EP2955387A1 - Centrifugal compressor - Google Patents
Centrifugal compressor Download PDFInfo
- Publication number
- EP2955387A1 EP2955387A1 EP13874463.6A EP13874463A EP2955387A1 EP 2955387 A1 EP2955387 A1 EP 2955387A1 EP 13874463 A EP13874463 A EP 13874463A EP 2955387 A1 EP2955387 A1 EP 2955387A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- flow channel
- fluid
- impeller
- outlet
- opening section
- 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.)
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Classifications
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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
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/68—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers
- F04D29/681—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers especially adapted for elastic fluid pumps
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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
- 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
- F04D17/122—Multi-stage pumps the individual rotor discs being, one for each stage, on a common shaft and axially spaced, e.g. conventional centrifugal multi- stage compressors
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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
- F04D29/00—Details, component parts, or accessories
- F04D29/08—Sealings
- F04D29/10—Shaft sealings
- F04D29/102—Shaft sealings especially adapted for elastic fluid 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
- F04D29/26—Rotors specially for elastic fluids
- F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
- F04D29/284—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for compressors
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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
- 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
- F04D29/4206—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for elastic fluid pumps
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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
- 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
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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
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/68—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers
- F04D29/681—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers especially adapted for elastic fluid pumps
- F04D29/684—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers especially adapted for elastic fluid pumps by fluid injection
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- 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 configured to compress a gas using a centrifugal force.
- a centrifugal compressor is configured to allow a gas to pass through a rotating impeller in a radial direction and compress the gas using a centrifugal force generated thereupon.
- a multi-stage type centrifugal compressor including impellers in an axial direction in a plurality of stages and configured to compress a gas in a stepped manner is known.
- the impeller In the centrifugal compressor, the impeller is rotatably supported on a rotary shaft in a casing, and as the impeller is rotated, a fluid such as an air, a gas, or the like, is suctioned from a suction port of the casing and a centrifugal force is applied thereto. Then, kinetic energy is converted into pressure energy by a diffuser and a scroll section to be delivered from a discharge port of the casing.
- a fluid such as an air, a gas, or the like
- a diffuser width is set to be smaller than in the related art, or a circulation flow channel that connects an impeller back surface and a diffuser inlet is installed (for example, see Patent Literature 1 and Patent Literature 2).
- a structure in which the rotating stall cannot be easily generated is provided by increasing a flow velocity in a diffuser inlet and further reducing the flow angle of the flow in a radial direction.
- a leakage from a seal (for example, a labyrinth seal) installed between a rotary shaft and a hub casing may be increased.
- An object of the present invention is to provide a centrifugal compressor capable of more securely limiting the occurrence of rotating stall by increasing the flow velocity of a fluid that flows through an outlet flow channel.
- a centrifugal compressor includes: an impeller configured to discharge a fluid introduced toward one side in an axial direction from an outlet directed to the outside in a radial direction through rotation thereof; and a casing installed to surround the impeller and having an outlet flow channel through which a fluid sent from the outlet of the impeller flows downstream thereby increasing the pressure of the fluid therein further downstream in the flow direction, wherein a circulation flow channel having a first opening section connected to the outlet flow channel and a second opening section connected to an upstream side of the first opening section in the outlet flow channel is formed.
- the second opening section may be oriented toward the downstream side of the outlet flow channel.
- the outlet flow channel may include: a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy, and a scroll connected to an outlet of the diffuser and configured to eject the fluid to the outside, and the first opening section may be formed at the scroll.
- the outlet flow channel may include a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy, and the first opening section may be formed at an outlet side of the diffuser.
- a centrifugal compressor 1 of the embodiment is generally constituted by a rotary shaft 2 rotatable about an axis O, an impeller 3 attached to the rotary shaft 2 and configured to compress a fluid G such as an air or the like using a centrifugal force, and a casing 5 configured to rotatably support the rotary shaft 2 and having a flow channel 4 through which the fluid G flows from an upstream side toward a downstream side.
- the casing 5 is configured to form a substantially columnar contour, and the rotary shaft is disposed to pass through a center of the casing 5.
- journal bearings 7 are installed at both ends of the rotary shaft 2 in the axial direction, and a thrust bearing 8 is installed at one end thereof.
- the journal bearings 7 and the thrust bearing 8 rotatably support the rotary shaft 2. That is, the rotary shaft 2 is supported by the casing 5 via the journal bearings 7 and the thrust bearing 8.
- a suction port 9 configured to introduce the fluid G from the outside is formed at one end side of the casing 5 in the axial direction and a discharge port 10 configured to discharge the fluid G to the outside is formed at the other end side.
- an internal space 11 in communication with the suction port 9 and the discharge port 10 and having a diameter which is repeatedly increased and a decreased is provided.
- the internal space 11 functions as a space for accommodating the impeller 3 and also functions as the above-mentioned flow channel 4. That is, the suction port 9 and the discharge port 10 are in communication with each other via the impeller 3 and the flow channel 4.
- the casing 5 is constituted by a shroud casing 5a and a hub casing 5b, and the internal space 11 is defined by the shroud casing 5a and the hub casing 5b.
- each of the impellers 3 is constituted by a substantially disk-shaped hub 13 having a diameter gradually increased toward the discharge port 10, a plurality of blades 14 radially attached to the hub 13 and disposed in a circumferential direction in parallel, and a shroud 15 attached to cover front end sides of the plurality of blades 14 in the circumferential direction.
- the flow channel 4 is formed to advance in the axial direction and connect the impellers 3 while meandering in the radial direction of the rotary shaft 2 such that the fluid G is compressed by the plurality of impellers 3 in the stepped manner.
- the flow channel 4 is generally constituted by a suction passage 17, a compression passage 18, a diffuser passage 19, and a return passage 20.
- the diffuser passage 19 is a passage configured to convert kinetic energy applied to the fluid by the impellers 3 into pressure energy.
- the suction passage 17 is a passage configured to convert the direction of the fluid G into the axial direction of the rotary shaft 2 immediately before the impeller 3 after the fluid G flows from the outside in the radial direction toward the inside in the radial direction.
- the suction passage 17 is constituted by a straight passage 21 having a linear shape through which the fluid G flows from the outside in the radial direction toward the inside in the radial direction, and a corner passage 22 having a curved shape and configured to convert the flow direction of the fluid G flowing from the straight passage 21 from the inside in the radial direction into the axial direction to direct the fluid G toward the impeller 3.
- a plurality of return vanes 23 radially disposed about the axis O and configured to divide the straight passage 21 in the circumferential direction of the rotary shaft 2 are installed at the straight passage 21 disposed between the two impellers 3.
- the compression passage 18 is a passage configured to compress the fluid G conveyed from the suction passage 17, in the impeller 3, and is defined by being surrounded by a blade attachment surface of the hub 13 and an inner wall surface of the shroud 15.
- the diffuser passage 19 has an inside in the radial direction in communication with the compression passage 18, and functions to allow the fluid G compressed by the impeller 3 to flow outward in the radial direction. Further, while the outside in the radial direction of the diffuser passage 19 is in communication with the return passage 20, the diffuser passage 19 connected to the outside in the radial direction of the impeller 3 disposed at the most downstream side of the flow channel 4 (in Fig. 1 , the sixth impeller 3) is in communication with an ejection scroll 12, which will be described below.
- the return passage 20 is formed with a substantially U-shaped cross section, an upstream end side of the return passage 20 is in communication with the diffuser passage 19, and a downstream end side is in communication with the straight passage 21 of the suction passage 17.
- the return passage 20 reverses the flow direction of the fluid G flowing to the outside in the radial direction through the diffuser passage 19 toward the inside in the radial direction due to the impeller 3 (the impeller 3 of the upstream side), and delivers the fluid G to the straight passage 21.
- the ejection scroll 12 configured to eject the fluid from the ejection port is formed in the casing 5.
- the ejection scroll 12 has a scroll flow channel 25 formed to surround the entire circumference of the outlet of the diffuser passage 19 disposed at an outer circumferential section of the impeller 3 of the final stage.
- the scroll flow channel 25 is formed to surround the entire circumference of the outlet of the diffuser passage 19 disposed at the outer circumferential section of the impeller 3 of the final stage, and is formed to gradually and continuously enlarge a cross-sectional area thereof in a rotational direction of the impeller 3.
- the diffuser passage 19 and the ejection scroll 12 function as an outlet flow channel 6 configured to increase a pressure of the fluid as the fluid is directed toward the downstream side while the fluid provided from the outlet of the impeller 3 flows therethrough.
- a circulation flow channel 26 connecting the bottom surface of the scroll flow channel 25 of the ejection scroll 12 and the diffuser passage 19 is formed.
- the circulation flow channel 26 is the flow channel 4 having a second opening section 28 formed in the vicinity of an inlet of the diffuser passage 19, and a first opening section 27 formed at the bottom surface of the scroll flow channel 25.
- the second opening section 28 is formed to be directed toward the downstream side of the diffuser passage 19. That is, the second opening section 28 oriented such that the compressed air introduced from the first opening section 27 and ejected from the second opening section 28 is ejected toward the outlet of the diffuser passage 19.
- the fluid G is compressed by the impellers 3 in the middle of flowing through the flow channel 4 in the above-mentioned sequence. That is, in the centrifugal compressor 1, the fluid G is compressed by the plurality of impellers 3 in the stepped manner, and thus, a large compression ratio can be easily obtained.
- the circulation flow channel 26 is configured to capture some of the compressed fluid from the first opening section 27 and eject the compressed fluid from the second opening section 28 such that some of the compressed fluid is circulated between the diffuser passage 19 and the ejection scroll 12.
- the compressed air is introduced from the first opening section 27 of the scroll flow channel 25 to be ejected from the second opening section 28 of the diffuser passage 19 via the circulation flow channel 26. That is, the compressed air is circulated to increase a flow velocity of the fluid flowing through the diffuser passage 19 with the compressed fluid. Accordingly, occurrences of rotating stall can be more securely limited.
- the second opening section 28 is formed to be oriented toward the downstream side of the diffuser passage 19, since the compressed fluid introduced from the second opening section 28 is ejected toward the downstream side of the diffuser passage 19, the flow velocity of the fluid flowing through the diffuser passage 19 can be further increased.
- a formed place of the first opening section 27 may be a downstream side of the second opening section 28 on the outlet flow channel constituted by the diffuser passage 19 and the ejection scroll 12.
- a configuration in which the first opening section 27 is formed at the outlet side of the diffuser passage 19 may be provided.
- the circulation flow channel 26 may be branched off from a conventional line to eject the fluid to the diffuser passage 19 without necessity of newly forming the entire circulation flow channel.
- the second opening section 28 is configured to be oriented toward a slipstream side of the diffuser passage 19, it is not limited thereto as long the flow velocity of the compressed fluid flowing through the diffuser passage 19 should not decreased.
- the fluid may be injected in a direction perpendicular to the extending direction of the diffuser passage 19.
- occurrences of rotating stall can be more securely limited by circulating the fluid such that the fluid introduced from the second opening section of the outlet flow channel increases the flow velocity of the fluid flowing through the outlet flow channel.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Description
- The present invention relates to a centrifugal compressor configured to compress a gas using a centrifugal force.
- Priority is claimed on Japanese Patent Application No.
2013-020704, filed February 5, 2013 - As is well known, a centrifugal compressor is configured to allow a gas to pass through a rotating impeller in a radial direction and compress the gas using a centrifugal force generated thereupon. In such a centrifugal compressor, a multi-stage type centrifugal compressor including impellers in an axial direction in a plurality of stages and configured to compress a gas in a stepped manner is known.
- In the centrifugal compressor, the impeller is rotatably supported on a rotary shaft in a casing, and as the impeller is rotated, a fluid such as an air, a gas, or the like, is suctioned from a suction port of the casing and a centrifugal force is applied thereto. Then, kinetic energy is converted into pressure energy by a diffuser and a scroll section to be delivered from a discharge port of the casing.
- In the above-mentioned centrifugal compressor, in order to limit the occurrences of suppress a rotating stall generated by uniformizing a flow in a circumferential direction, a diffuser width is set to be smaller than in the related art, or a circulation flow channel that connects an impeller back surface and a diffuser inlet is installed (for example, see Patent Literature 1 and Patent Literature 2).
- Even in both of the configurations, a structure in which the rotating stall cannot be easily generated is provided by increasing a flow velocity in a diffuser inlet and further reducing the flow angle of the flow in a radial direction.
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- Patent Literature 1: Japanese Unexamined Patent Application, First Publication No.
2011-122516 - Patent Literature 2: Japanese Unexamined Patent Application, First Publication No.
2010-043648 - Here, when the centrifugal compressor has the structure in which the circulation flow channel connects the impeller back surface and the diffuser inlet as disclosed in the above-mentioned Patent Literature 1 and
Patent Literature 2 is installed, some of a high pressure compressed fluid is ejected to the impeller back surface and not to the diffuser, in the structure. Accordingly, a leakage flow from a main stream to the impeller back surface is reduced, and a main stream velocity is maintained. However, there is a margin for improvement in increasing the flow velocity of the fluid that flows through the outlet flow channel. - In addition, a leakage from a seal (for example, a labyrinth seal) installed between a rotary shaft and a hub casing may be increased.
- An object of the present invention is to provide a centrifugal compressor capable of more securely limiting the occurrence of rotating stall by increasing the flow velocity of a fluid that flows through an outlet flow channel.
- According to a first aspect of the present invention, a centrifugal compressor includes: an impeller configured to discharge a fluid introduced toward one side in an axial direction from an outlet directed to the outside in a radial direction through rotation thereof; and a casing installed to surround the impeller and having an outlet flow channel through which a fluid sent from the outlet of the impeller flows downstream thereby increasing the pressure of the fluid therein further downstream in the flow direction, wherein a circulation flow channel having a first opening section connected to the outlet flow channel and a second opening section connected to an upstream side of the first opening section in the outlet flow channel is formed.
- According to the above-mentioned configuration, as the fluid introduced from the second opening section of the outlet flow channel is circulated to increase a flow velocity of the fluid flowing through the outlet flow channel, occurrences of rotating stall can be more securely limited.
- In the centrifugal compressor, the second opening section may be oriented toward the downstream side of the outlet flow channel.
- According to the above-mentioned configuration, since a circulation flow introduced from the second opening section is directed toward the downstream side of the outlet flow channel, a flow velocity of the fluid flowing through the outlet flow channel can be further increased.
- In the centrifugal compressor, the outlet flow channel may include: a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy, and a scroll connected to an outlet of the diffuser and configured to eject the fluid to the outside, and the first opening section may be formed at the scroll.
- According to the above-mentioned configuration, since a pressure difference between the first opening section and the second opening section can be further increased, the circulation flow can more securely flow.
- In the centrifugal compressor, the outlet flow channel may include a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy, and the first opening section may be formed at an outlet side of the diffuser.
- According to the present invention, as the fluid introduced from the second opening section of the outlet flow channel is circulated to increase the flow velocity of the fluid that flows through the outlet flow channel, occurrences of rotating stall can be more securely limited.
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Fig. 1 is a schematic cross-sectional view of a centrifugal compressor of an embodiment of the present invention. -
Fig. 2 is an enlarged view showing an impeller and a scroll section of a final stage in the centrifugal compressor of the embodiment of the present invention. -
Fig. 3 is an enlarged view showing an impeller and a scroll section of a final stage in a centrifugal compressor in a modification of the embodiment of the present invention. - Hereinafter, an embodiment of the present invention is described in detail with reference to the accompanying drawings. Further, in the embodiment, as an example of a centrifugal compressor, a multi-stage type centrifugal compressor having a plurality of impellers will be exemplarily described.
- As shown in
Fig. 1 , a centrifugal compressor 1 of the embodiment is generally constituted by arotary shaft 2 rotatable about an axis O, animpeller 3 attached to therotary shaft 2 and configured to compress a fluid G such as an air or the like using a centrifugal force, and acasing 5 configured to rotatably support therotary shaft 2 and having aflow channel 4 through which the fluid G flows from an upstream side toward a downstream side. - The
casing 5 is configured to form a substantially columnar contour, and the rotary shaft is disposed to pass through a center of thecasing 5. In thecasing 5,journal bearings 7 are installed at both ends of therotary shaft 2 in the axial direction, and a thrust bearing 8 is installed at one end thereof. The journal bearings 7 and the thrust bearing 8 rotatably support therotary shaft 2. That is, therotary shaft 2 is supported by thecasing 5 via thejournal bearings 7 and the thrust bearing 8. - In addition, a
suction port 9 configured to introduce the fluid G from the outside is formed at one end side of thecasing 5 in the axial direction and adischarge port 10 configured to discharge the fluid G to the outside is formed at the other end side. In thecasing 5, aninternal space 11 in communication with thesuction port 9 and thedischarge port 10 and having a diameter which is repeatedly increased and a decreased is provided. Theinternal space 11 functions as a space for accommodating theimpeller 3 and also functions as the above-mentionedflow channel 4. That is, thesuction port 9 and thedischarge port 10 are in communication with each other via theimpeller 3 and theflow channel 4. In addition, thecasing 5 is constituted by ashroud casing 5a and ahub casing 5b, and theinternal space 11 is defined by theshroud casing 5a and thehub casing 5b. - The plurality of
impellers 3 are arranged in the axial direction of therotary shaft 2 at intervals. Further, in the example shown, while siximpellers 3 are installed, at least one impeller may be installed. As shown inFig. 2 , each of theimpellers 3 is constituted by a substantially disk-shaped hub 13 having a diameter gradually increased toward thedischarge port 10, a plurality ofblades 14 radially attached to thehub 13 and disposed in a circumferential direction in parallel, and ashroud 15 attached to cover front end sides of the plurality ofblades 14 in the circumferential direction. - The
flow channel 4 is formed to advance in the axial direction and connect theimpellers 3 while meandering in the radial direction of therotary shaft 2 such that the fluid G is compressed by the plurality ofimpellers 3 in the stepped manner. Specifically describing, theflow channel 4 is generally constituted by asuction passage 17, acompression passage 18, adiffuser passage 19, and areturn passage 20. Thediffuser passage 19 is a passage configured to convert kinetic energy applied to the fluid by theimpellers 3 into pressure energy. - The
suction passage 17 is a passage configured to convert the direction of the fluid G into the axial direction of therotary shaft 2 immediately before theimpeller 3 after the fluid G flows from the outside in the radial direction toward the inside in the radial direction. Specifically, thesuction passage 17 is constituted by a straight passage 21 having a linear shape through which the fluid G flows from the outside in the radial direction toward the inside in the radial direction, and a corner passage 22 having a curved shape and configured to convert the flow direction of the fluid G flowing from the straight passage 21 from the inside in the radial direction into the axial direction to direct the fluid G toward theimpeller 3. - Further, a plurality of return vanes 23 radially disposed about the axis O and configured to divide the straight passage 21 in the circumferential direction of the
rotary shaft 2 are installed at the straight passage 21 disposed between the twoimpellers 3. - The
compression passage 18 is a passage configured to compress the fluid G conveyed from thesuction passage 17, in theimpeller 3, and is defined by being surrounded by a blade attachment surface of thehub 13 and an inner wall surface of theshroud 15. - The
diffuser passage 19 has an inside in the radial direction in communication with thecompression passage 18, and functions to allow the fluid G compressed by theimpeller 3 to flow outward in the radial direction. Further, while the outside in the radial direction of thediffuser passage 19 is in communication with thereturn passage 20, thediffuser passage 19 connected to the outside in the radial direction of theimpeller 3 disposed at the most downstream side of the flow channel 4 (inFig. 1 , the sixth impeller 3) is in communication with anejection scroll 12, which will be described below. - The
return passage 20 is formed with a substantially U-shaped cross section, an upstream end side of thereturn passage 20 is in communication with thediffuser passage 19, and a downstream end side is in communication with the straight passage 21 of thesuction passage 17. Thereturn passage 20 reverses the flow direction of the fluid G flowing to the outside in the radial direction through thediffuser passage 19 toward the inside in the radial direction due to the impeller 3 (theimpeller 3 of the upstream side), and delivers the fluid G to the straight passage 21. - The ejection scroll 12 configured to eject the fluid from the ejection port is formed in the
casing 5. Theejection scroll 12 has a scroll flow channel 25 formed to surround the entire circumference of the outlet of thediffuser passage 19 disposed at an outer circumferential section of theimpeller 3 of the final stage. - The scroll flow channel 25 is formed to surround the entire circumference of the outlet of the
diffuser passage 19 disposed at the outer circumferential section of theimpeller 3 of the final stage, and is formed to gradually and continuously enlarge a cross-sectional area thereof in a rotational direction of theimpeller 3. - The
diffuser passage 19 and the ejection scroll 12 function as anoutlet flow channel 6 configured to increase a pressure of the fluid as the fluid is directed toward the downstream side while the fluid provided from the outlet of theimpeller 3 flows therethrough. - Then, in the
casing 5 of the centrifugal compressor 1 of the embodiment, acirculation flow channel 26 connecting the bottom surface of the scroll flow channel 25 of theejection scroll 12 and thediffuser passage 19 is formed. Specifically, thecirculation flow channel 26 is theflow channel 4 having asecond opening section 28 formed in the vicinity of an inlet of thediffuser passage 19, and afirst opening section 27 formed at the bottom surface of the scroll flow channel 25. - The
second opening section 28 is formed to be directed toward the downstream side of thediffuser passage 19. That is, thesecond opening section 28 oriented such that the compressed air introduced from thefirst opening section 27 and ejected from thesecond opening section 28 is ejected toward the outlet of thediffuser passage 19. - Next, compression of the fluid G by the centrifugal compressor 1 configured as described above will be described. When the
impellers 3 are rotated with therotary shaft 2, the fluid G introduced into theflow channel 4 from thesuction port 9 flows sequentially into thesuction passage 17, thecompression passage 18, thediffuser passage 19 and thereturn passage 20 of theimpeller 3 of the first stage from thesuction port 9, and then, flows sequentially into thesuction passage 17, thecompression passage 18... of theimpeller 3 of the second stage. Then, the fluid G flowing to theejection scroll 12 immediately after thediffuser passage 19 disposed at the most downstream side of theflow channel 4 flows to the outside from thedischarge port 10. - The fluid G is compressed by the
impellers 3 in the middle of flowing through theflow channel 4 in the above-mentioned sequence. That is, in the centrifugal compressor 1, the fluid G is compressed by the plurality ofimpellers 3 in the stepped manner, and thus, a large compression ratio can be easily obtained. - Here, the
circulation flow channel 26 is configured to capture some of the compressed fluid from thefirst opening section 27 and eject the compressed fluid from thesecond opening section 28 such that some of the compressed fluid is circulated between thediffuser passage 19 and theejection scroll 12. - According to the embodiment, the compressed air is introduced from the
first opening section 27 of the scroll flow channel 25 to be ejected from thesecond opening section 28 of thediffuser passage 19 via thecirculation flow channel 26. That is, the compressed air is circulated to increase a flow velocity of the fluid flowing through thediffuser passage 19 with the compressed fluid. Accordingly, occurrences of rotating stall can be more securely limited. - In addition, as the
second opening section 28 is formed to be oriented toward the downstream side of thediffuser passage 19, since the compressed fluid introduced from thesecond opening section 28 is ejected toward the downstream side of thediffuser passage 19, the flow velocity of the fluid flowing through thediffuser passage 19 can be further increased. - In addition, as the
first opening section 27 is formed at theejection scroll 12, since a pressure difference between thefirst opening section 27 and thesecond opening section 28 is further increased, a circulation flow can more securely flow. - Further, since no compressed air is introduced onto the back surface of the
impeller 3, for example, when the seal such as a labyrinth seal or the like is installed between therotary shaft 2 and thecasing 5, a leakage from the seal is not increased. - Further, in the embodiment, while a configuration in which the
first opening section 27 of thecirculation flow channel 26 is formed at theejection scroll 12 is provided, a formed place of thefirst opening section 27 may be a downstream side of thesecond opening section 28 on the outlet flow channel constituted by thediffuser passage 19 and theejection scroll 12. For example, as shown inFig. 3 , a configuration in which thefirst opening section 27 is formed at the outlet side of thediffuser passage 19 may be provided. - Further, the technical spirit of the present invention is not limited to the embodiment and various modifications may be made without departing from the spirit of the present invention.
- For example, the
circulation flow channel 26 may be branched off from a conventional line to eject the fluid to thediffuser passage 19 without necessity of newly forming the entire circulation flow channel. - In addition, in the embodiment, while the
second opening section 28 is configured to be oriented toward a slipstream side of thediffuser passage 19, it is not limited thereto as long the flow velocity of the compressed fluid flowing through thediffuser passage 19 should not decreased. For example, the fluid may be injected in a direction perpendicular to the extending direction of thediffuser passage 19. - According to the centrifugal compressor, occurrences of rotating stall can be more securely limited by circulating the fluid such that the fluid introduced from the second opening section of the outlet flow channel increases the flow velocity of the fluid flowing through the outlet flow channel.
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- 1
- centrifugal compressor
- 2
- rotary shaft
- 3
- impeller
- 4
- flow channel
- 5
- casing
- 6
- outlet flow channel
- 9
- suction port
- 10
- discharge port
- 11
- internal space
- 12
- ejection scroll
- 13
- hub
- 14
- blade
- 15
- shroud
- 17
- suction passage
- 18
- compression passage
- 19
- diffuser passage
- 20
- return passage
- 21
- straight passage
- 22
- corner passage
- 23
- return vane
- 25
- scroll flow channel
- 26
- circulation flow channel
- 27
- first opening section
- 28
- second opening section
Claims (4)
- A centrifugal compressor comprising:an impeller configured to discharge a fluid introduced toward one side in an axial direction from an outlet of the impeller directed to the outside in a radial direction through rotation thereof; anda casing installed to surround the impeller and having an outlet flow channel through which a fluid sent from the outlet of the impeller flows downstream thereby increasing a pressure of the fluid therein further downstream in the flow direction,wherein a circulation flow channel having a first opening section connected to the outlet flow channel and a second opening section connected to an upstream side of the first opening section in the outlet flow channel is formed.
- The centrifugal compressor according to claim 1, wherein the second opening section is oriented toward the downstream side of the outlet flow channel.
- The centrifugal compressor according to claim 1 or 2, wherein the outlet flow channel includes:a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy;a scroll connected to an outlet of the diffuser and configured to eject the fluid to the outside; andthe first opening section is formed at the scroll.
- The centrifugal compressor according to claim 1 or 2, wherein the outlet flow channel includes a diffuser connected to the outlet of the impeller and configured to convert kinetic energy applied to the fluid by the impeller into pressure energy, and
the first opening section is formed at an outlet side of the diffuser.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013020704A JP2014152637A (en) | 2013-02-05 | 2013-02-05 | Centrifugal compressor |
PCT/JP2013/076373 WO2014122819A1 (en) | 2013-02-05 | 2013-09-27 | Centrifugal compressor |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2955387A1 true EP2955387A1 (en) | 2015-12-16 |
EP2955387A4 EP2955387A4 (en) | 2016-09-07 |
Family
ID=51299428
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13874463.6A Withdrawn EP2955387A4 (en) | 2013-02-05 | 2013-09-27 | Centrifugal compressor |
Country Status (5)
Country | Link |
---|---|
US (1) | US20150354588A1 (en) |
EP (1) | EP2955387A4 (en) |
JP (1) | JP2014152637A (en) |
CN (1) | CN104822948A (en) |
WO (1) | WO2014122819A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9618013B2 (en) * | 2013-07-17 | 2017-04-11 | Rotational Trompe Compressors, Llc | Centrifugal gas compressor method and system |
JP6184018B2 (en) * | 2014-02-06 | 2017-08-23 | 三菱重工業株式会社 | Intermediate suction diaphragm and centrifugal rotating machine |
JP6642189B2 (en) * | 2016-03-29 | 2020-02-05 | 三菱重工コンプレッサ株式会社 | Centrifugal compressor |
JP6935312B2 (en) * | 2017-11-29 | 2021-09-15 | 三菱重工コンプレッサ株式会社 | Multi-stage centrifugal compressor |
KR102545557B1 (en) * | 2018-06-12 | 2023-06-21 | 엘지전자 주식회사 | Centrifugal Compressor |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1403519A1 (en) * | 1961-06-24 | 1969-12-11 | Gutehoffnungshuette Sterkrade | Device for boundary layer suction in turbo machines, in particular radial compressors |
JPS4847605A (en) * | 1971-10-19 | 1973-07-06 | ||
US4131389A (en) * | 1975-11-28 | 1978-12-26 | The Garrett Corporation | Centrifugal compressor with improved range |
US4695224A (en) * | 1982-01-04 | 1987-09-22 | General Electric Company | Centrifugal compressor with injection of a vaporizable liquid |
JP2005240680A (en) * | 2004-02-26 | 2005-09-08 | Mitsubishi Heavy Ind Ltd | Centrifugal compressor |
US8122724B2 (en) * | 2004-08-31 | 2012-02-28 | Honeywell International, Inc. | Compressor including an aerodynamically variable diffuser |
JP4655603B2 (en) * | 2004-12-01 | 2011-03-23 | 株式会社豊田自動織機 | Centrifugal compressor |
EP1710442A1 (en) * | 2005-04-04 | 2006-10-11 | ABB Turbo Systems AG | Flow stabilisation system for radial compressor |
JP5031012B2 (en) | 2006-07-13 | 2012-09-19 | 三菱重工業株式会社 | Compressor and operation control method thereof |
JP2010151033A (en) * | 2008-12-25 | 2010-07-08 | Ihi Corp | Centrifugal compressor |
JP2010151032A (en) * | 2008-12-25 | 2010-07-08 | Ihi Corp | Centrifugal compressor |
JP2010151031A (en) * | 2008-12-25 | 2010-07-08 | Ihi Corp | Centrifugal compressor |
JP5479021B2 (en) * | 2009-10-16 | 2014-04-23 | 三菱重工業株式会社 | Exhaust turbocharger compressor |
JP2011122516A (en) | 2009-12-10 | 2011-06-23 | Mitsubishi Heavy Ind Ltd | Centrifugal compressor |
FR2958967B1 (en) * | 2010-04-14 | 2013-03-15 | Turbomeca | METHOD FOR ADJUSTING TURBOMACHINE AIR FLOW WITH CENTRIFUGAL COMPRESSOR AND DIFFUSER THEREFOR |
-
2013
- 2013-02-05 JP JP2013020704A patent/JP2014152637A/en active Pending
- 2013-09-27 CN CN201380062485.0A patent/CN104822948A/en active Pending
- 2013-09-27 WO PCT/JP2013/076373 patent/WO2014122819A1/en active Application Filing
- 2013-09-27 US US14/759,373 patent/US20150354588A1/en not_active Abandoned
- 2013-09-27 EP EP13874463.6A patent/EP2955387A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
CN104822948A (en) | 2015-08-05 |
WO2014122819A1 (en) | 2014-08-14 |
JP2014152637A (en) | 2014-08-25 |
US20150354588A1 (en) | 2015-12-10 |
EP2955387A4 (en) | 2016-09-07 |
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