US20160108920A1 - Centrifugal compressor - Google Patents

Centrifugal compressor Download PDF

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Publication number
US20160108920A1
US20160108920A1 US14/785,024 US201314785024A US2016108920A1 US 20160108920 A1 US20160108920 A1 US 20160108920A1 US 201314785024 A US201314785024 A US 201314785024A US 2016108920 A1 US2016108920 A1 US 2016108920A1
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United States
Prior art keywords
flow path
path width
diffuser section
side wall
section
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Abandoned
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US14/785,024
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English (en)
Inventor
Shuichi Yamashita
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Mitsubishi Heavy Industries Ltd
Mitsubishi Heavy Industries Compressor Corp
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Mitsubishi Heavy Industries Ltd
Mitsubishi Heavy Industries Compressor Corp
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Assigned to MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION, MITSUBISHI HEAVY INDUSTRIES, LTD. reassignment MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YAMASHITA, SHUICHI
Publication of US20160108920A1 publication Critical patent/US20160108920A1/en
Abandoned legal-status Critical Current

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    • 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
    • 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
    • F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/50—Inlet or outlet
    • F05D2250/52—Outlet

Definitions

  • the present invention relates to a centrifugal compressor.
  • a centrifugal compressor As a compressor used in a plant or the like, a centrifugal compressor is known. Several improvements are proposed in order to enable miniaturization of the centrifugal compressor, or operation at a small flow rate.
  • Patent Literature 1 discloses a centrifugal compressor in which a flow path width of one part of a diffuser is narrowed by use of a variable diaphragm mechanism in order to enable operation at a small flow rate.
  • Patent Literature 2 discloses a centrifugal compressor in which a flow path height of a diffuser flow path is gradually increases and a flow path width is enlarged in order to attain miniaturization and enlarge an operating range to a large flow rate side.
  • the present invention has been made in view of the above circumstances, and an object of the invention is to provide a centrifugal compressor in which a malfunction such as shaft vibration due to rotating stall and degradation of performance due to friction losses or the like are suppressed.
  • a centrifugal compressor includes: an impeller that is rotatable around an axis, and discharges fluid, which flows in an axial direction along the axis, in a direction inclined from the axial direction; a casing section that houses the impeller; and a diffuser section that circulates the fluid discharged from the impeller, wherein the impeller includes a hub and a shroud that are arranged along the axial direction side by side, and a plurality of blades that are arranged between the hub and the shroud, wherein a flow path width of the diffuser section at an inflow position where the fluid flows in the diffuser section is narrower than a flow path width of the impeller at a discharge position where the fluid discharges from the impeller, and wherein a flow path width enlarged section wider than the flow path width of the diffuser section at the inflow position is provided on a downstream side with respect to the inflow position of the diffuser section.
  • the centrifugal compressor according to the present invention includes: the impeller that discharges the fluid, which flows along the axial direction, in the direction inclined from the axial direction; the casing section that houses the impeller; and the diffuser section that circulates the fluid discharged from the impeller, wherein the impeller has the hub and the shroud that are arranged along the axial direction side by side, and the plurality of blades that are arranged between the hub and the shroud.
  • the flow path width of the diffuser section at the inflow position where the fluid flows in the diffuser section is narrower than the flow path width of the impeller at the discharge position where the fluid discharges from the impeller.
  • the flow velocity of the fluid at the inflow position where the fluid flows in the diffuser section is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the flow path width enlarged section wider than the flow path width of the diffuser section at the inflow position is provided on a downstream side with respect to the inflow position of the diffuser section.
  • the diffuser section is defined by a hub side wall provided on a side of the hub, and a shroud side wall provided on a side of the shroud
  • the hub side wall at the flow path width enlarged section is disposed in a direction in which the flow path width of the diffuser section enlarges with respect to the hub side wall at the inflow position
  • the shroud side wall at the flow path width enlarged section is disposed in a direction in which the flow path width of the diffuser section enlarges with respect to the shroud side wall at the inflow position.
  • both side walls at the flow path width enlarged section of the diffuser section are disposed in the direction in which the flow path width of the diffuser section enlarges, and it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section to the downstream side is the same.
  • the diffuser section is defined by a hub side wall provided on a side of the hub, and a shroud side wall provided on a side of the shroud, and the hub side wall at the flow path width enlarged section is disposed in a direction in which the flow path width of the diffuser section enlarges with respect to the hub side wall at the inflow position.
  • the hub side wall of the diffuser section at the flow path width enlarged section is disposed in the direction in which the flow path width of the diffuser section enlarges, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section to the downstream side is the same.
  • the hub side wall is disposed in the direction in which the flow path width of the diffuser section enlarges, and therefore it is possible to form the flow path in which the fluid is stably circulated, in a case where the discharge direction in which fluid discharges from the impeller is directed to a direction of the hub side wall with respect to a direction orthogonal to the axial direction.
  • the diffuser section is defined by a hub side wall provided on a side of the hub, and a shroud side wall provided on a side of the shroud, and the shroud side wall at the flow path width enlarged section is disposed in a direction in which the flow path width of the diffuser section enlarges with respect to the shroud side wall at the inflow position.
  • the shroud side wall of the diffuser section at the flow path width enlarged section is disposed in the direction in which the flow path width of the diffuser section enlarges, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section to the downstream side is the same.
  • a shape of the hub side wall may be a tapered shape in which the flow path width gradually enlarges along a circulating direction of the fluid at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section
  • a shape of the shroud side wall may be a tapered shape in which the flow path width gradually enlarges along the circulating direction of the fluid at the intermediate position of the diffuser section.
  • a shape of the hub side wall may be a tapered shape in which the flow path width gradually enlarges along a circulating direction of the fluid at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section.
  • a shape of the shroud side wall may be a tapered shape in which the flow path width gradually enlarges along a circulating direction of the fluid at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section.
  • a shape of the hub side wall may be a stepped shape in which the flow path width enlarges along a circulating direction of the fluid stepwise at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section
  • a shape of the shroud side wall may be a stepped shape in which the flow path width enlarges along the circulating direction of the fluid stepwise at the intermediate position of the diffuser section.
  • the flow path connecting the inflow position and the downstream side can be formed at the intermediate position of the diffuser section by a relatively easy machining process.
  • a shape of the hub side wall may be a stepped shape in which the flow path width enlarges along a circulating direction of the fluid stepwise at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section.
  • the flow path connecting the inflow position and the downstream side can be formed at the intermediate position of the diffuser section by a relatively easy machining process.
  • a shape of the shroud side wall may be a stepped shape in which the flow path width enlarges along a circulating direction of the fluid stepwise at an intermediate position between the inflow position of the diffuser section and the flow path width enlarged section.
  • the flow path connecting the inflow position and the downstream side can be formed at the intermediate position of the diffuser section by a relatively easy machining process.
  • a ratio of the flow path width of the diffuser section at the inflow position to the flow path width of the impeller at the discharge position is not less than 0.5 and less than 0.8.
  • the flow path width of the diffuser section at the inflow position is made to be a sufficiently narrow width, and the flow velocity of the fluid at the inflow position where the fluid flows in the diffuser section is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • a ratio of a flow path width of the diffuser section at the flow path width enlarged section to the flow path width of the impeller at the discharge position is not less than 0.8 and not more than 1.0.
  • the flow path width of the diffuser section at the flow path width enlarged section is made to be a sufficiently wide width, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section to the downstream side is the same.
  • the impeller discharges the fluid, which flows along the axial direction, in a direction orthogonal to the axial direction.
  • a flow rate coefficient is not less than 0.01 and not more than 0.05.
  • the present invention it is possible to provide a centrifugal compressor in which a malfunction such as shaft vibration due to rotating stall is suppressed, and degradation of performance due to friction losses or the like is suppressed.
  • FIG. 1 is a longitudinal sectional view of a centrifugal compressor of a first embodiment.
  • FIG. 2 is a front view of the centrifugal compressor of the first embodiment.
  • FIG. 3 is a longitudinal sectional view of a centrifugal compressor of a second embodiment.
  • FIG. 4 is a longitudinal sectional view of a centrifugal compressor of a third embodiment.
  • FIG. 5 is a longitudinal sectional view of a centrifugal compressor of a fourth embodiment.
  • FIG. 6 is a longitudinal sectional view of a centrifugal compressor of a fifth embodiment.
  • FIG. 1 is a longitudinal sectional view of the centrifugal compressor 10 of the first embodiment.
  • FIG. 2 is a front view of the centrifugal compressor 10 of the first embodiment.
  • the centrifugal compressor 10 illustrated in FIG. 1 includes an impeller 13 rotatable around an axis A, a casing section 11 housing the impeller 13 , a diffuser section 15 for circulating fluid discharged from the impeller 13 , and a volute section 16 provided downstream of the diffuser section 15 .
  • FIG. 2 is a front view when viewing a position where fluid flows in the impeller 13 along the axial direction of axis A.
  • the impeller 13 , the diffuser section 15 , the casing section 11 , and the volute section 16 are partially omitted.
  • the centrifugal compressor 10 of the first embodiment is a centrifugal compressor whose flow rate coefficient is a relatively small flow rate coefficient, namely not less than 0.01 and not more than 0.05.
  • the impeller 13 is connected to a driving device such as a motor and a turbine (not illustrated) through a rotary shaft (not illustrated) along the axis A, and is rotatable around the axis A.
  • the impeller 13 has a hub 1 and a shroud 2 arranged along the axial direction of axis A, and a plurality of blades 3 arranged between the hub 1 and the shroud 2 . Although only one blade 3 is illustrated in FIG. 1 , a plurality of the blades 3 are arranged at equal intervals in a circumferential direction with the axis A as the center, between the hub 1 and the shroud 2 ( FIG. 2 ).
  • the impeller 13 is provided with a space defined by an inner wall la of the hub 1 and an inner wall 2 a of the shroud 2 , and the space is partitioned into a plurality of spaces by the plurality of blades 3 . Then, the impeller 13 applies radial centrifugal force to fluid flowing along the axial direction (direction illustrated by the arrow in FIG. 1 ), discharges the fluid in a direction orthogonal to the axial direction (inclined direction; radial direction of the impeller 13 ), and allows the fluid to flow in the diffuser section 15 .
  • the diffuser section 15 is a fluid flow path defined by a hub side wall 15 a provided on the hub 1 side and a shroud side wall 15 b provided on the shroud 2 side. As illustrated in FIG. 2 , the diffuser section 15 is provided so as to surround a discharge position provided on a whole circumference of the impeller 13 . In the diffuser section 15 , the flow velocity of the fluid discharged from the discharge position of the impeller 13 is reduced, so that kinetic energy (dynamic pressure) applied to the fluid is converted into pressure energy (static pressure).
  • the fluid is compressed, and flows in a volute section (volute chamber) 16 communicated with diffuser section 15 .
  • the compressed fluid that flows in the volute section 16 is discharged to a discharge pipe (not illustrated) through a discharge port (not illustrated).
  • the driving device such as the motor and the turbine (not illustrated) rotates the impeller 13 around the axis A.
  • the impeller 13 rotates, so that fluid taken from a suction port (not illustrated) is introduced into the casing section 11 .
  • centrifugal force in the direction orthogonal to the axis A radial direction
  • the fluid, to which the centrifugal force is applied is discharged from the impeller 13 , and flows in the diffuser section 15 .
  • the flow velocity of the fluid that flows in the diffuser section 15 reduces, and the fluid becomes compressed fluid to be discharged to the volute section 16 .
  • the compressed fluid that flows in the volute section 16 is discharged to the discharge pipe (not illustrated) through the discharge port (not illustrated).
  • a flow path width W 2 of the diffuser section 15 at an inflow position where fluid flows in the diffuser section 15 is narrower than a flow path width W 1 of the impeller 13 at a discharge position where the fluid is discharged from the impeller 13 .
  • a flow path width enlarged section 15 c in which the flow path width of the diffuser section 15 is enlarged is provided on the downstream side of the inflow position where the fluid flows in the diffuser section 15 , in order to suppress the losses due to the friction.
  • the flow path width W 1 expresses a length in a direction along the axis A (axial direction).
  • the flow path width W 1 is equal to a distance in the axial direction between the inner wall 1 a of the hub 1 and the inner wall 2 a of the shroud 2 at the discharge position where the fluid is discharged from the impeller 13 .
  • the flow path width W 2 expresses a length in the direction along the axis A.
  • the flow path width W 2 is equal to a distance in the axial direction between the hub side wall 15 a and the shroud side wall 15 b at the inflow position where the fluid flows in the diffuser section 15 .
  • the flow path width of the diffuser section 15 (distance in the axial direction between the hub side wall 15 a and the shroud side wall 15 b ) in a range in a circulating direction of the fluid (direction orthogonal to the axial direction) from the inflow position where the fluid flows in the diffuser section 15 to L 1 is constant, namely the flow path width W 2 . Then, at a position (intermediate position) where the distance from the inflow position is between L 1 and L 2 , the hub side wall 15 a that defines the diffuser section 15 has a tapered shape in which the flow path width gradually enlarges along the circulating direction of the fluid.
  • the shroud side wall 15 b that defines the diffuser section 15 also has a tapered shape in which the flow path width gradually enlarges along the circulating direction of the fluid.
  • the hub side wall 15 a at a position where the distance from the inflow position where the fluid flows in the diffuser section 15 is between L 2 and L 3 is disposed in a direction in which the flow path width of the diffuser section 15 enlarges with respect to the hub side wall 15 a at the inflow position where the fluid flows in the diffuser section 15 .
  • the shroud side wall 15 b is disposed in a direction in which the flow path width of the diffuser section 15 enlarges with respect to the shroud side wall 15 b at the inflow position where the fluid flows in the diffuser section 15 .
  • the flow path width of the diffuser section 15 is constant, namely a flow path width W 3 .
  • the flow path width enlarged section 15 c that is wider than the flow path width of the diffuser section 15 at the inflow position of the diffuser section 15 is provided on the downstream side in the circulating direction of the fluid with respect to the inflow position where the fluid flows in the diffuser section 15 .
  • the shape of the hub side wall 15 a and the shape of the shroud side wall 15 b are desirably horizontally symmetrical with respect to the center axis of the flow path.
  • a ratio of the flow path width W 2 of the diffuser section 15 at the inflow position to the flow path width W 1 of the impeller 13 at the discharge position is not less than 0.5 and less than 0.8. Additionally, a ratio of the flow path width W 3 of the diffuser section 15 at the flow path width enlarged section 15 c to the flow path width W 1 of the impeller 13 at the discharge position is not less than 0.8 and not more than 1.0. However, as described above, the respective ratios are selected such that the flow path width W 3 of the diffuser section 15 at the flow path width enlarged section 15 c is wider than the flow path width W 2 of the diffuser section 15 at the inflow position.
  • the centrifugal compressor 10 of the first embodiment includes the impeller 13 that discharges fluid, which flows along the axial direction, in the inclined direction from the axial direction (radial direction orthogonal to the axial direction), the casing section 11 that houses the impeller 13 , and the diffuser section 15 that circulates the fluid discharged from the impeller 13 , wherein the impeller 13 has the hub 1 and the shroud 2 arranged along the axial direction side by side, and the plurality of blades 3 arranged between the hub 1 and the shroud 2 .
  • the flow path width W 2 of the diffuser section 15 at the inflow position where the fluid flows in the diffuser section 15 is narrower than the flow path width W 1 of the impeller 13 at the discharge position where the fluid is discharged from the impeller 13 .
  • the flow velocity of the fluid at the inflow position where the fluid flows in the diffuser section 15 is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the flow path width enlarged section 15 c having the flow path width W 3 wider than the flow path width of the diffuser section 15 at the inflow position of the diffuser section 15 is provided downstream with respect to the inflow position of the diffuser section 15 .
  • it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid circulating in the diffuser section 15 compared to a case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • the diffuser section 15 is defined by the hub side wall 15 a provided on the hub 1 side, and the shroud side wall 15 b provided on the shroud 2 side. Then, the hub side wall 15 a at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the hub side wall 15 a at the inflow position. Additionally, the shroud side wall 15 b at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the shroud side wall 15 b at the inflow position.
  • the both side walls at the flow path width enlarged section 15 c of the diffuser section 15 are disposed in the direction in which the flow path width of the diffuser section 15 enlarges, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to the case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • the shape of the hub side wall 15 a is the tapered shape in which the flow path width gradually enlarges along the circulating direction of the fluid at the intermediate position between the inflow position of the diffuser section 15 and the flow path width enlarged section 15 c
  • the shape of the shroud side wall 15 b is the tapered shape in which the flow path width gradually enlarges along the circulating direction of the fluid at the intermediate position of the diffuser section 15 .
  • the ratio of the flow path width W 2 of the diffuser section 15 at the inflow position to the flow path width W 1 of the impeller 13 at the discharge position is not less than 0.5 and less than 0.8.
  • the flow path width W 2 relative to the flow path width W 1 is made to be a sufficiently narrow width, and the flow velocity of the fluid at the inflow position where the fluid flows in the diffuser section 15 is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the ratio of the flow path width W 3 of the diffuser section 15 at the flow path width enlarged section 15 c to the flow path width W 1 of the impeller 13 at the discharge position is not less than 0.8 and not more than 1.0.
  • the flow path width W 3 relative to the flow path width W 1 is made to be a sufficiently wide width, and it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to the case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • FIG. 3 is a longitudinal sectional view of the centrifugal compressor 10 of the second embodiment.
  • the both side walls (the hub side wall 15 a and the shroud side wall 15 b ) of the diffuser section 15 at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges.
  • one side wall (hub side wall 15 a ) of a diffuser section 15 at a flow path width enlarged section 15 c is disposed in a direction in which a flow path width of the diffuser section 15 enlarges.
  • the second embodiment is a modification of the first embodiment.
  • Configurations other than the shape of the hub side wall 15 a which defines the diffuser section 15 are similar to those of the first embodiment, and therefore the description of the configurations will be omitted.
  • the hub side wall 15 a at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the hub side wall 15 a at an inflow position.
  • the shroud side wall 15 b at the flow path width enlarged section 15 c and the shroud side wall 15 b at the inflow position are disposed such that the positions in the axial direction are the same.
  • the centrifugal compressor 10 illustrated in FIG. 3 discharges fluid, which flows in an impeller 13 , in a direction orthogonal to the axial direction
  • a modification in which the centrifugal compressor discharges fluid in a direction inclined to the hub side wall 15 a with respect to the direction orthogonal to the axial direction is applicable.
  • the fluid that flows in the diffuser section 15 includes a velocity component in a direction in which the fluid vertically abuts on the hub side wall 15 a. Accordingly, a loss due to friction is more easily generated at the hub side wall 15 a than the shroud side wall 15 b, and therefore suppression of a friction loss generated at the hub side wall 15 a is desirable.
  • the hub side wall 15 a is disposed in the direction in which the flow path width of the diffuser section 15 enlarges, and therefore it is possible to form the flow path in which the fluid is stably circulated, and a friction loss caused by the hub side wall 15 a is suppressed, in a case where a discharge direction in which fluid discharged from the impeller 13 is directed (inclined) to the direction of the hub side wall 15 a with respect to the direction orthogonal to the axial direction.
  • a compressor of a type of discharge in a direction inclined to the hub side wall 15 a with respect to the direction orthogonal to the axial direction of the impeller 13 is called a mixed flow compressor.
  • the compressor is not called the mixed flow compressor, but called a centrifugal compressor which means a compressor that converts fluid flowing in the axial direction into fluid including a velocity component in a direction orthogonal to an axis A (centrifugal direction).
  • a flow path width W 2 of the diffuser section 15 at the inflow position where the fluid flows in the diffuser section 15 is narrower than a flow path width W 1 of the impeller 13 at a discharge position where the fluid is discharged from the impeller 13 .
  • a flow velocity of fluid at the inflow position where the fluid flows in the diffuser section 15 is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the hub side wall 15 a at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the hub side wall 15 a at the inflow position.
  • the hub side wall 15 a of the diffuser section 15 at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • the shape of the hub side wall 15 a is a tapered shape in which the flow path width gradually enlarges along a circulating direction of the fluid at an intermediate position between the inflow position of the diffuser section 15 and the flow path width enlarged section 15 c.
  • the flow path width gradually enlarges along a circulating direction of the fluid at an intermediate position between the inflow position of the diffuser section 15 and the flow path width enlarged section 15 c.
  • FIG. 4 is a longitudinal sectional view of the centrifugal compressor 10 of the third embodiment.
  • the both side walls (the hub side wall 15 a and the shroud side wall 15 b ) of the diffuser section 15 at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges.
  • one side wall (shroud side wall 15 b ) of a diffuser section 15 at a flow path width enlarged section 15 c is disposed in a direction in which a flow path width of the diffuser section 15 enlarges.
  • the third embodiment is a modification of the first embodiment. Configurations other than the shape of the shroud side wall 15 b which defines the diffuser section 15 are similar to those of the first embodiment, and therefore the description of the configurations will be omitted.
  • the shroud side wall 15 b at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the shroud side wall 15 b at an inflow position.
  • the hub side wall 15 a at the flow path width enlarged section 15 c and the hub side wall 15 a at the inflow position are disposed such that the positions in the axial direction are the same.
  • a flow path width W 2 of the diffuser section 15 at the inflow position where the fluid flows in the diffuser section 15 is narrower than a flow path width W 1 of the impeller 13 at a discharge position where the fluid is discharged from the impeller 13 .
  • a flow velocity of fluid at the inflow position where the fluid flows in the diffuser section 15 is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the shroud side wall 15 b at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges with respect to the shroud side wall 15 b at the inflow position.
  • the shroud side wall 15 b of the diffuser section 15 at the flow path width enlarged section 15 c is disposed in the direction in which the flow path width of the diffuser section 15 enlarges, so that it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of the fluid, compared to a case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • the shape of the shroud side wall 15 b is the tapered shape in which the flow path width gradually enlarges along a circulating direction of the fluid at the intermediate position of the diffuser section 15 .
  • FIG. 5 is a longitudinal sectional view of the centrifugal compressor 10 of the fourth embodiment.
  • both the hub side wall 15 a and the shroud side wall 15 b have tapered shapes in which the flow path width gradually enlarges along the circulating direction of fluid.
  • a flow path width of a diffuser section 15 (distance in the axial direction between a hub side wall 15 a and a shroud side wall 15 b ) in a range in the circulating direction of the fluid (direction orthogonal to the axial direction) from an inflow position where the fluid flows in the diffuser section 15 to L 4 is constant, namely a flow path width W 2 . Then, at a position where the distance from the inflow position is between L 4 and L 3 , the flow path width of the diffuser section 15 is constant, namely a flow path width W 3 .
  • the diffuser section 15 may be formed in a stepped shape of two steps, three steps, or more steps, and the flow path width of the diffuser section may be gradually enlarge.
  • both the hub side wall 15 a and the shroud side wall 15 b are provided with stepped shapes.
  • the stepped shape may be provided in any one of the hub side wall 15 a and the shroud side wall 15 b, and the stepped shape may not be provided in the other wall.
  • the hub side wall 15 a at the flow path width enlarged section 15 c, and the hub side wall 15 a at the inflow position are disposed such that the positions in the axial direction are the same.
  • the shroud side wall 15 b at the flow path width enlarged section 15 c, and the shroud side wall 15 b at the inflow position are disposed such that the positions in the axial direction are the same.
  • a flow path width W 2 of the diffuser section 15 at the inflow position where the fluid flows in the diffuser section 15 is narrower than a flow path width W 1 of an impeller 13 at a discharge position where the fluid is discharged from the impeller 13 .
  • a flow velocity of fluid at the inflow position where the fluid flows in the diffuser section 15 is sufficiently increased, and occurrence of rotating stall is suppressed, so that it is possible to suppress a malfunction such as shaft vibration due to rotating stall.
  • the flow path width enlarged section 15 c having the flow path width W 3 which is wider than the flow path width W 2 of the diffuser section 15 at the inflow position of the diffuser section 15 , is provided on the downstream side with respect to the inflow position of the diffuser section 15 .
  • it is possible to suppress degradation of performance due to, for example, friction losses caused by increase in the flow velocity of fluid circulating in the diffuser section 15 compared to a case where the flow path width from the inflow position of the diffuser section 15 to the downstream side is the same flow path width, namely the flow path width W 2 .
  • the shape of the hub side wall 15 a is the stepped shape in which the flow path width enlarges along the circulating direction of the fluid stepwise at the intermediate position between the inflow position of the diffuser section 15 and the flow path width enlarged section 15 c
  • the shape of the shroud side wall 15 b is the stepped shape in which the flow path width gradually enlarges along the circulating direction of the fluid at the intermediate position of the diffuser section 15 .
  • FIG. 6 is a longitudinal sectional view of the centrifugal compressor 10 of the fifth embodiment.
  • the centrifugal compressor 10 of the fifth embodiment is a multistage centrifugal compressor in which fluid compressed by an impeller 13 and a diffuser section 15 at the first stage flows in an impeller 13 and a diffuser section 15 at a next stage.
  • the fifth embodiment is a modification of the first embodiment. Configurations are similar to those of the first embodiment except that a return bend 17 and a return vane 18 are provided in place of the volute section 16 , and therefore the description of the configurations will be omitted.
  • compressed fluid that flows in the flow path width enlarged section 15 c of the diffuser section 15 flows in the volute section 16 provided downstream of the flow path width enlarged section 15 c.
  • compressed fluid that flows in a flow path width enlarged section 15 c of the diffuser section 15 flows in the return bend 17 provided downstream of the flow path width enlarged section 15 c.
  • the compressed fluid that flows in the return bend 17 is guided to the impeller 13 at the next stage (second stage) via the return vane 18 .
  • the fluid guided to the impeller 13 at the second stage is discharged to the diffuser section 15 at the second stage.
  • the fluid further compressed in the diffuser section 15 at the second stage is guided to a volute section 16 similar to the volute section illustrated in FIG. 1 of the first embodiment.
  • fluid guided to an impeller 13 at a second stage is discharged to a diffuser section 15 at a second stage.
  • the fluid further compressed in the diffuser section 15 at the second stage flows in a return bend 17 at the second stage.
  • the compressed fluid that flows in the return bend 17 at the second stage is guided to an impeller 13 at a next state (third stage) via the return vane 18 .
  • the fluid guided to the impeller 13 at the third stage is discharged to a diffuser section 15 at the third stage.
  • the fluid further compressed in the diffuser section 15 at the third stage is guided to a volute section 16 similar to the volute section illustrated in FIG. 1 of the first embodiment.
  • the two-stage or the three-stage centrifugal compressor 10 is employed as the centrifugal compressor 10 , so that it is possible to further increase a compression ratio of fluid. Additionally, an effect similar to the effect of the first embodiment can be exerted by the shapes of the impeller 13 and the diffuser section 15 at each stage.
  • the shape of the diffuser section 15 at each stage not only the shape described in the first embodiment, but also any shape described in the second embodiment to the fourth embodiment can be employed.
  • the two-stage and the three-stage centrifugal compressor 10 are described. However, a modification of a four or more stage centrifugal compressor 10 may be employed.
US14/785,024 2013-06-20 2013-06-20 Centrifugal compressor Abandoned US20160108920A1 (en)

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US20190128270A1 (en) * 2017-10-26 2019-05-02 Hanwha Powersystems Co., Ltd Closed impeller with self-recirculation casing treatment
DE102017127758A1 (de) * 2017-11-24 2019-05-29 Man Diesel & Turbo Se Radialverdichter und Turbolader
US20190271328A1 (en) * 2018-03-02 2019-09-05 Ingersoll-Rand Company Centrifugal compressor system and diffuser
US10544800B2 (en) * 2015-04-14 2020-01-28 Mitsubishi Heavy Industries Thermal Systems, Ltd. Inlet guide vane and centrifugal compressor
US11859543B2 (en) 2019-06-03 2024-01-02 Pratt & Whitney Canada Corp. Diffuser pipe with exit flare

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WO2017109949A1 (ja) * 2015-12-25 2017-06-29 三菱重工業株式会社 遠心圧縮機及びターボチャージャ
CN109707665B (zh) * 2017-10-26 2022-04-29 韩华压缩机株式会社 具有自行再循环机匣处理的闭式叶轮

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US9970455B2 (en) * 2015-02-05 2018-05-15 Hanwha Power Systems Co., Ltd. Compressor
US20160230775A1 (en) * 2015-02-05 2016-08-11 Hanwha Techwin Co., Ltd. Compressor
US10544800B2 (en) * 2015-04-14 2020-01-28 Mitsubishi Heavy Industries Thermal Systems, Ltd. Inlet guide vane and centrifugal compressor
US20190128270A1 (en) * 2017-10-26 2019-05-02 Hanwha Powersystems Co., Ltd Closed impeller with self-recirculation casing treatment
KR20190046601A (ko) * 2017-10-26 2019-05-07 한화파워시스템 주식회사 자가 재순환 케이싱을 구비한 밀폐형 임펠러
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US10935035B2 (en) * 2017-10-26 2021-03-02 Hanwha Power Systems Co., Ltd Closed impeller with self-recirculation casing treatment
CN109931295A (zh) * 2017-11-24 2019-06-25 曼恩能源方案有限公司 径向压缩机和涡轮增压器
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DE102017127758A1 (de) * 2017-11-24 2019-05-29 Man Diesel & Turbo Se Radialverdichter und Turbolader
US20190271328A1 (en) * 2018-03-02 2019-09-05 Ingersoll-Rand Company Centrifugal compressor system and diffuser
US10851801B2 (en) * 2018-03-02 2020-12-01 Ingersoll-Rand Industrial U.S., Inc. Centrifugal compressor system and diffuser
US11859543B2 (en) 2019-06-03 2024-01-02 Pratt & Whitney Canada Corp. Diffuser pipe with exit flare

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CN105121864A (zh) 2015-12-02
CN105121864B (zh) 2017-06-09
EP3012461A1 (en) 2016-04-27
EP3012461A4 (en) 2017-02-08

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