  • These single-shaft multi-stage centrifugal compressors are required to be highly efficient and ensure stable operation over a wide range of flow rates (hereinafter referred to as a wide operating range).
  • VL vaneless passages
  • Patent Document 1 A conventional example of a single-shaft multi-stage centrifugal compressor in which the diffuser passage is configured as a VL is described in Patent Document 1.
  • the diffuser of the single-shaft multi-stage centrifugal compressor is configured as a VL
  • a return passage is provided that is composed of a return bend section that is located downstream of the diffuser and guides the flow discharged from the diffuser in the radially outward direction in the radially inward direction, and a return vane section that guides the flow from the return bend section to the next stage impeller while removing the swirling component.
  • an axis-parallel passage is provided in the return bend section, and a blade is provided in part of this axis-parallel passage to remove the swirling of the flow.
  • the inflow angle of the flow to the leading edge of the return vane becomes larger. This reduces the swirling component of the flow that needs to be removed between the return vane inlet and outlet, so the blade angle difference between the return vane inlet and outlet, i.e. the blade loading, can be reduced, ensuring ease of design of the return vane and improving the performance of the next stage compressor.
  • Patent Document 1 an axially parallel section is provided on either the inside or outside flow channel wall of the bend, and vanes are provided in this section to eliminate flow swirl, and the flow channel width is configured to increase downstream.
  • Patent Document 1 aiming to reduce the wall friction loss of the fluid in the bend section and the blade load of the return vane, an axially parallel flow passage is provided in the bend section, a blade is installed there to remove the swirl of the flow, and the flow passage width near the blade installation is expanded.
  • the deviation of the operating flow rate of the compressor from the rated flow rate becomes large, the deviation between the flow angle of the flow flowing into the blade installed in the bend section and the inlet blade angle of the blade becomes large, causing separation on the blade surface, narrowing the stable operating flow rate range of the single-shaft multi-stage centrifugal compressor.
  • both the diffuser section and the bend section are configured as VLs to widen the operating range, the swirl of the flow will not be sufficiently removed before it flows into the leading edge of the return vane. In this case, it is necessary to fully remove the swirl between the inlet and outlet of the return vane, and it becomes necessary to increase the blade load of the return vane. An increase in the blade loading of the return vane in turn leads to separation of the flow in the passage between the return vanes, making the design of the return vane difficult. Therefore, the present invention provides a multi-stage centrifugal fluid machine that can achieve both a wide operating range and easy return vane design.
  • the multi-stage centrifugal fluid machine of the present invention is a multi-stage centrifugal fluid machine having a plurality of impellers, a rotating shaft on which the plurality of impellers are attached, and a stationary flow passage provided downstream of the impellers and guiding a fluid that has passed through the outlet of the impeller to the impeller of the subsequent stage, the stationary flow passage comprising a diffuser provided radially outside the impeller, a return flow passage that guides the fluid from the diffuser to the impeller of the subsequent stage, and a plurality of return vanes provided in the return flow passage and spaced apart in the circumferential direction, the return flow passage directing the fluid that has passed through the diffuser radially inward
  • the return bend has a first curved portion that turns the fluid from the radially outward direction to the same direction as the rotation axis, and a second curved portion that is located downstream of the first curved portion and turns the fluid from the same direction as the rotation axis to the radially in
  • the multi-stage centrifugal fluid machine is a multi-stage centrifugal fluid machine having a plurality of impellers, a rotating shaft to which the plurality of impellers are attached, and a stationary flow passage provided downstream of the impellers to guide a fluid that has passed through the outlet of the impeller to the impeller of the subsequent stage, the stationary flow passage having a diffuser provided radially outside the impeller, a return flow passage that guides a fluid from the diffuser to the impeller of the subsequent stage, and a plurality of return vanes provided in the return flow passage and arranged at intervals along the circumferential direction, the return flow passage having a return vane that guides the fluid that has passed through the diffuser radially inward.
  • FIG. 1 is a diagram showing an example of the results of a study on the extent to which the absolute flow angle changes when the outlet diameter of a flow passage having a flow passage width narrower than that of the impeller outlet is changed in the single-shaft multi-stage centrifugal compressor according to the first embodiment of the present invention.
  • FIG. 2 is a meridional cross-sectional view of the vicinity of a return bend in the single-shaft multi-stage centrifugal compressor according to the first embodiment of the present invention, in which a first curved portion of the return bend is not formed as an expanded flow passage.
  • FIG. 6 is a meridional cross-sectional view of a single-shaft multi-stage centrifugal compressor in the vicinity of a return bend according to a second embodiment of the present invention.
  • FIG. 11 is a meridional cross-sectional view of a modified example of a single-shaft multi-stage centrifugal compressor according to a second embodiment of the present invention, in the vicinity of a return bend.
  • FIG. 11 is a meridional cross-sectional view of a single-shaft multi-stage centrifugal compressor according to a third embodiment of the present invention, in the vicinity of a return bend.
  • a single-shaft multi-stage centrifugal compressor 20 will be described as an example of a general multi-stage centrifugal fluid machine with reference to Figure 1.
  • the single-shaft multi-stage centrifugal compressor 20 is roughly composed of a centrifugal impeller 1 that imparts rotational energy to a fluid, a rotating shaft 4 to which the centrifugal impeller 1 is attached, and a diffuser 5 that is located radially outside the centrifugal impeller 1 and converts the dynamic pressure of the fluid flowing out from the centrifugal impeller 1 into static pressure.
  • a return flow path 6 is provided downstream of the diffuser 5 to guide the fluid to the subsequent centrifugal impeller 1.
  • the centrifugal impeller 1 has a disk (hub) 2 that is fastened to a rotating shaft 4, a side plate (shroud) 3 that is arranged opposite the hub 2, and a number of blades 1A that are located between the hub 2 and the shroud 3 and spaced apart in the circumferential direction (perpendicular to the plane of the paper in FIG. 1). Note that while FIG. 1 shows a closed-type impeller with a shroud 3, an open-type impeller without a shroud 3 may be used instead.
  • the diffuser 5 refers to a region of radially outward flow immediately downstream of the outlet 1B of the centrifugal impeller 1.
  • the diffuser 5 may be either a vaned diffuser having a plurality of blades arranged at approximately equal pitch in the circumferential direction, or a vaneless diffuser having no blades (not shown in FIG. 1).
  • the return flow passage 6 is composed of a return bend 7 and a return vane 8, and the return bend 7 redirects the fluid that has passed through the diffuser 5 from an outward radial direction to an inward radial direction, and the return vane 8 removes the swirling component of the fluid, rectifying the fluid while allowing it to flow into the centrifugal impeller 1 of the next stage.
  • the return bend 7 is formed as a U-shaped curved passage surrounded by surrounding structures in the meridian plane, and its return bend inlet 9 is defined by a substantially cylindrical surface corresponding to the outlet of the diffuser 5, and its return bend outlet 10 is defined as a section from the return bend inlet 9 to the return bend outlet 10, which is defined by a substantially cylindrical surface corresponding to the end of the meridian plane curved passage located immediately upstream of the return vane leading edge 11.
  • the return bend 7 includes a return bend first curved portion 12 located upstream of the return bend 7 and redirecting the working gas (fluid) from the radially outward direction to the same direction as the rotating shaft 4, and a return bend second curved portion 13 located downstream of the return bend first curved portion 12 and redirecting the working gas (fluid) from the same direction as the rotating shaft 4 to the radially inward direction.
  • the return vane 8 is composed of a plurality of blades arranged at substantially equal pitches in the circumferential direction around the rotating shaft 4.
  • the aforementioned diffuser 5 and the return passage 6 consisting of the return bend 7 and the return vane 8 are collectively referred to as the stationary passage 14 .
  • FIG. 2 shows a single-shaft multi-stage centrifugal compressor 20 in which the compression stages shown in FIG. 1 are stacked in the axial direction.
  • radial bearings 17 that rotatably support the rotating shaft 4 are arranged on both ends of the rotating shaft 4, and a thrust bearing 18 that supports the rotating shaft 4 in the axial direction is arranged on one end of the rotating shaft 4.
  • centrifugal impellers 1 of multiple compression stages (five centrifugal impellers in FIG. 2) are fixedly attached to the rotating shaft 4, and a diffuser 5 and a return flow passage 6 are provided downstream of each centrifugal impeller 1, as shown in FIG. 1.
  • the centrifugal impellers 1, the diffuser 5, and the return flow passage 6 are housed in a casing 19.
  • a suction flow passage 15 is provided on the suction side of the casing 19
  • a discharge flow passage 16 is provided on the discharge side of the casing 19.
  • Figure 3 is a meridional cross section near the return bend of the single-shaft multi-stage centrifugal compressor according to the first embodiment of the present invention. That is, Figure 3 is a meridional cross section taken from near the outlet 1B of the centrifugal impeller 1 to the downstream diffuser 5 and return bend 7, and near the leading edge 11 of the return vane 8 in the single-shaft multi-stage centrifugal compressor 20 in this embodiment.
  • the diffuser 5 and the return bend 7 of the stationary flow passage 14 are configured as VLs, and further, the stationary flow passage 14 between the inlet of the diffuser 5 and the outlet 10 of the return bend 7 is configured as a constant region 21 having a flow passage width b3 narrower than the flow passage width b2 at the outlet of the centrifugal impeller 1 on the upstream side, and an expanded flow passage 22 having a larger flow passage width than that on the downstream side.
  • the single-shaft multi-stage centrifugal compressor 20 can have a wide operating range by configuring the diffuser 5 and the return bend 7 with VL.
  • FIG. 4 shows a velocity triangle of the flow near the side wall 23 of the flow passage 21 (FIG. 3) with a constant flow passage width b3 narrower than the flow passage width b2 at the outlet of the centrifugal impeller 1, which corresponds to the upstream side of the stationary flow passage 14 (FIG. 3) when this embodiment is applied, with a solid line arrow.
  • the dashed line arrow in the figure shows a velocity triangle near the side wall 23 in the case where the flow passage width is not reduced compared to the flow passage width b2 at the outlet 1B of the centrifugal impeller 1, shown for comparison.
  • FIG. 3 shows a velocity triangle of the flow near the side wall 23 of the flow passage 21 (FIG. 3) with a constant flow passage width b3 narrower than the flow passage width b2 at the outlet of the centrifugal impeller 1, which corresponds to the upstream side of the stationary flow passage 14 (FIG. 3) when this embodiment is applied, with a solid line arrow.
  • the velocity gradient in the direction perpendicular to the wall surface of the side wall 23 increases, and the wall friction acting on the working fluid (fluid) from the side wall 23 increases.
  • the angular momentum is significantly reduced, particularly near the inlet of the diffuser 5 where the size of Cu is larger, and it becomes possible to efficiently reduce the circumferential component Cu, i.e., the swirling component of the flow.
  • the absolute flow angle ⁇ also increases due to the increase in the Cm component and the decrease in the Cu component described above.
  • the efficiency of the single-shaft multi-stage centrifugal compressor 20 will decrease if left as is. Therefore, in this embodiment, the flow passage between the outlet downstream of the constant flow passage width region 21, which has a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage 14, and the return bend outlet 10 is made into an enlarged flow passage region 22, which has an increased flow passage width along the downstream flow direction.
  • the flow velocity of the working gas (fluid) is reduced downstream of the constant flow passage width region 21, which has a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage, and the effect of increased loss caused by the reduced flow passage width on the upstream side of the stationary flow passage 14 is countered, making it possible to maintain and improve the stage efficiency.
  • FIG. 5 shows the inlet velocity triangle of the return vane 8 and the blade cross-sectional shape of the return vane when this embodiment is applied.
  • a constant flow passage width region 21 which has a narrower flow passage width than the impeller outlet, is provided on the upstream side of the stationary flow passage 14 (FIG. 3), thereby significantly reducing the swirling component of the working gas (fluid) and increasing ⁇ in the region 21.
  • the inflow angle ⁇ of the working gas (fluid) in the velocity triangle at the leading edge 11 of the return vane 8 becomes large. Therefore, the inlet angle ⁇ b 5 of the return vane 8, which is set to match the inflow angle ⁇ of the fluid into the return vane 8, can be increased.
  • the return vane trailing edge 8TE is generally set to face the direction of the rotation shaft 4 in order to eliminate the swirling of the working gas (fluid). As described above, the turning of the fluid from the return vane leading edge 11 to the return vane trailing edge 8TE can be reduced, so that the ease of design of the return vane 8 can be maintained.
  • the horizontal axis shows the ratio of the radius ratio R34/R2, where R2 is the radius at the outlet 1B of the centrifugal impeller 1 and R34 is the outlet radius of the constant flow width region 21, which has a narrower flow width than the impeller outlet on the upstream side of the stationary flow path, to the radius ratio R4 /R2 between the radii R4 and R2 of the return bend inlet 9 when the VL diffuser 5 is configured as a constant flow path section that does not narrow the flow path width relative to the flow path width b2 of the impeller outlet 1B .
  • the region where the vertical axis is larger than 0° is the region where the effect of increasing the flow angle is obtained by narrowing the flow passage width relative to the impeller outlet flow passage width b 2 in constant flow passage width region 21 where the flow passage width is narrower than the impeller outlet on the upstream side of the stationary flow passage.
  • the flow passage width b3 of the constant flow passage width region 21, which is narrower than the impeller outlet on the upstream side of the stationary flow passage is set to 70% of the flow passage width b2 at the impeller outlet, and the flow passage width is increased to 1.2 times the flow passage width b3 at the diffuser inlet on the downstream side.
  • the larger the horizontal axis is, that is, the larger the outlet radius R34 of the constant flow passage width region 21, which is narrower than the impeller outlet on the upstream side of the stationary flow passage 14, the larger ⁇ becomes, and the effect of increasing the absolute flow angle becomes larger.
  • the flow turning angle by the blades installed in the diffuser 5 and return bend 7 is generally set to about several degrees.
  • the insufficient turning angle due to the absence of the vanes (vaneless: VL) is set to 5°, and the horizontal axis position (approximately 0.88) at which the insufficient turning angle can be compensated for by reducing the flow passage width in the constant flow passage width region 21, which is narrower than the impeller outlet on the upstream side of the stationary flow passage, is shown by a vertical dotted line. That is, in this case, if the flow passage width is narrowed to a position of 88% of the radius R4 of the return bend inlet 9, the insufficient turning angle due to the diffuser 5 and return bend 7 being configured with VL can be sufficiently compensated for.
  • the range of R34 / R4 in which the same effect can be obtained is approximately 0.5 to 1.0. Therefore, it is preferable to set R34 / R4 in this range.
  • the flow passage from the outlet downstream of the constant flow passage width region 21, which has a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage, to the return bend outlet 10 is an expanded flow passage with a gradually increasing flow passage width in the downstream direction.
  • the return bend first curved portion 12 of the return bend 7 may be configured to have a constant flow passage width (constant at flow passage width b4 in Fig. 7) instead of being an expanded flow passage.
  • the single-shaft multi-stage centrifugal compressor 20 described in this embodiment is expected to be applied to various plants.
  • a synthesis plant for ammonia, methanol, etc. is one example where the single-shaft multi-stage centrifugal compressor 20 to be installed is required to maintain the rated discharge pressure while ensuring stable operation in a wide flow rate range from the rated flow rate to the small flow rate side.
  • the synthesis gas compressor used in these plants is required to operate stably in a wide flow rate range from the rated flow rate to the small flow rate side in accordance with the desired gas synthesis amount while maintaining the gas pressure required for the synthesis of ammonia or methanol.
  • Fig. 8 is a meridian section near a return bend of a single-shaft multi-stage centrifugal compressor according to a second embodiment of the present invention.
  • Fig. 9 is a meridian section near a return bend showing a modified example of a single-shaft multi-stage centrifugal compressor according to the second embodiment of the present invention.
  • This embodiment differs from the first embodiment in that a constant flow passage width region 21, which has a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage, includes a first curved portion 12 of the return bend 7 and a part of the return bend 7 in addition to the diffuser 5.
  • the same components as those in the first embodiment are denoted by the same reference numerals. Specifically, FIG.
  • the diffuser 5 and the return bend 7 of the stationary flow passage 14 are formed as VLs, as in the first embodiment, and the stationary flow passage 14 between the inlet of the diffuser 5 and the outlet 10 of the return bend 7 is formed as a constant flow passage 21 with a flow passage width b3 narrower than the flow passage width b2 at the outlet 1B of the centrifugal impeller 1 on the upstream side, and an expanded flow passage 22 with a flow passage width wider than that on the downstream side.
  • At least a part of the meridian shape of the flow passage on the inner or outer diameter side between the outlet 12B of the first curved portion 12 of the return bend 7 and the inlet 13A of the second curved portion 13 is an axial flow passage portion 24 in the return bend extending in the same direction as the extending direction of the rotating shaft 4.
  • the outlet 21B of the region 21 having a constant flow path width b3 narrower than the flow path width b2 at the outlet 1B of the centrifugal impeller 1 is configured to be located within the return bend 7 between the outlet 12B of the first curved portion 12 of the return bend 7 and the inlet 13A of the second curved portion 13 of the return bend 7.
  • the outlet 21B of the region 21 having a constant flow path width b3 narrower than the flow path width b2 at the outlet 1B of the centrifugal impeller 1 is located within the return bend 7 between the outlet 12B of the first curved portion 12 of the return bend 7 and the inlet 13A of the second curved portion 13 of the return bend 7.
  • the region 21 having a constant flow path width b3 narrower than the flow path width b2 at the outlet 1B of the centrifugal impeller 1 includes the diffuser 5, the first curved portion 12 of the return bend 7, and a part of the return bend 7.
  • the diffuser 5 and return bend 7 are configured as VLs, which allows the single-shaft multi-stage centrifugal compressor 20 to have a wide operating range.
  • the wall friction acting on the working fluid (fluid) from the side wall 23 increases. This makes it possible to efficiently reduce the swirling component of the flow.
  • the absolute flow angle ⁇ can also be increased by increasing the Cm component and decreasing the Cu component, ensuring ease of design of the return vane 8.
  • the effect of increased loss due to the reduction in the flow passage width in the constant flow passage width region 21, where the flow passage width is narrower than the impeller outlet on the upstream side of the stationary flow passage, can be countered, and the stage efficiency can be maintained and improved.
  • an axial flow passage portion 24 is provided in a part of the return bend 7, and an outlet of a constant flow passage width region 21 having a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage is provided between the outlet 12B of the first curved portion 12 of the return bend 7 and the inlet 13A of the second curved portion 13 of the return bend 7.
  • the constant flow passage width region 21 having a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage includes the diffuser 5, the first curved portion 12 of the return bend 7, and a part of the return bend 7.
  • the outlet position of the constant flow passage width region 21 having a narrower flow passage width than the impeller outlet on the upstream side of the stationary flow passage, where the flow passage width is constant at b3 is located downstream of the outlet 12B of the first curved portion 12 of the return bend 7, and therefore the flow passage width does not expand in the first curved portion 12 of the return bend.
  • the flow passage cross-sectional area does not expand in the radial direction or the axial direction.
  • an expanded flow passage region 22 is provided on the downstream side of the stationary flow passage from the exit of a constant flow passage width region 21, which has a narrower flow passage width than the impeller exit on the upstream side of the stationary flow passage provided between the exit 12B of the first curved portion 12 of the return bend 7 and the inlet 13A of the second curved portion 13 of the return bend 7, to the exit 10 of the return bend 7.
  • the flow passage cross-sectional area in the radial direction relative to the downstream flow direction of the working gas (fluid) is gradually or continuously expanded, so that a sudden increase in the flow passage cross-sectional area (a steep increase in the flow passage cross-sectional area) can be avoided and the working gas (fluid) can be decelerated while suppressing flow separation.
  • FIG. 8 also shows two components that form the flow passage wall surface of the stationary flow passage 14, the diaphragm 19A shown as a gray solid part in the figure, and the inner casing 19B shown as a hatched part in the figure.
  • the diaphragm 19A is formed integrally with the member surrounded by the diffuser 5, return bend 7, and return vane 8 of each stage, and the member surrounded by the return vane 8, the centrifugal impeller 1 of the next stage, and the diffuser 5.
  • the inner casing 19B is also formed as an integral part.
  • the installation part of the inclined flow passage wall surface newly provided on the radially outer side to form the expanded flow passage 22 is limited only to the inner peripheral side wall surface part of the inner casing 19B, so that the structure is simplified and the increase in processing time compared to the conventional structure can be suppressed.
  • a constant flow path width region can also be provided between the exit 25B of the expanded flow path section 25 in the return bend 7 and the entrance 13A of the second curved section 13 of the return bend 7, where both the inner diameter side and the outer diameter side of the meridian plane flow path shape become the axial flow path section 24.
  • the expansion rate of the flow passage width between the exit 12B of the first curved portion 12 of the return bend 7 and the entrance 13A of the second curved portion 13 of the return bend 7 may be set to be greater than the expansion rate of the flow passage width between the entrance 13A of the second curved portion 13 of the return bend 7 and the return bend exit 10. This is aimed at slowing down the working gas (fluid) as far upstream as possible while preventing rotating stall, and at reducing the amount of deceleration in the curved flow passage where separation is likely to occur when the flow passage is enlarged, and at least in the region including the axial flow passage 24.
  • the single-shaft multi-stage centrifugal compressor 20 described in this embodiment can also be used as a synthesis gas compressor in ammonia, methanol, and other synthesis plants.
  • the installation portion of the newly provided radially outer inclined flow passage wall surface for forming the expanded flow passage 22 is limited only to the inner peripheral wall surface portion of the inner casing 19B, thereby simplifying the structure and suppressing an increase in processing time compared to the conventional structure.
  • the wall friction is increased by increasing the flow channel wall roughness in the side wall portion 27 in the increased wall roughness region on the upstream side of the stationary flow channel, and the swirling component of the flow is reduced. Furthermore, downstream of the increased wall roughness region 26 on the upstream side of the stationary flow channel, an enlarged flow channel 22 is installed, which has a wider flow channel width than this region 26. This counteracts the effect of increased wall friction loss in the increased wall roughness region 26 on the upstream side of the stationary flow channel.
  • the arithmetic mean roughness (roughness) Ra of the channel wall surface on the machined surface is generally about 3.2 ⁇ m or more and 6.3 ⁇ m or less.
  • the channel wall roughness (roughness) Ra that can sufficiently reduce the swirling component of the flow in the channel wall roughness increased region 26 is preferably about 50 ⁇ m or more and 100 ⁇ m or less.
  • Such a channel wall roughness increased region can be realized by subjecting the channel wall surface to a blasting process such as shot blasting.
  • the single-shaft multi-stage centrifugal compressor 20 described in this embodiment can also be used as a synthesis gas compressor in ammonia, methanol, and other synthesis plants.
  • the present invention is not limited to the above-described embodiment, but includes various modifications.
  • the above-mentioned embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations described.
  • Diaphragm 19B Inner casing 20
  • Single-shaft multi-stage centrifugal compressor 21 Constant flow passage width region 22 narrower than the impeller outlet on the upstream side of the stationary flow passage... Expanded flow passage region 23 on the downstream side of the stationary flow passage... Side wall portion 24 of the constant flow passage width region narrower than the impeller outlet on the upstream side of the stationary flow passage... Axial flow passage portion 25 in the return bend... Expanded flow passage portion 25B in the return bend... Outlet 26 of the expanded flow passage portion in the return bend... Region of increased wall roughness on the upstream side of the stationary flow passage 27... Side wall portion b2 in the region of increased wall roughness on the upstream side of the stationary flow passage... Flow passage width b3 at the impeller outlet...

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Abstract

L'invention concerne une machine à fluide centrifuge à étages multiples qui peut atteindre à la fois une large plage de fonctionnement et une simplicité de conception d'aube de retour.　Une machine à fluide centrifuge à étages multiples 20 comprend : un diffuseur 5 dans lequel un passage d'écoulement fixe 14 est disposé au niveau d'un côté radialement externe d'une roue à aubes 1 ; un passage d'écoulement de retour 6 qui guide le fluide du diffuseur 5 à la roue à aubes 1 au niveau d'un étage arrière ; et une pluralité d'aubes de retour 8 qui sont disposées dans le passage d'écoulement de retour 6 et sont agencées à des intervalles le long d'une direction circonférentielle. Le passage d'écoulement de retour 6 a un coude de retour 7 qui guide, vers un côté radialement interne, un fluide qui a traversé le diffuseur 5. Le coude de retour 7 a une première partie incurvée 12 qui redirige le fluide depuis la direction radialement vers l'extérieur vers la même direction qu'un arbre rotatif 4 et une seconde partie incurvée 13 qui est positionnée sur le côté aval de la première partie incurvée 12 et redirige le fluide depuis la même direction que l'arbre rotatif 4 vers une direction radialement vers l'intérieur. Un bord avant de l'aube de retour 8 est positionné directement en aval de la sortie du coude de retour 7. Le diffuseur 5 et le coude de retour 7 sont sans aube et le passage d'écoulement fixe 14 présente, au niveau d'un côté amont, une région 21 ayant une largeur de passage d'écoulement constante dans laquelle la largeur de passage d'écoulement est plus étroite qu'une sortie de la roue à aubes 1 et présente, au niveau d'un côté aval, un passage d'écoulement agrandi 22 dans lequel la largeur de passage d'écoulement est augmentée pour être supérieure à la sortie de la roue à aubes 1.
PCT/JP2025/000685 2024-01-17 2025-01-10 Machine à fluide centrifuge à étages multiples Pending WO2025154678A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2024004937A JP2025110913A (ja) 2024-01-17 2024-01-17 多段遠心流体機械
JP2024-004937 2024-01-17

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WO2025154678A1 true WO2025154678A1 (fr) 2025-07-24

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PCT/JP2025/000685 Pending WO2025154678A1 (fr) 2024-01-17 2025-01-10 Machine à fluide centrifuge à étages multiples

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JP (1) JP2025110913A (fr)
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5954800A (ja) * 1982-09-22 1984-03-29 Hitachi Ltd 水平分割形ケ−シング
JPH08193600A (ja) * 1995-01-17 1996-07-30 Hitachi Ltd 遠心圧縮機
WO2014203379A1 (fr) * 2013-06-20 2014-12-24 三菱重工業株式会社 Compresseur centrifuge
US20170292536A1 (en) * 2014-09-30 2017-10-12 Siemens Aktiengesellschaft Return stage of a multi-stage turbocompressor or turboexpander having rough wall surfaces
WO2018155458A1 (fr) * 2017-02-22 2018-08-30 三菱重工コンプレッサ株式会社 Machine rotative centrifuge

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5954800A (ja) * 1982-09-22 1984-03-29 Hitachi Ltd 水平分割形ケ−シング
JPH08193600A (ja) * 1995-01-17 1996-07-30 Hitachi Ltd 遠心圧縮機
WO2014203379A1 (fr) * 2013-06-20 2014-12-24 三菱重工業株式会社 Compresseur centrifuge
US20170292536A1 (en) * 2014-09-30 2017-10-12 Siemens Aktiengesellschaft Return stage of a multi-stage turbocompressor or turboexpander having rough wall surfaces
WO2018155458A1 (fr) * 2017-02-22 2018-08-30 三菱重工コンプレッサ株式会社 Machine rotative centrifuge

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