EP3196476A1 - Impeller, centrifugal compressor and refrigeration cycle apparatus - Google Patents

Impeller, centrifugal compressor and refrigeration cycle apparatus Download PDF

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Publication number
EP3196476A1
EP3196476A1 EP17152121.4A EP17152121A EP3196476A1 EP 3196476 A1 EP3196476 A1 EP 3196476A1 EP 17152121 A EP17152121 A EP 17152121A EP 3196476 A1 EP3196476 A1 EP 3196476A1
Authority
EP
European Patent Office
Prior art keywords
impeller
leading edge
wing
hub
wings
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.)
Withdrawn
Application number
EP17152121.4A
Other languages
German (de)
English (en)
French (fr)
Inventor
Hidetoshi Taguchi
Akira Hiwata
Takeshi Ogata
Tadayoshi SHOYAMA
Kazuyuki Kouda
Kota KIMURA
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Panasonic Intellectual Property Management Co Ltd
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Panasonic Intellectual Property Management Co Ltd
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Filing date
Publication date
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Publication of EP3196476A1 publication Critical patent/EP3196476A1/en
Withdrawn legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/18Rotors
    • F04D29/22Rotors specially for centrifugal pumps
    • F04D29/24Vanes
    • F04D29/242Geometry, shape
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/26Rotors specially for elastic fluids
    • F04D29/28Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
    • F04D29/284Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for compressors
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02Blade-carrying members, e.g. rotors
    • F01D5/04Blade-carrying members, e.g. rotors for radial-flow machines or engines
    • F01D5/043Blade-carrying members, e.g. rotors for radial-flow machines or engines of the axial inlet- radial outlet, or vice versa, type
    • F01D5/048Form or construction
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/18Rotors
    • F04D29/22Rotors specially for centrifugal pumps
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/26Rotors specially for elastic fluids
    • F04D29/28Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
    • F04D29/30Vanes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00Compression machines, plants or systems with non-reversible cycle
    • F25B1/04Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
    • F25B1/053Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of turbine type
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00Compression machines, plants or systems with non-reversible cycle
    • F25B1/10Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00Components
    • F05D2240/20Rotors
    • F05D2240/30Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/307Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the tip of a rotor blade
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00Geometry
    • F05D2250/70Shape
    • F05D2250/71Shape curved

Definitions

  • the present disclosure relates to an impeller, a centrifugal compressor, and a refrigeration cycle apparatus.
  • an impeller applies kinetic energy to a fluid in a manner in which the fluid inhaled is accelerated mainly in a direction of the tangent of rotation.
  • the impeller typically has an approximately truncated cone shape and rotates about a line connecting the center of its upper surface having a small diameter and the center of its lower surface having a large diameter.
  • an impeller has wings (blades) radially arranged.
  • each wing collides, at an angle, with a fluid inhaled into a centrifugal compressor.
  • the collision makes a difference in velocity between the front surface (suction surface) and back surface (pressure surface) of the wing, applying kinetic energy to the fluid.
  • an increase in the radius of gyration of the impeller increases a velocity component of the fluid mainly in the direction of the tangent of rotation.
  • the increase in the velocity component is at its maximum, and the total amount of the kinetic energy applied to the fluid is determined.
  • the impeller is designed such that the sectional area throughout the wing gradually decreases from the leading edge of the wing to the trailing edge thereof, the velocity of the fluid in the direction parallel to the front surface of the wing can be prevented from decreasing.
  • the velocity of the fluid in the inside (channels between the wings) of the impeller depends on a pressure ratio for which a compressor equipped with the impeller is required.
  • a pressure ratio for which a compressor equipped with the impeller is required For example, in the case where the fluid to be compressed is air, and in the case of a compressor having a pressure ratio of more than 4, the velocity (relative velocity) of the fluid when the fluid is seen from the wing side at the leading edge of the wing reaches a transonic speed.
  • a centrifugal compressor whose target pressure ratio is 8 is described in Colin Osborne et al.
  • the flow of the fluid in channels between the wings of the impeller is very complex.
  • a vortex flow vortex flow having a high vorticity of flow
  • a low velocity and a high intensity is created, and accordingly, an efficient application of kinetic energy to the fluid from the wings is hindered.
  • the friction of the fluid in the vortex flow causes a loss. This lowers the pressure ratio and an adiabatic efficiency.
  • One non-limiting and exemplary embodiment provides a technique for appropriately adjusting the distribution of the velocity of the fluid in the channels between the wings and for improving the efficiency of the centrifugal compressor.
  • the techniques disclosed here feature an impeller for a centrifugal compressor including a hub that has an upper surface, a lower surface, and an outer surface, and wings that are fixed to the hub and that are arranged radially around the outer surface of the hub.
  • Awing has a leading edge portion and a body portion. The wing is each of the wings.
  • the leading edge portion is positioned on an upper surface side of the hub.
  • the body portion is positioned on a lower surface side of the hub.
  • the leading edge portion includes a leading edge.
  • a tip of the leading edge portion and a tip of the body portion extend from the upper surface side of the hub toward the lower surface side of the hub on a side opposite to a side where the wing is fixed to the hub.
  • a profile of the tip of the leading edge portion has a linear shape and a profile of the tip of the body portion has a curved shape.
  • the distribution of the velocity of the fluid in the channels between the wings can be appropriately adjusted to improve the efficiency of the centrifugal compressor.
  • the present inventors have analyzed the flow of a fluid (for example, water vapor) in the inside (channels between wings) of an impeller in detail and consequently found that merging and breakdown of large vortex flows result in the production of a region in which a flow is blocked (region in which the velocity of the flow is very low) inside the impeller.
  • the present inventors have diligently examined the shape of a wing that enables the large vortex flows to be inhibited from merging and breaking down and consequently considered the impeller according to the present disclosure.
  • An impeller according to a first aspect of the present disclosure is an impeller for a centrifugal compressor including a hub that has an upper surface, a lower surface, and an outer surface, and wings that are fixed to the hub and that are arranged radially around the outer surface of the hub.
  • a wing has a leading edge portion and a body portion.
  • the wing is each of the wings.
  • the leading edge portion is positioned on an upper surface side of the hub.
  • the body portion is positioned on a lower surface side of the hub.
  • the leading edge portion includes a leading edge.
  • a tip of the leading edge portion and a tip of the body portion extend from the upper surface side of the hub toward the lower surface side of the hub on a side opposite to a side where the wing is fixed to the hub.
  • a profile of the tip of the leading edge portion has a linear shape and a profile of the tip of the body portion has a curved shape.
  • the impeller according to the first aspect of the present disclosure that is expressed in another way is an impeller for a centrifugal compressor including a hub that has an upper surface, a lower surface, and an outer surface, and wings that are fixed to the hub and that are arranged radially around the outer surface of the hub.
  • a wing has a leading edge portion and a body portion.
  • the wing is each of the wings.
  • the leading edge portion is positioned on an upper surface side of the hub.
  • the body portion is positioned on a lower surface side of the hub.
  • the leading edge portion includes a leading edge. The leading edge constitutes one edge of the wing in a direction parallel to an axis of the impeller.
  • a tip of the leading edge portion and a tip of the body portion extend from the upper surface side of the hub toward the lower surface side of the hub.
  • the tip of the leading edge portion and the tip of the body portion constitutes one edge of the wing opposite to the other edge of the wing where the wing is fixed to the hub in a radial direction perpendicular to the axis of the impeller.
  • a profile of the tip of the leading edge portion has a linear shape and a profile of the tip of the body portion has a curved shape.
  • the impeller according to the first aspect even when the separation of a boundary layer and/or a leakage flow at the wing edge cause high-intensity vortex flows to be produced in the inside (channels between the wings) of the impeller, the vortex flows can be inhibited from merging and becoming large. In other words, the distribution of the velocity of the fluid in the channels between the wings can be appropriately adjusted. Consequently, blocking on the inside of the impeller is inhibited, the fluid flows smoothly, and kinetic energy can be efficiently applied from the wings to the fluid.
  • the performance of the compressor can be maintained even under operating conditions of a low Reynolds number and a low specific speed.
  • the use of the impeller according to the first aspect enables a low-density, high-viscosity fluid (for example, water vapor) to be highly efficiently compressed.
  • each of the wings of the impeller according to the first aspect has a pressure surface and a suction surface.
  • the profile of the tip of the leading edge portion includes a first upstream portion on a pressure surface side and a second upstream portion on a suction surface side, and the first upstream portion and the second upstream portion have a linear shape.
  • the profile of the tip of the body portion includes a first downstream portion on the pressure surface side and a second downstream portion on the suction surface side, and the first downstream portion and the second downstream portion have a curved shape.
  • the leading edge portion occupies a portion of the wing extending from the leading edge to a position 5% of the meridional plane length away from the leading edge in the axial direction in the projection view of the meridional plane.
  • the wings of the impeller form respective main wings of the impeller.
  • the impeller further includes sub wings.
  • Each of the sub wings is disposed between the main wings that are adjacent to one another in a circumferential direction of the impeller.
  • the sub wings may have the sectional shape of the main wings.
  • a centrifugal compressor having a wider range of the flow rate can be formed.
  • a ratio of the radius of the hub to the radius of each of the wings of the impeller according to any one of the first to fourth aspects ranges from 0.6 to 0.7 at the leading edge of the wing. According to the fifth aspect, the disturbance of the flow field can be effectively inhibited, and the pressure ratio can be increased.
  • a centrifugal compressor according to a sixth aspect of the present disclosure includes the impeller according to any one of the first to fifth aspects and a shroud wall accommodating the impeller. According to the sixth aspect, a highly efficient centrifugal compressor can be provided.
  • a refrigeration cycle apparatus includes the centrifugal compressor according to the sixth aspect.
  • a material whose saturated vapor pressure is a negative pressure at a normal temperature is used as a refrigerant. According to the seventh aspect, the pressure of the refrigerant can be efficiently increased, and accordingly, the efficiency of the refrigeration cycle apparatus can be improved.
  • the material in the refrigeration cycle apparatus according to the seventh aspect contains water.
  • the centrifugal compressor that uses the impeller according to the present disclosure is suitable for efficiently compressing a refrigerant containing water (water vapor).
  • a centrifugal compressor 100 includes a shaft 11, an impeller 2, a back plate 13, and a housing 15.
  • the impeller 2 is fixed to the shaft 11.
  • the back plate 13 is disposed on the back side of the impeller 2.
  • the impeller 2 is accommodated in the housing 15.
  • the centrifugal compressor 100 is driven by rotation of the shaft 11 and compresses a working fluid.
  • the front surface side of the back plate 13 in a direction (axial direction) parallel to the axis O of the impeller 2 is also referred to as a front side
  • the back surface side thereof in the direction is also referred to as a back side.
  • the impeller 2 includes a hub 20, main wings 21 (full blades), and sub wings 22 (splitter blades).
  • the hub 20 has an upper surface 20p having a small diameter and a lower surface 20q having a large diameter in the axial direction, and the diameter of the hub 20 smoothly increases from the upper surface 20p to the lower surface 20q along the axis O.
  • the main wings 21 and the sub wings 22 are fixed to the hub 20 and arranged radially around the outer surface of the hub 20.
  • the main wings 21 and the sub wings 22 are arranged so as to alternate in the circumferential direction of the impeller 2.
  • the sub wings 22 are wings shorter than the main wings 21.
  • the sub wings 22 are not essential and may be omitted.
  • the housing 15 has a shroud wall 3, a peripheral member 17, and a front member 18.
  • the shroud wall 3 has a shape extending along the impeller 2.
  • the shroud wall 3 protrudes from the impeller 2 toward the front side and forms an inhalation port 12.
  • the peripheral member 17 forms a scroll chamber 16 around the impeller 2, and the scroll chamber 16 is in communication with a diffuser formed between the back plate 13 and the shroud wall 3.
  • Fig. 2 is a projection view of a meridional plane (rotation projection view) that is obtained in a manner in which the main wings 21, the sub wings 22, and the shroud wall 3 are rotationally projected on the meridional plane containing the axis O of the impeller 2.
  • a shape illustrated on the projection view of the meridional plane is called "a meridional plane shape" in the field of turbomachinery.
  • the outer circumferential edge of each main wing 21 facing the inhalation port 12 is defined as the leading edge 31 of the main wing 21.
  • the outer circumferential edge of each main wing 21 facing the shroud wall 3 is defined as the tip 32 of the main wing 21.
  • each sub wing 22 facing the inhalation port 12 is defined as the leading edge 41 of the sub wing 22.
  • the outer circumferential edge of each sub wing 22 facing the shroud wall 3 is defined as the tip 42 of the sub wing 22.
  • the leading edges 31 and 41 are positioned on the same side in the axial direction as the upper surface 20p of the hub 20.
  • the leading edge 31 of the main wing 21 is perpendicular to the axis O of the impeller 2.
  • the trailing edge 43 of the sub wing 22 is positioned at the same position as the trailing edge 33 of the main wing 21.
  • the leading edge 41 of the sub wing 22 is positioned at a position away from the leading edge 31 of the main wing 21 toward the rear side.
  • the leading edge 31 constitutes one edge of the main wing 21 in the direction parallel to the axis of the impeller 2.
  • each main wing 21 has a leading edge portion 24 positioned on the side of the upper surface 20p of the hub 20 and a body portion 25 positioned on the side of the lower surface 20q of the hub 20.
  • the body portion 25 is smoothly connected to the leading edge portion 24.
  • the tip 35 of the leading edge portion 24 and the tip 36 of the body portion 25 extend from the side of the upper surface 20p of the hub 20 toward the side of the lower surface 20q of the hub 20 on a side opposite to a side where the main wing 21 is fixed to the hub 20.
  • the profile of the tip 35 of the leading edge portion 24 has a linear shape
  • the profile of the tip 36 of the body portion 25 has a curved shape
  • a boundary 37 at which the main wing 21 is connected to the hub 20 has a curved shape overall from the leading edge 31 to the trailing edge 33.
  • the axis O extends along the boundary between the leading edge portion 24 having a linear shape and the body portion 25 having a curved shape.
  • the leading edge portion 24 includes the leading edge 31.
  • the tip 35 of the leading edge portion 24 and the tip 36 of the body portion 25 constitute one edge of the main wing 21 opposite to the other edge of the main wing 21 where the main wing 21 is fixed to the hub 20 in the radial direction perpendicular to the axis of the impeller 2.
  • each main wing 21 has a pressure surface 21 p and a suction surface 21 q.
  • the surface of the main wing 21 on the rotation direction side of the impeller 2 is the pressure surface 21 p (pressing surface), and the surface of the main wing 21 opposite to the pressure surface 21 p is the suction surface 21 q (non-pressing surface).
  • the surface of each sub wing 22 on the rotation direction side of the impeller 2 is a pressure surface, and the surface of the sub wing 22 opposite to the pressure surface is a suction surface.
  • Impellers disclosed in International Publication No. 2014/073377 , International Publication No. 2014/199498 , Japanese Unexamined Patent Application Publication No. 2011-117346 , and U.S. Patent Application Publication No. 2008/0229742 are assumed to be used under conditions in which the Reynolds number Re becomes about 10 6 .
  • a centrifugal compressor as a component of a motor such as a supercharger or a gas turbine that uses air as a working fluid is assumed.
  • the Reynolds number Re is expressed by the following formula (1).
  • [Formula 1] Re ⁇ ⁇ R T ⁇ W T v
  • centrifugal compressors used in, for example, air-conditioning apparatuses
  • a compressible fluid other than air is used as the working fluid.
  • a decrease in the viscosity of the working fluid decreases Re to about 10 4 .
  • These cases have a problem in that high-intensity vortex flows are frequently created from the surface of the hub and the surface of the wings. Mutual influence between the high-intensity vortex flows causes a large disturbance inside the impeller. Consequently, the performance of the centrifugal compressors is greatly reduced.
  • the profile of the tip 210a of a wing 210 on the pressure surface side and the profile of the tip 210b of the wing 210 on the suction surface side have a curved shape overall. Accordingly, a fluid that collides with a leading edge 210c is immediately accelerated. In this case, mutual influence between the high-intensity vortex flows is likely to cause a large disturbance inside the impeller.
  • each main wing 21 has the leading edge portion 24. Since the profile of the tip 35 of the leading edge portion 24 has a linear shape, the fluid is unlikely to be accelerated at the leading edge portion 24. Consequently, the boundary layer is inhibited from expanding, and a position at which a low-energy, high-intensity vortex flow due to the separation of the boundary layer is created shifts to the side that is more downstream than in the case of the conventional wing 210 ( Fig. 7 ).
  • the flows are decelerated on the side of the suction surface 21q of the leading edge portion 24 and accelerated on the side of the pressure surface 21p. Since the flows are decelerated on the side of the suction surface 21q, the boundary layer is inhibited from expanding and from being separated. Since the flows are accelerated on the pressure surface side, a low-energy flow that is created on the side of the suction surface 21q of the adjacent main wing 21 due to the separated boundary layer can be diverted. The low-energy flow can be prevented from being maintained on the pressure surface 21p and re-collides with the suction surface 21q of the main wing 21 from which the flow has been separated. This inhibits the disturbance of the velocity distribution of the fluid on the pressure surface 21p of the main wing 21 due to a secondary flow originated from the adjacent main wing 21 and enables the velocity distribution to be appropriately adjusted.
  • the profile of the tip 35 of the leading edge portion 24 includes a first upstream portion 35a on the side of the pressure surface 21p and a second upstream portion 35b on the side of the suction surface 21q.
  • the first upstream portion 35a and the second upstream portion 35b have a linear shape.
  • the profile of the tip 36 of the body portion 25 includes a first downstream portion 36a on the side of the pressure surface 21p and a second downstream portion 36b on the side of the suction surface 21q.
  • the first downstream portion 36a and the second downstream portion 36b have a curved shape.
  • the first downstream portion 36a and the second downstream portion 36b have a curvature so as to bend into a convex shape toward the side of the suction surface 21q.
  • each main wing 21 in the axial direction parallel to the axis O of the impeller 2 is defined as a meridional plane length L.
  • the leading edge portion 24 occupies a portion of the wing 21 extending from the leading edge 31 to a position 5% of the meridional plane length L away from the leading edge 31 in the axial direction in the projection view of the meridional plane in Fig. 2 .
  • the body portion 25 occupies a portion of the main wing 21 extending from the position 5% of the meridional plane length L away from the leading edge 31 to the trailing edge 33.
  • the leading edge portion 24 is exaggeratedly illustrated. The limitation of the range of the leading edge portion 24 to a certain degree reduces the likelihood of the wings 21 having insufficient length and accordingly enables sufficient energy to be applied to the fluid.
  • the impeller 2 has a hub-tip ratio (D1/D2) of 0.6 to 0.7.
  • the term "hub-tip ratio” means a ratio (D1/D2) of the radius D1 of the hub 20 to the radius D2 of each main wing 21 at the leading edge 31 of the main wing 21. In the case where the hub-tip ratio is in the above range, the following effects are achieved.
  • a typically designed impeller of a centrifugal compressor has a hub-tip ratio of about 0.4 to 0.5.
  • the hub-tip ratio ranges from 0.6 to 0.7
  • the inflow rate of the fluid entering the impeller 2 increases, and the pressure ratio is likely to increase.
  • the disturbance of the flow field and a reduction in performance due to the disturbance are likely to manifest themselves. Accordingly, in the case where the main wings 21 having the structure described with reference to Fig. 3A and Fig. 3B are used in the impeller having a hub-tip ratio of 0.6 to 0.7, the disturbance of the flow field can be effectively inhibited, and the pressure ratio can be increased.
  • a refrigeration cycle apparatus 200 includes a main circuit 6 through which a refrigerant circulates, a first circulation path 7 for heat absorption and a second circulation path 8 for heat dissipation.
  • the main circuit 6, the first circulation path 7, and the second circulation path 8 are filled with the refrigerant that is a liquid at a normal temperature.
  • the refrigerant is a refrigerant whose saturated vapor pressure is a negative pressure at a normal temperature (Japanese Industrial Standards: 20°C ⁇ 15°C / JIS Z8703). Examples of such a refrigerant include a refrigerant whose main component is water or alcohol.
  • the pressure of the inside of the main circuit 6, the first circulation path 7, and the second circulation path 8 is a negative pressure lower than an atmospheric pressure.
  • the term "main component" in the present disclosure means the most abundant component at a mass ratio.
  • the main circuit 6 includes an evaporator 66, a first compressor 61, an intermediate refrigerator 62, a second compressor 63, a condenser 64, and an expansion valve 65. These components are connected in this order along a channel.
  • the evaporator 66 stores a refrigerant liquid and evaporates the refrigerant liquid in the inside thereof. Specifically, the refrigerant liquid stored in the evaporator 66 circulates through the first circulation path 7 via a heat exchanger 71 for heat absorption.
  • the heat exchanger 71 for heat absorption is installed inside the room and exchanges heat between air inside the room supplied from a fan and the refrigerant liquid to cool the air.
  • the first compressor 61 and the second compressor 63 compress refrigerant vapor through two stages.
  • the centrifugal compressor 100 described above can be used as the first compressor 61.
  • the second compressor 63 may be a displacement-type compressor separated from the first compressor 61 or a centrifugal compressor (for example, the centrifugal compressor 100 described above) connected to the first compressor 61 by using the shaft 11.
  • An electric motor 67 that rotates the shaft 11 may be disposed between the first compressor 61 and the second compressor 63 or outside one of the first and second compressors. Connecting the first compressor 61 and the second compressor 63 by using the shaft 11 enables the number of the components of the first compressor 61 and the second compressor 63 to be decreased.
  • the intermediate refrigerator 62 cools the refrigerant vapor discharged from the first compressor 61 before the refrigerant vapor is inhaled into the second compressor 63.
  • the intermediate refrigerator 62 may be a direct-contact-type heat exchanger or an indirect type heat exchanger.
  • the condenser 64 condenses the refrigerant vapor in the inside thereof and stores the refrigerant liquid. Specifically, the refrigerant liquid stored in the condenser 64 circulates through the second circulation path 8 via a heat exchanger 81 for heat dissipation.
  • the heat exchanger 81 for heat dissipation is installed outside the room and exchanges heat between air outside the room supplied from a fan and the refrigerant liquid to heat the air.
  • the refrigeration cycle apparatus 200 is not necessarily an air-conditioning apparatus for cooling only.
  • a first heat exchanger installed inside a room and a second heat exchanger installed outside the room are connected to the evaporator 66 and the condenser 64 with a four-way valve interposed therebetween.
  • This achieves an air-conditioning apparatus that can change its operation between a cooling operation and a heating operation.
  • the first heat exchanger and the second heat exchanger both function as the heat exchanger 71 for heat absorption and the heat exchanger 81 for heat dissipation.
  • the refrigeration cycle apparatus 200 is not necessarily an air-conditioning apparatus and may be, for example, a chiller.
  • a subject to be cooled by the heat exchanger 71 for heat absorption and a subject to be heated by the heat exchanger 81 for heat dissipation may be a gas other than air or a liquid.
  • the expansion valve 65 is an example of a pressure-reducing mechanism that reduces the pressure of a condensed refrigerant liquid.
  • the pressure-reducing mechanism may be formed, for example, such that the expansion valve 65 is not disposed in the main circuit 6, and the liquid surface of the refrigerant liquid in the evaporator 66 is higher than the liquid surface of the refrigerant liquid in the condenser 64.
  • the evaporator 66 is not necessarily a direct-contact-type heat exchanger and may be an indirect type heat exchanger. In this case, a heating medium cooled in the evaporator 66 circulates through the first circulation path 7.
  • the condenser 64 is not necessarily a direct-contact-type heat exchanger and may be an indirect type heat exchanger. In this case, a heating medium heated in the condenser 64 circulates through the second circulation path 8.
  • the first compressor 61 and the second compressor 63 compress water vapor having a negative pressure.
  • the centrifugal compressor 100 described above is suitable for compressing a low-density, high-viscosity fluid such as water vapor.
  • the refrigeration cycle apparatus 200 can operate under conditions in which the flow rate of the fluid is small against the required pressure ratio, that is, the Reynolds number is low and the specific speed is low. Accordingly, the centrifugal compressor 100 described above is suitable for the refrigeration cycle apparatus 200 according to the embodiment.
  • the performance of the compressor can be maintained even under operating conditions of a low Reynolds number and a low specific speed.
  • the technique disclosed in the present disclosure is suitable for a refrigeration cycle apparatus that uses a natural refrigerant such as water vapor.
  • the performance of a small-output refrigeration cycle apparatus can be improved, and the frequency of the maintenance of the refrigeration cycle apparatus can be decreased.

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  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Geometry (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP17152121.4A 2016-01-25 2017-01-19 Impeller, centrifugal compressor and refrigeration cycle apparatus Withdrawn EP3196476A1 (en)

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DE102017215085A1 (de) * 2017-08-29 2019-02-28 Efficient Energy Gmbh Wärmepumpe mit einer Kühlvorrichtung zum Kühlen eines Leitraums oder eines Saugmunds
CN107989823B (zh) * 2017-12-26 2023-12-01 北京伯肯节能科技股份有限公司 叶轮、离心压缩机及燃料电池系统
CN111655385B (zh) * 2018-02-05 2022-11-11 富士胶片株式会社 被记录介质的制造方法及图像记录方法
CN109184804B (zh) * 2018-11-02 2021-04-13 北京控制工程研究所 一种空间布雷顿循环系统用的透平叶轮
US11286779B2 (en) 2020-06-03 2022-03-29 Honeywell International Inc. Characteristic distribution for rotor blade of booster rotor

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GB210353A (ja) * 1923-01-31 1924-01-31 Erste Bruenner Maschinen-Fabriks-Gesellschaft
GB594538A (en) * 1944-09-18 1947-11-13 British Thomson Houston Co Ltd Improvements in centrifugal type impellers for compressors and the like
US3904308A (en) * 1973-05-16 1975-09-09 Onera (Off Nat Aerospatiale) Supersonic centrifugal compressors
US20080229742A1 (en) 2007-03-21 2008-09-25 Philippe Renaud Extended Leading-Edge Compressor Wheel
JP2011117346A (ja) 2009-12-02 2011-06-16 Mitsubishi Heavy Ind Ltd 遠心圧縮機の羽根車
WO2013093479A2 (en) * 2011-12-21 2013-06-27 Venus Systems Limited Centrifugal refrigerant vapour compressors
WO2014073377A1 (ja) 2012-11-06 2014-05-15 三菱重工業株式会社 遠心回転機械のインペラ、遠心回転機械
WO2014199498A1 (ja) 2013-06-13 2014-12-18 三菱重工業株式会社 インペラ及び流体機械
CN204312394U (zh) * 2014-11-13 2015-05-06 湖南天雁机械有限责任公司 带压气机斜流叶轮的涡轮增压器

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GB210353A (ja) * 1923-01-31 1924-01-31 Erste Bruenner Maschinen-Fabriks-Gesellschaft
GB594538A (en) * 1944-09-18 1947-11-13 British Thomson Houston Co Ltd Improvements in centrifugal type impellers for compressors and the like
US3904308A (en) * 1973-05-16 1975-09-09 Onera (Off Nat Aerospatiale) Supersonic centrifugal compressors
US20080229742A1 (en) 2007-03-21 2008-09-25 Philippe Renaud Extended Leading-Edge Compressor Wheel
JP2011117346A (ja) 2009-12-02 2011-06-16 Mitsubishi Heavy Ind Ltd 遠心圧縮機の羽根車
WO2013093479A2 (en) * 2011-12-21 2013-06-27 Venus Systems Limited Centrifugal refrigerant vapour compressors
WO2014073377A1 (ja) 2012-11-06 2014-05-15 三菱重工業株式会社 遠心回転機械のインペラ、遠心回転機械
WO2014199498A1 (ja) 2013-06-13 2014-12-18 三菱重工業株式会社 インペラ及び流体機械
CN204312394U (zh) * 2014-11-13 2015-05-06 湖南天雁机械有限责任公司 带压气机斜流叶轮的涡轮增压器

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US20170211584A1 (en) 2017-07-27
CN106996391A (zh) 2017-08-01

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