EJECTOR

Abstract

A swirling space in which a refrigerant is swirled into a gas-liquid mixing state includes an upstream swirling space in which the refrigerant flowing from an external is swirled, and a downstream swirling space in which the refrigerant flowing from the upstream swirling space is introduced into a nozzle passage while swirling. Further, a cross-sectional shape of an outlet part of the upstream swirling space is formed into an annular shape along an outer peripheral shape of the upstream swirling space.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2013-103141 filed on May 15, 2013.

TECHNICAL FIELD

The present disclosure relates to an ejector that depressurizes a fluid, and draws the fluid by a suction action of an ejection fluid at high speed.

BACKGROUND ART

Up to now, Patent Document 1 discloses a depressurizing device that is applied to a vapor compression refrigeration cycle device, and depressurizes the refrigerant.

The depressurizing device of Patent Document 1 has a main body that defines a swirling space in which the refrigerant is swirled, and swirls the refrigerant within the swirling space, to thereby reduce a refrigerant pressure on a swirling center side to a pressure at which the refrigerant is depressurized and boiled (cavitation occurs). Further, the depressurizing device allows the refrigerant in a gas-liquid mixing state in which a gas-phase refrigerant and a liquid-phase refrigerant on the swirling center side are mixed together to flow into a minimum passage area part for depressurization.

With the above configuration, in the depressurizing device of Patent Document 1, even if a state of the refrigerant flowing into the swirling space changes due to a change in an outside temperature, a density of the refrigerant flowing into the minimum passage area part is restrained from largely changing to suppress a variation in a flow rate of the refrigerant flowing toward a downstream side of the depressurizing device.

Patent Document 1 also discloses an ejector using the depressurizing device as a nozzle. The ejector of this type draws the gas-phase refrigerant flowing out of the evaporator due to the suction action of the ejected refrigerant ejected from the nozzle, and mixes the ejected refrigerant with the suction refrigerant in a pressure increase part (diffuser portion), thereby being capable of increasing the pressure.

Accordingly, in a refrigeration cycle device (hereinafter referred to as an ejector type refrigeration cycle) including an ejector as a refrigerant depressurization device, power consumption of a compressor can be reduced with the use of a refrigerant pressure increase action in the pressure increase part of an ejector, and a coefficient of performance (COP) of a cycle can be improved to a greater extent than a general refrigeration cycle device including an expansion valve or the like as the refrigerant depressurization device.

Further, in the ejector disclosed in Patent Document 1, as described above, a variation in the ejected refrigerant ejected from the nozzle is suppressed, and the refrigerant in the gas-liquid mixing state is depressurized in the minimum passage area part to promote the boiling of the liquid-phase refrigerant and improve the nozzle efficiency. The nozzle efficiency represents an energy conversion efficiency for converting a pressure energy of the refrigerant into a kinetic energy in the nozzle.

However, in the ejector disclosed in Patent Document 1, when the state of the refrigerant flowing into the swirling space changes due to the change in the outside temperature, the variation in the flow rate of the ejected refrigerant ejected from the nozzle can be suppressed. However, there is a case in which the nozzle efficiency cannot be improved to a desired value depending on an operation condition.

Under the circumstances, the present inventors have searched the cause, and found that in the ejector disclosed in Patent Document 1, the refrigerant flows into a tangential direction of the swirling space circular in cross-section when the refrigerant flows into the swirling space, and this flow makes impossible to improve the nozzle efficiency to the desired value. The reason is because when the refrigerant flows in the tangential direction of the swirling space circular in cross-section, the depressurization and boiling of the refrigerant in the swirling space is limited as will be described later.

When the depressurization and boiling of the refrigerant within the swirling space is limited, a ratio of the gas-phase refrigerant to the refrigerant in the gas-liquid mixing state which flows into the minimum passage area part decreases to reduce boiling nucleus for promoting the boiling of the liquid-phase refrigerant, resulting in a boiling delay of partial liquid-phase refrigerant. As a result, the refrigerant ejected from the minimum passage area part cannot be effectively accelerated, which may cause the nozzle efficiency to be reduced.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: JP 2012-202653 A

SUMMARY OF THE INVENTION

In view of the above, it is an objective of the present disclosure is to limit a reduction in nozzle efficiency of an ejector that depressurizes a fluid which is swirled into a gas-liquid mixing state.

According to a first aspect of the present disclosure, an ejector includes a swirling space formation member having a swirling space in which a fluid is swirled, a nozzle that depressurizes and ejects the fluid flowing out of the swirling space, and a body including a fluid suction port that draws a fluid due to a suction action of the ejected fluid at high speed which is ejected from the nozzle, and a pressure increase part that mixes the ejected fluid with the suction fluid drawn from the fluid suction port and increases a pressure of the mixed fluid. The swirling space includes an upstream swirling space in which the fluid flowing from an external is swirled, and a downstream swirling space that introduces the fluid flowing out of the upstream swirling space into the nozzle with keeping the fluid swirling. The upstream swirling space and the downstream swirling space have respective rotating body shapes in which center axes are disposed coaxially with each other. The upstream swirling space has an outlet part through which the fluid outflows to the downstream swirling space, and the outlet part has an annular shape along an outer peripheral shape of the upstream swirling space in a cross sectional surface perpendicular to the center axis. The downstream swirling space has a circular shape in a cross sectional surface perpendicular to the center axis.

According to the above configuration, the fluid swirls in an upstream swirling space and a downstream swirling space with the result that a fluid pressure in the downstream swirling space on the swirling center side can be reduced to a pressure at which the fluid is depressurized and boiled (cavitation is generated). Further, the fluid in the gas-liquid mixing state where the gas-phase fluid and the liquid-phase fluid in the downstream swirling space on the swirling center side are mixed together is allowed to flow into the nozzle, and can be depressurized. The refrigerant in the gas-liquid mixing state does not mean only the refrigerant in a gas-liquid two-phase state, but includes the refrigerant in a state in which air bubbles are mixed in the refrigerant in a subcooled liquid-phase state.

Further, since a cross-sectional space of an outlet part is formed into an annular shape along an outer peripheral shape of the upstream swirling space, the fluid flowing out of the upstream swirling space can flow from an outer peripheral side of the downstream swirling space in an axial direction.

With the above configuration, the fluid flowing out of the upstream swirling space can be restrained from flowing toward the swirling center side of the downstream swirling space which has a hollow rotating body shape. In addition, the fluid flowing out of the upstream swirling space can merge into a flow of the liquid-phase fluid staying and circulating in the downstream swirling space from the outer peripheral side toward the nozzle.

Therefore, the flow of fluid staying and circulating in the downstream swirling space is not blocked by the fluid flowing from the upstream swirling space into the downstream swirling space, and the ratio of the gas-phase fluid to the fluid in the gas-liquid mixing state flowing into the nozzle can be restrained from being lowered.

As a result, the boiling of the liquid-phase fluid in the nozzle can be promoted, and a reduction in the nozzle efficiency of the ejector can be limited.

According to a second aspect of the present disclosure, an ejector is used for a vapor compression refrigeration cycle device. The ejector includes a body including a refrigerant inlet port, a swirling space in which a refrigerant flowing from the refrigerant inlet port is swirled, a depressurizing space in which the refrigerant flowing out of the swirling space is depressurized, a suction passage that communicates with a downstream side of the depressurizing space in a refrigerant flow and draws a refrigerant from an external, and a pressurizing space in which an ejection refrigerant ejected from the depressurizing space is mixed with a suction refrigerant drawn from the suction passage. The ejector further includes a passage formation member that includes at least a portion disposed inside the depressurizing space, and a portion disposed inside the pressurizing space, and the passage formation member has a conical shape which increases in cross-sectional area in a direction away from the depressurizing space. A refrigerant passage provided between an inner peripheral surface of the body defining the depressurizing space and an outer peripheral surface of the passage formation member is a nozzle passage functioning as a nozzle that depressurizes and ejects the refrigerant flowing out of the swirling space. A refrigerant passage provided between an inner peripheral surface of the body defining the pressurizing space and an outer peripheral surface of the passage formation member is a diffuser passage functioning as a diffuser that mixes and pressurizes the ejection refrigerant and the suction refrigerant. The swirling space includes an upstream swirling space in which the refrigerant flowing from an external is swirled, and a downstream swirling space in which the refrigerant flowing out of the upstream swirling space is introduced into the nozzle passage with swirling. The upstream swirling space and the downstream swirling space have respective rotating body shapes in which center axes are disposed coaxially with each other. The upstream swirling space has an outlet part through which the refrigerant outflow to the downstream swirling space, and the outlet part has an annular shape along an outer peripheral shape of the upstream swirling space in a cross sectional surface perpendicular to the center axis. The downstream swirling space has a circular shape in a cross sectional surface perpendicular to the center axis.

According to the above configuration, as in the above first aspect, the refrigerant in the gas-liquid mixing state where the gas-phase refrigerant and the liquid-phase refrigerant in the downstream swirling space on the swirling center side are mixed together is allowed to flow into the nozzle passage, and can be depressurized. Further, the refrigerant flowing out of the upstream swirling space can merge into the flow of the liquid-phase refrigerant staying and circulating in the downstream swirling space from the outer peripheral side toward the nozzle passage.

Therefore, the flow of refrigerant staying and circulating in the downstream swirling space is not blocked by the refrigerant flowing from the upstream swirling space into the downstream swirling space, and the ratio of the gas-phase refrigerant to the refrigerant in the gas-liquid mixing state flowing into the nozzle passage can be restrained from being lowered.

As a result, boiling of the liquid-phase refrigerant in the nozzle passage can be promoted, and a reduction in energy conversion efficiency (corresponding to the nozzle efficiency) when the pressure energy of the refrigerant is converted into a velocity energy can be limited in the nozzle passage of the ejector.

The passage formation member is not strictly limited to one having only the shape in which the sectional area increases with distance from the depressurizing space. At least a part of the passage formation member may include a shape in which the sectional area expands with distance from the depressurizing space whereby the diffuser passage has a shape expanding outward with distance from the depressurizing space.

Further, “formed into a conical shape” is not limited to a meaning that the passage formation member is formed into a complete conical shape, but includes a shape similar to a cone, a shape partially including the conical shape, or a shape combining the conical shape, a cylindrical shape, or a truncated conical shape. Specifically, a sectional shape in an axial direction is not limited to an isosceles triangle, and may include a shape that has two sides in a state where an apex is interposed between two sides that are convex toward the inner circumferential side, a shape that has two sides in a state where an apex is interposed between two sides that are convex toward the outer peripheral side, a shape in which the sectional shape is formed in a semicircular shape, or the like.

The “rotating body shape” means a solid shape formed by rotating a plane figure around one straight line (center axis) extending on the same plane.

Further, “annular shape” along the outer peripheral shape of the upstream swirling space does not mean only a “complete annular shape”, but means a shape that is formed into a “substantially annular shape” even if the outlet part is divided by a connection part of a member forming the outlet part. Therefore, the annular shape may be configured by combination of two semicircular shapes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an ejector refrigeration cycle according to a first embodiment of the present disclosure.

FIG. 2 is a cross-sectional view along an axis direction of an ejector according to the first embodiment.

FIG. 3 is a schematic cross-sectional view illustrating a function of each refrigerant passage of the ejector of the first embodiment.

FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 3.

FIG. 5 is a Mollier diagram illustrating a state of a refrigerant in the ejector refrigeration cycle according to the first embodiment.

FIG. 6 is a cross-sectional view along an axial direction of an ejector according to a second embodiment of the present disclosure.

FIG. 7 is a schematic cross-sectional view illustrating a function of each refrigerant passage of the ejector of the second embodiment.

FIG. 8 is a cross-sectional view taken along a line VIII-VIII of FIG. 6.

FIG. 9 is a schematic view illustrating an ejector refrigeration cycle according to a third embodiment of the present disclosure.

FIG. 10 is a cross-sectional view along an axis direction of an ejector according to the third embodiment.

FIG. 11 is a schematic cross-sectional view illustrating a flow of a refrigerant within a swirling space of a depressurizing device in results of simulation analysis by the present inventors.

EMBODIMENTS FOR EXPLOITATION OF THE INVENTION

Hereinafter, multiple embodiments for implementing the present invention will be described referring to drawings. In the respective embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

First Embodiment

A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 5. As illustrated in an overall configuration diagram of FIG. 1, an ejector 13 according to this embodiment is applied to a refrigeration cycle device having an ejector as a refrigerant depressurizing device, that is, an ejector refrigeration cycle 10. Moreover, the ejector refrigeration cycle 10 is applied to a vehicle air conditioning apparatus, and performs a function of cooling a blast air which is blown into a vehicle interior that is a space to be air-conditioned.

In addition, an HFC-based refrigerant (more specifically, R134a) is applied as the refrigerant in the ejector refrigeration cycle 10, and a vapor compression type subcritical refrigeration cycle in which high pressure-side refrigerant pressure does not exceed critical pressure of the refrigerant is configured. It is needless to say that an HFO-based refrigerant (for example, R1234yf) may be employed as the refrigerant. Furthermore, refrigerator oil for lubricating a compressor 11 is mixed in the refrigerant, and a part of the refrigerator oil circulates in the cycle together with the refrigerant.

In the ejector type refrigeration cycle 10, the compressor 11 draws the refrigerant, increases the pressure of the refrigerant until the refrigerant becomes a high-pressure refrigerant, and discharges the pressurized refrigerant. Specifically, the compressor 11 of this embodiment is an electric compressor that is configured to accommodate a fixed capacity type compression mechanism 11a and an electric motor 11b for driving the compression mechanism 11a in a single housing.

As the compression mechanism 11a, various compression mechanisms such as a scroll compression mechanism or a vane compression mechanism are capable of being adopted. The electric motor 11b controls an operation (rotation speed) of the electric motor according to control signals output from a control device to be described below, and any motor of an AC motor and a DC motor may be applied.

The compressor 11 may be an engine driven compressor that is driven by a rotation driving force transmitted via a pulley, a belt, or the like from a vehicle travel engine. As the engine driven compressor of this type, a variable capacity compressor that can adjust a refrigerant discharge capacity by a change in discharge capacity, or a fixed capacity type compressor that adjusts the refrigerant discharging capacity by changing an operation rate of the compressor through connection/disconnection of an electromagnetic clutch can be applied.

A refrigerant inlet side of a condenser 12a of a radiator 12 is connected to a discharge port side of the compressor 11. The radiator 12 is a radiation heat exchanger which performs heat exchange between a high pressure refrigerant discharged from the compressor 11 and a vehicle exterior air (outside air) blown by a cooling fan 12d to radiate the heat of the high pressure refrigerant for cooling.

More specifically, the heat radiator 12 is a so-called subcooling condenser including: the condenser 12a, a receiver part 12b, and a subcooling portion 12c. The condenser 12a performs heat exchange between the high pressure gas-phase refrigerant discharged from the compressor 11 and the outside air blown from the cooling fan 12d, and radiates the heat of the high pressure gas-phase refrigerant to condense the refrigerant. The receiver part 12b separates gas and liquid of the refrigerant flowing out of the condenser 12a and stores a surplus liquid-phase refrigerant. The subcooling portion 12c performs heat exchange between the liquid-phase refrigerant flowing out of the receiver part 12b and the outside air blown from the cooling fan 12d to subcool the liquid-phase refrigerant.

The cooling fan 12d is an electric blower of which the rotating speed (the amount of blast air) is controlled by a control voltage output from the control device. A refrigerant inlet port 31a of the ejector 13 is connected to a refrigerant outlet side of the subcooling portion 12c of the heat radiator 12.

The ejector 13 functions as a refrigerant depressurizing device for depressurizing the high pressure liquid-phase refrigerant (fluid) of the subcooling state, which flows out of the heat radiator 12, and allowing the refrigerant to flow out to the downstream side. The ejector 13 also functions as a refrigerant circulating device (refrigerant transport device) for drawing (transporting) the refrigerant (fluid) flowing out of an evaporator 14 to be described later by the suction action of the refrigerant (fluid) ejected at high speed to circulate the refrigerant. Further, the ejector 13 according to this embodiment also functions as a gas-liquid separation device for separating the depressurized refrigerant into gas and liquid.

A specific configuration of the ejector 13 will be described with reference to FIGS. 2 to 4. Meanwhile, up and down arrows in FIG. 2 indicate, respectively, up and down directions in a state where the ejector refrigeration cycle 10 is mounted on a vehicle air conditioning apparatus. Also, FIGS. 3 and 4 are schematic cross-sectional views illustrating functions and shapes of the respective refrigerant passages of the ejector 13, and the same parts as those in FIG. 2 are denoted by identical symbols.

First, as illustrated in FIG. 2, the ejector 13 according to this embodiment includes a body 30 configured by the combination of plural components. Specifically, the body 30 has a housing body 31 made of prismatic-cylindrical or circular-cylindrical metal or resin, and forming an outer shell of the ejector 13. A nozzle body 32, a middle body 33, and a lower body 34 are fixed to an interior of the housing body 31.

The housing body 31 is formed with a refrigerant inlet port 31a, a refrigerant suction port 31b, a liquid-phase refrigerant outlet port 31c, and a gas-phase refrigerant outlet port 31d. The refrigerant inlet port 31a allows the refrigerant flowed out of the heat radiator 12 to flow into the body 30. The refrigerant suction port 31b is configured to draw the refrigerant flowing out of the evaporator 14. The liquid-phase refrigerant outlet port 31c allows a liquid-phase refrigerant separated by a gas-liquid separation space 30f formed within the body 30 to flow out to the refrigerant inlet side of the evaporator 14. The gas-phase refrigerant outlet port 31d allows the gas-phase refrigerant separated by the gas-liquid separation space 30f to flow out to the intake side of the compressor 11.

The refrigerant inlet port 31a is opened in the center of an upper surface of the housing body 31. Further, a refrigerant inflow passage 31e for introducing the refrigerant into the interior of the body 30 from the refrigerant inlet port 31a is formed into a cylindrical shape having a center axis extended in a vertical direction (vertical direction in FIG. 2). Further, the refrigerant inflow passage 31e introduces the refrigerant flowing from the refrigerant inlet port 31a into a space formed within the nozzle body 32. In FIGS. 2 and 3, the center axis of the refrigerant inflow passage 31e is indicated by a dashed line.

The nozzle body 32 is formed of a substantially conical metal member tapered toward a refrigerant flow direction, and a part of a swirling space 30a for swirling the refrigerant and a depressurizing space 30b for depressurizing the refrigerant flowing out of the swirling space 30a are defined in the interior of the nozzle body 32. The part of the swirling space 30a and the depressurizing space 30b are formed into a rotating body shape by combination of a cylindrical shape and a truncated conical shape.

Further, the nozzle body 32 is fixed to the interior of the housing body 31 by press fitting so that the center axis of the space defined in the interior of the nozzle body 32 is disposed coaxially with the center axis of the refrigerant inflow passage 31e.

A swirling promotion member 38 that swirls the refrigerant flowing from the refrigerant inlet port 31a around the center axis of the refrigerant inflow passage 31e is fixed in the interior of the refrigerant inflow passage 31e. The swirling promotion member 38 includes an upper plate 38a and a lower plate 38b which are each formed into a disc shape, and whose plate surfaces are disposed in parallel to each other, and multiple flow regulating plates 38c disposed between those plates 38a and 38b.

The upper plate 38a forms a fixing portion for fixing the swirling promotion member 38 to the interior of the refrigerant inflow passage 31e. Specifically, an outer peripheral side surface of the upper plate 38a is press-fitted into an inner peripheral wall surface of the refrigerant inflow passage 31e. A through-hole that penetrates through front and rear sides of the upper plate 38a is defined in the center of the upper plate 38a, and the through-hole configures an inlet part 38d for allowing the refrigerant flowing from the refrigerant inlet port 31a to flow toward the nozzle body 32 side.

As illustrated in FIG. 4, an outer diameter of the lower plate 38b is formed to be smaller than an inner diameter of the refrigerant inflow passage 31e. Therefore, a gap formed into an annular shape when viewed from the axial direction of the refrigerant inflow passage 31e is defined between an outer peripheral side of the lower plate 38b and an inner peripheral wall surface of the refrigerant inflow passage 31e. The annular gap configures an outlet part 38e for allowing the refrigerant flowing into the space between the upper plate 38a and the lower plate 38b to flow toward the nozzle body 32 side. No through-hole is defined in the lower plate 38b.

As illustrated in FIG. 4, the multiple flow regulating plates 38c are arranged in an annular shape around the center axis of the refrigerant inflow passage 31e. Further, the plate surfaces of the respective flow regulating plates 38c are so tilted or curved as to swirl a flow of the refrigerant around the center axis when viewed from the center axis direction.

Therefore, the refrigerant flowing into the refrigerant inflow passage 31e from the refrigerant inlet port 31a flows into the space between the upper plate 38a and the lower plate 38b through the inlet part 38d of the upper plate 38a. The refrigerant flowing into the space between the upper plate 38a and the lower plate 38b flows from the center axis radially outward within the space. In this situation, the refrigerant flows along the plate surfaces of the flow regulating plates 38c whereby the refrigerant swirls around the center axis.

The refrigerant that reaches an outer peripheral side of the space between the upper plate 38a and the lower plate 38b flows into a space below (downstream of) the lower plate 38b from the outlet part 38e formed in the outer peripheral side of the lower plate 38b while swirling around the center axis. Further, the refrigerant that flows into the space below (downstream of) the lower plate 38b is introduced into a nozzle passage 13a side to be described later while swirling around the center axis.

As is apparent from the above description, as illustrated in FIG. 3, the swirling promotion member 38 according to this embodiment (specifically, the upper plate 38a) partitions the swirling space 30a below (downstream of) the swirling promotion member 38. Further, the space defined between the upper plate 38a and the lower plate 38b in the interior of the swirling promotion member 38 is an example of an upstream swirling space 301 in which the refrigerant flowing from an external swirls.

The outlet part 38e for allowing the refrigerant to flow out of the space (upstream swirling space 301) defined between the upper plate 38a and the lower plate 38b is formed into the inner peripheral shape of the refrigerant inflow passage 31e in a cross-sectional surface perpendicular to the axial direction of the upstream swirling space 301, that is, an annular shape along the outer peripheral shape of the upstream swirling space 301.

Further, the swirling space 30a below (downstream of) the lower plate 38b is an example of a downstream swirling space 302 for introducing the refrigerant flowing out of the upstream swirling space 301 toward the depressurizing space 30b side while swirling.

In this example, the swirling space 30a (downstream swirling space 302) below the lower plate 38b is formed into a hollow rotating body shape, that is, a circular shape in a cross-sectional surface perpendicular to the axial direction of the refrigerant inflow passage 31e. Therefore, in the downstream swirling space 302, a refrigerant pressure on the center axis side is reduced more than the refrigerant pressure on the outer peripheral side due to the action of a centrifugal force generated by swirling the refrigerant.

Under the circumstances, in this embodiment, at the time of a normal operation of the ejector refrigeration cycle 10, the refrigerant pressure on the center axis side in the downstream swirling space 302 decreases down to a pressure at which the refrigerant is depressurized and boiled (cavitation is generated). The refrigerant pressure on the center axis side within the downstream swirling space 302 as described above can be adjusted by adjustment of the number or the tilt angle of flow regulating plates 38c, or by adjustment of the layout of the flow regulating plates 38c (for example, speed increasing cascade arrangement).

The depressurizing space 30b is defined below the swirling space 30a (specifically, downstream swirling space 302) in the space defined in the nozzle body 32. The depressurizing space 30b is formed into a rotating body into which the cylindrical space is coupled with a truncated conical space that gradually spreads toward the refrigerant flow direction continuously from a lower side of the cylindrical space.

Further, a passage formation member 35 is disposed in the interior of the depressurizing space 30b. The passage formation member 35 forms a minimum passage area part 30m smallest in the refrigerant passage area within the depressurizing space 30b, and changes the passage area of the minimum passage area part 30m. The passage formation member 35 is formed in an approximately conical shape which gradually spreads toward a downstream side in a refrigerant flow, and a center axis of the passage formation member 35 is disposed coaxially with the center axis of the refrigerant inflow passage 31e. In other words, the passage formation member 35 is formed into a conical shape having a cross-sectional area increased with distance from the depressurizing space 30b.

The refrigerant passage is formed between an inner peripheral surface of a portion of the nozzle body 32 which defines the depressurizing space 30b and an outer peripheral surface of the upper side of the passage formation member 35. As illustrated in FIG. 3, the refrigerant passage includes a convergent part 131 and a divergent part 132. The convergent part 131 is formed on the upstream side of the minimum passage area part 30m in the refrigerant flow, in which the refrigerant passage area extending to the minimum passage area part 30m gradually decreases. The divergent part 132 is formed on the downstream side of the minimum passage area part 30m in the refrigerant flow, in which the refrigerant passage area gradually increases.

In the convergent part 131 and the divergent part 132, since the depressurizing space 30b overlaps with the passage formation member 35 when viewed from the radial direction, a sectional shape of the refrigerant passage perpendicular to the axis direction is annular (doughnut shape obtained by removing a smaller-diameter circular shape arranged coaxially from the circular shape). Further, since a spread angle of the passage formation member 35 of this embodiment is smaller than a spread angle of the circular truncated conical space of the depressurizing space 30b, the refrigerant passage area of the divergent part 132 gradually enlarges toward the downstream side in the refrigerant flow.

In this embodiment, the refrigerant passage defined between the inner peripheral surface of the depressurizing space 30b and the outer peripheral surface of a top side of the passage formation member 35 is a nozzle passage 13a that functions as a nozzle by the passage shape. In the nozzle passage 13a, the refrigerant is depressurized, and accelerated and ejected in a state where a flow rate of the refrigerant in the gas-liquid mixing state becomes higher than a two-phase sound velocity.

Since the refrigerant flowing into the nozzle passage 13a swirls in the swirling space 30a (specifically, downstream swirling space 302), the refrigerant flowing through the nozzle passage 13a, and the ejected refrigerant that is ejected from the nozzle passage 13a also have a velocity component in a direction of swirling in the same direction as that of the refrigerant swirling in the swirling space 30a (upstream swirling space 301 and downstream swirling space 302).

Next, as illustrated in FIG. 2, the middle body 33 is formed of a disc-shaped member made of metal which defines a through-hole of the rotating body shape which penetrates through both sides thereof in the center of the middle body 33. The middle body 33 accommodates a driving device 37 on an outer peripheral side of the through-hole, and the driving device 37 displaces the passage formation member 35. Meanwhile, a center axis of the through-hole is arranged coaxially with the center axes of the refrigerant inflow passage 31e and the passage formation member 35. The middle body 33 is fixed to the interior of the housing body 31 and the lower side of the nozzle body 32 by press fitting.

An inflow space 30c is provided between an upper surface of the middle body 33 and an inner wall surface of the housing body 31 facing the middle body 33, and the inflow space 30c accumulates the refrigerant flowing from the refrigerant suction port 31b. Meanwhile, in this embodiment, because a tapered tip of a lower side of the nozzle body 32 is located within the through-hole of the middle body 33, the inflow space 30c is formed into an annular shape in cross-section when viewed from the center axis direction of the refrigerant inflow passage 31e and the passage formation member 35.

A suction refrigerant inflow passage connecting the refrigerant suction port 31b and the inflow space 30c extends in a tangential direction of the inner peripheral wall surface of the inflow space 30c when viewed from the center axis direction of the inflow space 30c. With the above configuration, in this embodiment, the refrigerant flowing into the inflow space 30c from the refrigerant suction port 31b through the suction refrigerant inflow passage is swirled in the same direction as that of the refrigerant in the swirling space 30a (upstream swirling space 301 and downstream swirling space 302).

The through-hole of the middle body 33 has a part in which a refrigerant passage area is gradually reduced toward the refrigerant flow direction so as to match an outer peripheral shape of the tapered tip of the nozzle body 32 in an area where the lower side of the nozzle body 32 is inserted, that is, an area in which the middle body 33 and the nozzle body 32 overlap with each other when viewed in a radial direction perpendicular to the axis line.

Accordingly, a suction passage 30d is defined between an inner peripheral surface of the through-hole and an outer peripheral surface of the lower side of the nozzle body 32, and the inflow space 30c communicates with a downstream side of the depressurizing space 30b in the refrigerant flow through the suction passage 30d. That is, in this embodiment, a suction passage 13b that draws the refrigerant from the external is defined by the inflow space 30c, and the suction passage 30d. Further, a cross-section perpendicular to the center axis of the suction passage 13b is also formed into an annular shape, and the drawn refrigerant flows in the suction passage 13b from the outer peripheral side toward the inner peripheral side of the center axis while swirling.

A pressurizing space 30e formed into a substantially circular truncated conical shape that gradually spreads in the refrigerant flow direction is formed in the through-hole of the middle body 33 on the downstream side of the suction passage 30d in the refrigerant flow. The pressurizing space 30e is a space in which the ejected refrigerant ejected from the above-mentioned nozzle passage 13a is mixed with the suction refrigerant drawn from the suction passage 30d.

The lower side of the above-mentioned passage formation member 35 is located in the interior of the pressurizing space 30e. Further, a spread angle of the conical-shaped side surface of the passage formation member 35 in the pressurizing space 30e is smaller than a spread angle of the circular truncated conical space of the pressurizing space 30e. Therefore, the refrigerant passage area of the refrigerant passage is gradually enlarged toward the downstream side in the refrigerant flow.

In this embodiment, the refrigerant passage area is enlarged as above. Thus, the refrigerant passage, which is formed between the inner peripheral surface of the middle body 33 and the outer peripheral surface of the lower side of the passage formation member 35 and configures the pressurizing space 30e, is defined as a diffuser passage 13c which functions as a diffuser. The diffuser passage 13c converts velocity energies of a mixed refrigerant of the ejection refrigerant and the suction refrigerant into a pressure energy. That is, in the diffuser passage 13c, the ejection refrigerant and the suction refrigerant are mixed together, and pressurized. The cross-sectional shape perpendicular to the center axis of the diffuser passage 13c is also formed into an annular shape.

The refrigerant ejected from the nozzle passage 13a toward the diffuser passage 13c side and the refrigerant drawn from the suction passage 13b have a velocity component in the same swirling direction as that of the refrigerant swirling in the swirling space 30a (upstream swirling space 301 and downstream swirling space 302). Therefore, the refrigerant flowing in the diffuser passage 13c and the refrigerant flowing out of the diffuser passage 13c also have a velocity component in the same swirling direction as that of the refrigerant swirling in the swirling space 30a (upstream swirling space 301 and downstream swirling space 302).

Next, the driving device 37 that is arranged within the middle body 33 and displaces the passage formation member 35 will be described. The driving device 37 is configured with a circular laminated diaphragm 37a which is a pressure responsive member. More specifically, as illustrated in FIG. 2, the diaphragm 37a is fixed by welding so as to partition a cylindrical space defined on the outer peripheral side of the middle body 33 into two upper and lower spaces.

The upper space (the inflow space 30c side) of the two spaces partitioned by the diaphragm 37a configures a sealed space 37b in which a temperature sensitive medium is enclosed. A pressure of the temperature sensitive medium changes according to a temperature of the refrigerant flowing out of the evaporator 14. A temperature sensitive medium having the same composition as that of the refrigerant circulating through the ejector type refrigeration cycle 10 is sealed in the sealed space 37b at predetermined density. Accordingly, the temperature sensitive medium of this embodiment is R134a.

On the other hand, the lower space of the two spaces partitioned by the diaphragm 37a configures an introduction space 37c into which the refrigerant flowing out of the evaporator 14 is introduced through a non-shown communication channel. Therefore, the temperature of the refrigerant flowing out of the evaporator 14 is transmitted to the temperature sensitive medium enclosed in the sealed space 37b via a cap member 37d and the diaphragm 37a that partition the inflow space 30c and the sealed space 37b.

In this example, as apparent from FIGS. 2 and 3, the suction passage 13b is arranged on the upper side of the middle body 33 in this embodiment, and the diffuser passage 13c is arranged on the lower side of the middle body 33. Therefore, at least a part of the driving device 37 is arranged at a position sandwiched by the suction passage 13b and the diffuser passage 13c from the vertical direction when viewed from the radial direction of the axis line.

In more detail, the sealed space 37b of the driving device 37 is arranged at a position where the suction passage 13b overlaps with the diffuser passage 13c and at a position surrounded by the suction passage 13b and the diffuser passage 13c when viewed from a center axis direction of the refrigerant inflow passage 31e and the passage formation member 35. Accordingly, the temperature of the refrigerant flowing out from the evaporator 14 is transmitted to the sealed space 37b, and an inner pressure in the sealed space 37b becomes a pressure corresponding to the temperature of the refrigerant flowing out from the evaporator 14.

Further, the diaphragm 37a is deformed according to a differential pressure between the internal pressure of the sealed space 37b and the pressure of the refrigerant which has flowed into the introduction space 37c from the evaporator 14. For that reason, it is preferable that the diaphragm 37a is made of a material rich in elasticity, excellent in heat conduction, and tough. For example, it is desirable that the diaphragm 37a is formed of a metal laminate made of stainless steel (SUS304).

An upper end side of a cylindrical actuating bar 37e is joined to a center part of the diaphragm 37a by welding, and a lower end side of the actuating bar 37e is fixed to an outer peripheral side of the lowermost side (bottom side) of the passage formation member 35. With this configuration, the diaphragm 37a and the passage formation member 35 are coupled with each other, and the passage formation member 35 is displaced in accordance with a displacement of the diaphragm 37a to regulate the refrigerant passage area of the nozzle passage 13a (passage cross-sectional area in the minimum passage area part 30m).

Specifically, when the temperature (the degree of superheat) of the refrigerant following out of the evaporator 14 rises, a saturated pressure of the temperature sensitive medium enclosed in the sealed space 37b rises to increase a differential pressure obtained by subtracting the pressure of the introduction space 37c from the internal pressure of the sealed space 37b. Accordingly, the diaphragm 37a displaces the passage formation member 35 in a direction of enlarging the passage cross-sectional area in the minimum passage area part 30m (downward in the vertical direction).

On the other hand, when the temperature (the degree of superheat) of the refrigerant flowing out of the evaporator 14 falls, a saturated pressure of the temperature sensitive medium sealed in the sealed space 37b falls to decrease the differential pressure obtained by subtracting the pressure of the introduction space 37c from the internal pressure of the sealed space 37b. With the above configuration, the diaphragm 37a displaces the passage formation member 35 in a direction of reducing the passage cross-sectional area of the minimum passage area part 30m (toward the upper side in the vertical direction).

The diaphragm 37a displaces the passage formation member 35 vertically according to the superheat of the refrigerant flowing out of the evaporator 14 as described above. As a result, the passage cross-sectional area of the minimum passage area part 30m is adjusted so that the degree of superheat of the refrigerant flowing out of the evaporator 14 comes closer to a predetermined value. A gap between the actuating bar 37e and the middle body 33 is sealed by a seal member such as an O-ring not shown, and the refrigerant is not leaked through the gap even if the actuating bar 37e is displaced.

The bottom of the passage formation member 35 is subjected to a load of a coil spring 40 fixed to the lower body 34. The coil spring 40 exerts the load urging the passage formation member 35 so as to reduce the passage cross-sectional area in the minimum passage area part 30m (upper side in FIG. 2). With the regulation of this load, a valve opening pressure of the passage formation member 35 can be changed to change a target degree of superheat.

Incidentally, in this embodiment, the multiple (specifically, two as illustrated in FIGS. 2 and 3) cylindrical spaces are provided in the part of the middle body 33 on the radially outer side, and the respective circular laminated diaphragms 37a are fixed in those spaces to configure two driving devices 37. However, the number of driving devices 37 is not limited to this number. When the driving devices 37 are provided at plural locations, it is desirable that the driving devices 37 are arranged at regular angular intervals with respect to the respective center axes.

Alternatively, a diaphragm formed of the annular thin plate may be fixed in a space having an annular shape when viewed from the center axis direction, and the diaphragm and the passage formation member 35 may be coupled with each other by multiple actuating bars.

Next, the lower body 34 is formed of a circular-cylindrical metal member, and fixed in the housing body 31 by screwing so as to close a bottom of the housing body 31. As illustrated in FIGS. 2 and 3, the gas-liquid separation space 30f that separates gas and liquid of the refrigerant that has flowed out of the above-mentioned diffuser passage 13c from each other is defined between the upper side of the lower body 34 and the middle body 33.

The gas-liquid separation space 30f is defined as a space of a substantially cylindrical rotating body shape, and the center axis of the gas-liquid separation space 30f is also arranged coaxially with the center axes of the refrigerant inflow passage 31e and the passage formation member 35.

As described above, the refrigerant, which flows out from the diffuser passage 13c and flows into the gas-liquid separation space 30f, has the velocity component of the refrigerant swirling in the same direction as the swirl direction of the refrigerant swirling in the swirling space 30a (upstream swirling space 301 and downstream swirling space 302). Accordingly, gas and liquid of the refrigerant in the gas-liquid separation space 30f are separated by action of a centrifugal force.

A hollow cylindrical pipe 34a that is arranged coaxially with the gas-liquid separation space 30f and extends upward is disposed in the center part of the lower body 34. The liquid-phase refrigerant separated in the gas-liquid separation space 30f is accumulated on a radially outer side of the pipe 34a. Also, a gas-phase refrigerant outflow passage 34b is formed inside the pipe 34a and guides the gas-phase refrigerant separated in the gas-liquid separation space 30f to the gas-phase refrigerant outlet port 31d of the housing body 31.

Further, the above-mentioned coil spring 40 is fixed to an upper end of the pipe 34a. The coil spring 40 also functions as a vibration absorbing member that attenuates the vibration of the passage formation member 35, which is caused by a pressure pulsation generated when the refrigerant is depressurized. An oil return hole 34c that returns a refrigerator oil in the liquid-phase refrigerant into the compressor 11 through the gas-phase refrigerant outflow passage 34b is formed on a base part (lowermost part) of the pipe 34a.

The liquid-phase refrigerant outlet port 31c of the ejector 13 is connected with an inlet side of the evaporator 14 as illustrated in FIG. 1. The evaporator 14 is a heat-absorbing heat exchanger that evaporates a low-pressure refrigerant depressurized by the ejector 13 and performs a heat absorbing effect by exchanging heat between the low-pressure refrigerant and blast air that is blown into the vehicle interior from a blower fan 14a.

The blower fan 14a is an electric blower of which the rotation speed (the amount of blast air) is controlled by a control voltage output from the control device. The refrigerant suction port 31b of the ejector 13 is connected to an outlet side of the evaporator 14. Further, the gas-phase refrigerant outlet port 31d of the ejector 13 is connected with the intake side of the compressor 11.

Next, the control device (not shown) includes a well-known microcomputer including a CPU, a ROM and a RAM, and peripheral circuits of the microcomputer. The control device controls the operations of the above-mentioned various electric actuators 11b, 12d, and 14a and the like by performing various calculations and processing on the basis of a control program stored in the ROM.

Further, an air conditioning control sensor group such as an inside air temperature sensor for detecting a vehicle interior temperature, an outside air temperature sensor for detecting the temperature of outside air, an insolation sensor for detecting the amount of insolation in the vehicle interior, an evaporator-temperature sensor for detecting the blow-out air temperature from the evaporator 14 (the temperature of the evaporator), an outlet-side temperature sensor for detecting the temperature of a refrigerant on the outlet side of the heat radiator 12, and an outlet-side pressure sensor for detecting the pressure of a refrigerant on the outlet side of the heat radiator 12, is connected to the control device. Accordingly, detection values of the sensor group are input to the control device.

Furthermore, an operation panel (not shown), which is disposed near a dashboard panel positioned at the front part in the vehicle interior, is connected to the input side of the control device, and operation signals output from various operation switches mounted on the operation panel are input to the control device. An air conditioning operation switch that is used to perform air conditioning in the vehicle interior, a vehicle interior temperature setting switch that is used to set the temperature of the vehicle interior, and the like are provided as the various operation switches that are mounted on the operation panel.

Meanwhile, the control device of this embodiment is integrated with a control unit for controlling the operations of various control target devices connected to the output side of the control device, but a structure (hardware and software), which controls the operations of the respective control target devices, of the control device forms the control unit of the respective control target devices. For example, a structure (hardware and software), which controls the operation of the electric motor 11b of the compressor 11, forms a discharge capability control unit in this embodiment.

Next, the operation of this embodiment having the above-mentioned configuration will be described with reference to a Mollier diagram of FIG. 5. A vertical axis of the Mollier diagram indicates pressures corresponding to P0, P1, and P2 of FIG. 3. First, when an operation switch of an operation panel is turned on, the control device operates the electric motor 11b of the compressor 11, the cooling fan 12d, the blower fan 14a, or the like. Accordingly, the compressor 11 draws and compresses a refrigerant and discharges the refrigerant.

The gas-phase refrigerant (point a5 in FIG. 5), which is discharged from the compressor 11 and has a high temperature and a high pressure, flows into the condenser 12a of the heat radiator 12 and is condensed by exchanging heat between the blast air (outside air), which is blown from the cooling fan 12d, and itself and by radiating heat. Gas and liquid of the refrigerant radiated by the condenser 12a are separated by the receiver part 12b. A liquid-phase refrigerant, which has been subjected to gas-liquid separation in the receiver part 12b, is changed into a subcooled liquid-phase refrigerant by exchanging heat between the blast air, which is blown from the cooling fan 12d, and itself in the subcooling portion 12c and further radiating heat (from point a5 to point b5 in FIG. 5).

The subcooled liquid-phase refrigerant that has flowed out of the subcooling portion 12c of the heat radiator 12 is isentropically depressurized by the nozzle passage 13a, and ejected (from point b5 to point c5 in FIG. 5). The nozzle passage 13a is formed between the inner peripheral surface of the depressurizing space 30b of the ejector 13 and the outer peripheral surface of the passage formation member 35. In this situation, the refrigerant passage area in the minimum passage area part 30m of the depressurizing space 30b is regulated so that the degree of superheat of the refrigerant on the outlet side of the evaporator 14 comes close to a predetermined given value.

The refrigerant that has flowed out of the evaporator 14 is drawn through the refrigerant suction port 31b and the suction passage 13b (in more detail, the inflow space 30c and the suction passage 30d) due to the suction action of the ejection refrigerant which has been ejected from the nozzle passage 13a. In addition, the ejection refrigerant ejected from the nozzle passage 13a and the suction refrigerant drawn through the suction passage 13b and the like flow into the diffuser passage 13c (from point c5 to point d5, and from point h5 to point d5 in FIG. 5).

In the diffuser passage 13c, the velocity energy of the refrigerant is converted into the pressure energy due to the enlarged refrigerant passage area. As a result, the mixed refrigerant is pressurized while the ejection refrigerant and the suction refrigerant are mixed together (from point d5 to point e5 in FIG. 5). The refrigerant that has flowed out of the diffuser passage 13c is separated into gas and liquid in the gas-liquid separation space 30f (from point e5 to point f5, and from point e5 to point g5 in FIG. 5).

The liquid-phase refrigerant that has been separated in the gas-liquid separation space 30f flows out of the liquid-phase refrigerant outlet port 31c, and flows into the evaporator 14. The refrigerant which has flowed into the evaporator 14 absorbs heat from blown air blown by the blower fan 14a, is evaporated, and cools the blast air (point g5 to point h5 in FIG. 5). On the other hand, the gas-phase refrigerant that has been separated in the gas-liquid separation space 30f flows out of the gas-phase refrigerant outlet port 31d, and is drawn into the compressor 11 and compressed again (point f5 to point a5 in FIG. 5).

The ejector refrigeration cycle 10 according to this embodiment operates as described above, and can cool the blast air to be blown into the vehicle interior. Further, in the ejector refrigeration cycle 10, since the refrigerant pressurized by the diffuser passage 13c is drawn into the compressor 11, the drive power of the compressor 11 can be reduced to improve the cycle of performance (COP).

According to the ejector 13 of this embodiment, the fluid swirls in the upstream swirling space 301 and the downstream swirling space 302 with the result that a fluid pressure in the downstream swirling space 302 on the swirling center side can be reduced to a pressure at which the refrigerant is depressurized and boiled (cavitation is generated). Further, the refrigerant in the gas-liquid mixing state where the gas-phase refrigerant and the liquid-phase refrigerant in the downstream swirling space 302 on the swirling center side are mixed together is allowed to flow into the nozzle passage 13a, and can be depressurized.

Therefore, even a state of the refrigerant flowing into the swirling space 30a (specifically, the upstream swirling space 301) changes due to a change in the outside temperature, the density of the refrigerant flowing into the nozzle passage 13a is restrained from largely changing, and a variation in the flow rate of the ejected refrigerant ejected from the nozzle passage 13a can be suppressed.

According to the configuration of the nozzle passage 13a of the ejector 13 of this embodiment, a state of the refrigerant in the vicinity of the minimum passage area part 30m approaches the gas-liquid mixing state in which the gas-phase refrigerant and the liquid-phase refrigerant are homogeneously mixed together, and blocking (choking) is generated in a flow of the refrigerant of the gas-liquid mixing state. As a result, the flow rate of the refrigerant can be accelerated to the sound velocity or higher.

Further, the refrigerant in the gas-liquid mixing state which is a supersonic state flows into the divergent portion 132 so as to be further accelerated and ejected. Therefore, the effective improvement in the energy conversion efficiency in converting the pressure energy of the refrigerant into the velocity energy in the nozzle passage 13a can be expected.

However, when a boiling delay is generated in the liquid-phase refrigerant flowing into the nozzle passage 13a, a flow of the refrigerant cannot be choked in the vicinity of the minimum passage area part 30m of the nozzle passage 13a, the energy conversion efficiency in the nozzle passage 13a may be lowered.

On the contrary, in the ejector 13 of this embodiment, since the sectional shape of the outlet part 38e for allowing the refrigerant to flow out of the upstream swirling space 301 is formed into an annular shape along the outer peripheral shape of the upstream swirling space 301, the refrigerant flowing out of the upstream swirling space 301 can flow in the axial direction from the outer peripheral side of the downstream swirling space 302 as indicated by solid arrows in FIG. 3.

With the above configuration, the refrigerant flowing out of the upstream swirling space 301 can be restrained from flowing toward the swirling center side of the downstream swirling space 302. Further, the refrigerant flowing out of the upstream swirling space 301 can merge into the flow from the outer peripheral side of the downstream swirling space 302 toward the nozzle passage 13a side, of the flow (flow indicated by dashed arrows in FIG. 3) of the liquid-phase refrigerant staying while circulating in the downstream swirling space 302.

Therefore, the flow of refrigerant staying while circulating in the downstream swirling space 302 is not blocked by the refrigerant flowing from the upstream swirling space 301 into the downstream swirling space 302, and the ratio of the gas-phase refrigerant to the refrigerant in the gas-liquid mixing state flowing into the nozzle passage 13a can be restrained from being lowered. As a result, the boiling of the liquid-phase refrigerant in the nozzle passage 13a is promoted, and the energy conversion efficiency in the nozzle passage 13a can be restrained from being lowered.

In the ejector 13 according to this embodiment, the upstream swirling space 301 is defined in a space between the upper plate 38a and the lower plate 38b, and the swirling promotion member 38 that swirls the refrigerant within the upstream swirling space 301 around the center axis by allowing the refrigerant on the center side of the upstream swirling space 301 to flow toward the outer peripheral side along the plate surface of the flow regulating plates 38c is provided.

Therefore, the shape of the outlet part 38e for allowing the refrigerant to flow out of the upstream swirling space 301 can be easily formed into an annular shape along the outer peripheral shape of the upstream swirling space 301. Further, since there is no need to provide the space for generating the swirling flow of the refrigerant outside the upstream swirling space 301, the body size can be restrained from being upsized as the overall ejector 13.

In addition, the ejector 13 of this embodiment employs the passage formation member 35 having a conical shape of which a cross-sectional area increases with distance from the depressurizing space 30b. The cross-sectional shape of the diffuser passage 13c is formed in an annular shape. Therefore, the diffuser passage 13c can have a shape to spread along the outer periphery of the passage formation member 35 in a direction away from the depressurizing space 30b.

Therefore, the dimension of the diffuser passage 13c in an axial direction (axial direction of the passage formation member 35) can be restrained from increasing. As a result, the upsizing of the body of the overall ejector 13 can be limited.

The gas-liquid separation space 30f that separates gas and liquid of the refrigerant that has flowed out of the diffuser passage 13c is formed in the body 30 of the ejector 13 according to this embodiment. Hence, the capacity of the gas-liquid separation space 30f can be effectively reduced as compared with a case in which a gas-liquid separation device is provided in addition to the ejector 13.

That is, in the gas-liquid separation space 30f according to this embodiment, since the refrigerant that flows out of the diffuser passage 13c annular in cross-section already has the velocity component in a swirling direction, there is no need to provide a space for generating the swirling flow of the refrigerant in the gas-liquid separation space 30f. Therefore, the capacity of the gas-liquid separation space 30f can be effectively reduced as compared with the case in which the gas-liquid separation device is provided apart from the ejector 13.

Second Embodiment

In the first embodiment, the example in which the swirling flow of the refrigerant is generated in the interior of the upstream swirling space 301 is described. In this embodiment, a description will be given of an example in which, as illustrated in FIGS. 6 to 8, with the application of a swirling promotion member 39, a swirling flow of the refrigerant is generated in the outer peripheral side of the upstream swirling space 301, and the refrigerant having a velocity component in the swirling direction flows into the upstream swirling space 301. FIGS. 6 to 8 correspond to FIGS. 2 to 4 in the first embodiment, respectively, and the same or equivalent parts to those in the first embodiment are denoted by identical symbols.

Specifically, a swirling promotion member 39 according to this embodiment includes a plate 39a formed into a disc shape, multiple flow regulating plates 39b projected downward from an outer peripheral part of the plate 39a, and a cylindrical protruding portion 39c projected from a center part of the plate 39a toward the same direction (downward) as that of the flow regulating plates 39b. The amount of projection from the plate 39a of the protruding portion 39c is equal to or larger than the amount of projection of the flow regulating plates 39b.

An outer diameter of the refrigerant inflow passage 31e according to this embodiment is formed to be larger than an outer diameter of a space defined in the interior of the nozzle body 32, and an outer diameter of the plate 39a is formed to be smaller than an outer diameter of the refrigerant inflow passage 31e. Therefore, a gap formed into an annular shape when viewed from the axial direction of the refrigerant inflow passage 31e is defined between an outer peripheral side of the plate 39a and an inner peripheral wall surface of the refrigerant inflow passage 31e. The annular gap configures an inlet part 39d for allowing the refrigerant flowing from the refrigerant inlet port 31a toward the nozzle body 32 side.

As illustrated in FIG. 8, the multiple flow regulating plates 39b are arranged in an annular shape around the center axis of the refrigerant inflow passage 31e. Further, the plate surfaces of the respective flow regulating plates 39b are so tilted or curved as to swirl a flow of the refrigerant around the center axis when viewed from the center axis direction. Those flow regulating plates 39b are disposed in an area extending from an outer periphery of the plate 39a to an outer periphery of a space defined in the interior of the nozzle body 32 when viewed from the center axis direction.

The center axis of the protruding portion 39c is disposed coaxially with the center axis of the refrigerant inflow passage 31e, and an outer diameter of the protruding portion 39c is formed to be smaller than an outer diameter of the space defined in the interior of the nozzle body 32. Therefore, a hollow cylindrical gap space formed in an annular shape in a cross-section perpendicular to the center axis direction is defined between the inner peripheral side of the multiple flow regulating plates 39b disposed annularly and the outer peripheral side of the protruding portion 39c.

Therefore, the refrigerant flowing into the refrigerant inflow passage 31e from the refrigerant inlet port 31a flows into the outer peripheral side of the multiple flow regulating plates 39b disposed annularly through the inlet part 39d on the outer peripheral side of the plate 39a. Further, the refrigerant flowing into the outer peripheral side of the multiple flow regulating plates 39b flows toward the inner peripheral side of the multiple flow regulating plates 39b. In this situation, the refrigerant flows along the plate surfaces of the multiple flow regulating plates 39b whereby the refrigerant swirls around the center axis.

The refrigerant flowing into the inner peripheral side of the multiple flow regulating plates 39b flows into the hollow cylindrical gap space defined between the inner peripheral side of the multiple flow regulating plates 39b and the outer peripheral side of the protruding portion 39c. The refrigerant flowing into the hollow cylindrical gap space flows into the space below (downstream side) of the swirling promotion member 39 from a lowermost side of the hollow cylindrical gap space while swirling around the center axis. Further, the refrigerant flowing into the space below the swirling promotion member 39 is introduced into the nozzle passage 13a side to be described later while swirling around the center axis.

As is apparent from the above description, in this embodiment, as illustrated in FIG. 7, the hollow cylindrical gap space defined between the inner peripheral side of the flow regulating plates 39b and the outer peripheral side of the protruding portion 39c is an example of the upstream swirling space 301 in which the refrigerant flowing from the external is swirled.

As illustrated in FIG. 8, the outlet part 39e disposed on a lowermost part (downstream side) of the hollow cylindrical gap space (upstream swirling space 301) for allowing the refrigerant to flow out of the upstream swirling space 301 is formed into an annular shape similar to the cross-sectional shape of the upstream swirling space 301 in a cross sectional surface perpendicular to the axial direction, that is, an annular shape along the outer peripheral shape of the upstream swirling space 301.

Further, the space below (downstream of) the swirling promotion member 39 is an example of a downstream swirling space 302 for introducing the refrigerant flowing out of the upstream swirling space 301 toward the depressurizing space 30b side while swirling. The other configuration and operation of the ejector 13 and the ejector refrigeration cycle 10 are similar to those of the first embodiment.

Therefore, even in the ejector 13 according to this embodiment, as in the first embodiment, the refrigerant (flow indicated by thick solid arrows in FIG. 7) flowing out of the upstream swirling space 301 can merge into the flow from the outer peripheral side of the downstream swirling space 302 toward the nozzle passage 13a side, of the flow (flow indicated by dashed arrows in FIG. 7) of the liquid-phase refrigerant staying and circulating in the downstream swirling space 302. As a result, as in the first embodiment, a reduction in the energy conversion efficiency in the nozzle passage 13a can be limited.

In the ejector 13 according to this embodiment, since the upstream swirling space 301 is formed into the rotating body shape that is annular in the cross-sectional surface perpendicular to the center axis direction, the shape of the outlet part 38e for allowing the refrigerant to flow out of the upstream swirling space 301 can be easily formed into an annular shape along the outer peripheral shape of the upstream swirling space 301.

Further, the swirling flow of the refrigerant is generated on the outer peripheral side of the upstream swirling space 301, and the refrigerant having the velocity component in a direction of swirling around the center axis flows into the upstream swirling space 301. Therefore, when a configuration in which the swirling flow of the refrigerant is generated in the interior of the upstream swirling space 301 is disposed, the degree of freedom of design of the configuration in which the swirling flow of the refrigerant is generated can be improved.

Third Embodiment

In the ejector refrigeration cycle 10a of this embodiment, as illustrated in an overall configuration diagram of FIG. 9, the ejector 13 according to the first embodiment is replaced with an ejector 53 and a gas-liquid separator 60.

The ejector 53 according to this embodiment does not have a function of the gas-liquid separator, but as in the ejector 13 of the first embodiment, performs a function of a refrigerant depressurizing device and also performs a function of a refrigerant circulation device (refrigerant transport device). A specific configuration of the ejector 53 will be described with reference to FIG. 10.

The ejector 53 has a nozzle 531 and a body 532 as illustrated in FIG. 10. First, the nozzle 531 is made of metal (for example, stainless alloy) shaped into substantially a hollow cylinder gradually tapered toward a flowing direction of the refrigerant, and the refrigerant flowing into the nozzle 531 is isentropically depressurized, and ejected from a refrigerant ejection port 531a defined on the most downstream side in the refrigerant flow.

The interior of the nozzle 531 is formed with a swirling space 531c in which the refrigerant flowing from a refrigerant inlet port 531b swirls, and a refrigerant passage in which the refrigerant flowing out of the swirling space 531c is depressurized.

In detail, the swirling space 531c is formed in the interior of a cylindrical part 531g disposed on the upstream side of the nozzle 531 in the refrigerant flow. Therefore, the cylindrical part 531g may be used as an example of a swirling space formation member having the swirling space 531c, and in this embodiment, the swirling space formation member and the nozzle are integrated with each other.

Further, a cylindrical member 531h formed into a cylindrical shape smaller than an inner diameter of the cylindrical part 531g is disposed on the upstream side in the refrigerant flow in the interior of the cylindrical part 531g. The axial length of the cylindrical member 531h is formed to be shorter than an axial length of the cylindrical part 531g, and disposed coaxially with a center axis of the cylindrical part 531g.

Therefore, in an area where the cylindrical part 531g overlaps with the cylindrical member 531h when viewed from the radial direction, a hollow cylindrical space formed into an annular shape in a cross-section perpendicular to the center axis direction is defined between the inner peripheral side of the cylindrical part 531g and the outer peripheral side of the cylindrical member 531h. In an area where the cylindrical part 531g does not overlap with the cylindrical member 531h, a cylindrical space formed into a circular shape in a cross-section perpendicular to the center axis direction is defined on the inner peripheral side of the cylindrical part 531g.

Further, a refrigerant inflow passage that connects the refrigerant inlet port 531b and the swirling space 531c is opened in the hollow cylindrical space, and extends in a tangential direction of an inner wall surface of the swirling space 531c when viewed from a center axis direction of the swirling space 531c.

With the above configuration, the refrigerant flowing into the hollow cylindrical space from the refrigerant inlet port 531b flows along an inner peripheral wall surface of the cylindrical part 531g, and swirls about a center axis of the cylindrical part 531g. Further, the refrigerant flowing out of the hollow cylindrical space flows into the cylindrical space while swirling around the center axis.

As is apparent from the above description, in this embodiment, the hollow cylindrical space within the cylindrical part 531g is an example of an upstream swirling space 311 in which the refrigerant flowing out of the external is swirled, and the cylindrical space within the cylindrical part 531g is an example of a downstream swirling space 312 that introduces the refrigerant flowing out of the upstream swirling space 311 into a minimum passage area part 531d of the nozzle 531 while swirling.

An outlet part 311a disposed on the most downstream side of the hollow cylindrical space (upstream swirling space 311) for allowing the refrigerant to flow out of the upstream swirling space 311 is formed into an annular shape similar to the cross-sectional shape of the upstream swirling space 311 in a cross sectional surface perpendicular to the axial direction, that is, an annular shape along the outer peripheral shape of the upstream swirling space 311.

In this example, since the downstream swirling space 312 is formed into the hollow rotating body shape, a refrigerant pressure on the center axis side is reduced more than the refrigerant pressure on the outer peripheral side due to the action of a centrifugal force generated by swirling the refrigerant in the downstream swirling space 312. Accordingly, in this embodiment, in a normal operation of the ejector refrigeration cycle 10, the refrigerant pressure on the center axis side in the downstream swirling space 312 is reduced to a pressure at which the refrigerant is depressurized and boiled (cavitation is generated).

The adjustment of the refrigerant pressure on the center axis side in the downstream swirling space 312 can be realized by adjusting the swirling flow rate of the refrigerant swirling in the downstream swirling space 312. Further, the swirling flow rate can be adjusted by, for example, adjusting an area ratio of the passage sectional area of the refrigerant inflow passage to the sectional area of the downstream swirling space 312 perpendicular to the axial direction. Meanwhile, the swirling flow rate in this embodiment means the flow rate of the refrigerant in the swirling direction in the vicinity of the outermost peripheral part of the swirling space 531c.

Further, the refrigerant passage defined in the interior of the nozzle 531 is formed with the minimum passage area part 531d having a refrigerant passage area most reduced, a tapered part 531e having a refrigerant passage area gradually reduced toward the minimum passage area part 531d from the swirling space 531c, and a divergent part 531f having a refrigerant passage area gradually enlarged from the minimum passage area part 531d toward the refrigerant ejection port 531a.

The body 532 is made of metal (for example, aluminum) or resin formed into substantially a hollow cylindrical shape, functions as a fixing member for internally supporting and fixing the nozzle 531, and forms an outer shell of the ejector 53. More specifically, the nozzle 531 is fixed by press fitting so as to be housed in the interior of the body 532 on one end side in the longitudinal direction of the body 532.

A refrigerant suction port 532a is defined in a portion corresponding to an outer peripheral side of the nozzle 531 on an outer peripheral side surface of the body 532. The refrigerant suction port 532a is a through-hole that penetrates through a portion corresponding to an outer peripheral side of the nozzle 531 on the outer peripheral side surface of the body 532, and disposed to communicate with the refrigerant ejection port 531a of the nozzle 531. The refrigerant suction port 532a draws the refrigerant flowing out of an evaporator 14 into the interior of the ejector 53 due to the suction action of the ejection refrigerant ejected from the refrigerant ejection port 531a of the nozzle 531. The refrigerant suction port 532a may be used as an example of the fluid suction port for drawing the fluid due to the suction action of the ejected fluid at a high speed which is ejected from the nozzle 531.

Further, the body 532 internally includes a diffuser portion 532b that mixes the ejection refrigerant ejected from the refrigerant ejection port 531a with the suction refrigerant drawn from the refrigerant suction port 532a to increase the pressure, and a suction passage 532c that introduces the suction refrigerant drawn from the refrigerant suction port 532a into the diffuser portion 532b. The diffuser portion 532b may be used as an example of a pressure increase part for mixing and pressurizing the ejection fluid ejected from the nozzle 531 with the suction fluid drawn from the fluid suction port.

The suction passage 532c is formed by a space between an outer peripheral side around a tip of a tapered shape of the nozzle 531 and an inner peripheral side of the body 532. A refrigerant passage area of the suction passage 532c is gradually reduced toward the refrigerant flow direction. With the above configuration, a flow rate of the suction refrigerant flowing in the suction passage 532c is gradually accelerated, and an energy loss (mixing loss) in mixing the suction refrigerant with the ejection refrigerant is reduced by the diffuser portion 532b.

The diffuser portion 532b is disposed to be continuous to an outlet side of the suction passage 532c, and formed so that a refrigerant passage area gradually increases. This configuration performs a function of converting a velocity energy of a mixed refrigerant of the ejection refrigerant and the suction refrigerant into a pressure energy, that is, functions as a pressure increase part that decelerates a flow rate of the mixed refrigerant, and pressurizes the mixed refrigerant.

More specifically, a wall surface shape of the inner peripheral wall surface of the body 532 forming the diffuser portion 532b according to this embodiment is defined by the combination of multiple curves as illustrated in a cross-section along the axial direction in FIG. 2. A spread degree of the refrigerant passage cross-sectional area of the diffuser portion 532b gradually increases toward the refrigerant flow direction, and thereafter again decreases, as a result of which the refrigerant can be isentropically pressurized.

As illustrated in FIG. 9, a refrigerant outlet side of the diffuser portion 532b of the ejector 53 is connected with a refrigerant inlet port of the gas-liquid separator 60. The gas-liquid separator 60 is a gas-liquid separation device that separates gas and liquid of the refrigerant flowing into the interior of the gas-liquid separator 60 from each other.

A liquid-phase refrigerant outlet port of the gas-liquid separator 60 is connected with the refrigerant inlet side of the evaporator 14. The gas-phase refrigerant outlet port of the gas-liquid separator 60 is connected with an inlet side of the compressor 11. Other structures and operations are the same as those of the first embodiment.

Therefore, in the ejector 53 according to this embodiment, as in the first embodiment, the refrigerant flowing out of the upstream swirling space 311 (a flow indicated by dashed arrows in FIG. 10) can merge into the flow from the outer peripheral side of the downstream swirling space 312 toward the minimum passage area part 531d side of the nozzle 531, of the flow (flow indicated by dashed arrows in FIG. 10) of the liquid-phase refrigerant staying and circulating in the downstream swirling space 312. As a result, as in the first embodiment, a reduction in the nozzle efficiency of the nozzle 531 can be limited.

The present disclosure is not limited to the above-described embodiments, but various modifications can be made thereto as follows without departing from the spirit of the present disclosure.

(1) In the first and second embodiments, the examples in which the upstream swirling space 301 and the downstream swirling space 302 are defined by the swirling promotion members 38 and 39, respectively, are described. However, the upstream swirling space 301 and the downstream swirling space 302 are not limited to the above configurations.

For example, in the ejector 13 according to the first and second embodiments, the refrigerant inflow passage 31e is defined to extend in the tangential direction of the inner wall surface of the swirling space 30a, and the same cylindrical member as that in the third embodiment is disposed in the interior of the swirling space 30a. The hollow cylindrical space defined in the area where the swirling space 30a overlaps with the cylindrical member may be defined as the upstream swirling space 301, and the cylindrical space defined in the area where the swirling space 30a does not overlap with the cylindrical member may be defined as the downstream swirling space 302.

In the ejector 53 according to the third embodiment, the swirling promotion members 38 and 39 according to the first and second embodiments are disposed in the interior of the cylindrical part 531g. As a result, as in the first and second embodiments, the upstream swirling space 311 and the downstream swirling space 312 may be defined.

(2) In the above first and second embodiments, the description has been given of the example in which the driving device 37 that displaces the passage formation member 35 includes the sealed space 37b in which the temperature sensitive medium having the pressure changed according to a change in the temperature is sealed, and the diaphragm 37a that is displaced according to the pressure of the temperature sensitive medium within the sealed space 37b. However, the driving device is not limited to this configuration.

For example, a thermo wax that changes a volume with temperature as a temperature sensitive medium may be applied, or the driving device formed of a shape memory alloy elastic member as a driving device may be applied. Furthermore, the driving device in which the passage formation member 35 is displaced by an electric motor may be applied as the driving device as in the second embodiment.

(3) In the above-mentioned third embodiment, a detail of the arrangement of the ejector 53 is not described. In the arrangement of the ejector 53, the axial direction of the nozzle 531 may be disposed in parallel to a vertical direction as in the first and second embodiments, or may be disposed in parallel to another direction (for example, a horizontal direction). This is because the refrigerant swirling within the swirling space 531c is unlikely to be affected by a gravity force because the swirling speed is relatively high.

(4) In the above embodiments, the details of the liquid-phase refrigerant outlet port 31c of the ejector 13 and the gas-phase refrigerant outlet port of the gas-liquid separator 60 are not described. A depressurizing device (for example, side fixed aperture formed of an orifice or a capillary tube) for depressurizing the refrigerant may be arranged on those refrigerant outlet ports.

(5) In the above embodiments, the example in which the ejector refrigeration cycle 10 including the ejector 13 of the present disclosure is applied to a vehicle air conditioning apparatus has been described, but the application of the ejector refrigeration cycle 10 having the ejector 13 of the present disclosure is not limited to this configuration. For example, the ejector refrigeration cycle 10 may be applied to, for example, a stationary air conditioning apparatus, cold storage warehouse, a cooling heating device for a vending machine, etc.

(6) Examples in which a subcooling heat exchanger is employed as the heat radiator 12 have been described in the above-mentioned embodiments, but, needless to say, a normal heat radiator formed of only the condenser 12a may be employed as the heat radiator 12. In the above-described embodiments, the example in which components such as the body 30 of the ejector 13, and components such as the nozzle 531 of the ejector 53 and the body 532 are formed of metal is described. However, as long as functions of the components can be exerted, the materials are not limited. Accordingly, those components may be made of a resin.

The present disclosure has been made based on the following analytical findings. First, the present inventors have confirmed a flow of the refrigerant within the swirling space when the refrigerant pressure on the swirling center side is reduced down to a pressure at which the refrigerant is depressurized and boiled by swirling the refrigerant for refrigeration cycle in the swirling space of the depressurizing device by simulation analysis.

FIG. 11 is a cross-sectional view along an axial direction of a swirling space 70d showing a result of the simulation analysis, in which an area in which the liquid-phase refrigerant is present is indicated by dot hatching, and flow lines of the refrigerant in that area is indicated by respective arrows.

The flow lines indicated by the respective arrows are flow lines illustratable in a cross-section in the axial direction in FIG. 11, that is, flow lines that can be drawn by velocity components from which a velocity component in the swirling direction is removed. The swirling space 70d is defined within a main body 70a of a depressurizing device 70, and formed into a hollow rotating body shape (in more detail, a shape in which a cylindrical space is coupled coaxially with a conical space).

It is confirmed from FIG. 11 that a gas-phase refrigerant is unevenly distributed in a columnar shape on a swirling center side of the swirling space 70d. A liquid-phase refrigerant around the gas-phase refrigerant (hereinafter referred to as “gas column”) unevenly distributed in the columnar shape flows from a minimum passage area part 70b side that is one end side along the gas column in the axial direction (lower side in FIG. 11) toward the other end side in the axial direction (upper side in FIG. 11) as indicated by the flow lines of dashed arrows.

Further, the refrigerant that flows along the gas column and reaches the other end side in the axial direction flows on an outer peripheral side of the swirling space 70d, and flows toward the minimum passage area part 70b side from the outer peripheral side. The refrigerant that reaches the minimum passage area part 70b side again flows from the minimum passage area part 70b side toward the other end side in the axial direction along the gas column. In other words, it can be confirmed that the liquid-phase refrigerant around the gas column stays while circulating around the gas column as indicated by dashed arrows in FIG. 11.

As described above, the liquid-phase refrigerant around the gas column stays while circulating, and the liquid-phase refrigerant flows along the gas column from the minimum passage area part 70b side toward the other end side in the axial direction. Therefore, it is understood that an angular momentum of the swirling flow of the refrigerant in the vicinity of the minimum passage area part 70b is transmitted to the refrigerant in an overall area on the swirling center side in the axial direction. Further, it is understood that the depressurization and boiling of the refrigerant in the overall area on the swirling center side in the axial direction are promoted by the transmission of the angular momentum, and the gas column is formed over the overall area within the swirling space 70d in the axial direction.

On the other hand, the refrigerant flowing from a refrigerant inlet port 70c connected to a side surface of the main body 70a into the swirling space 70d flows toward the minimum passage area part 70b side along the outer peripheral side of the refrigerant staying while circulating around the gas column as shown by flow lines indicated by thick solid arrows in FIG. 11.

In this situation, since the refrigerant flowing into the swirling space 70d is a high pressure refrigerant flowing out of the radiator, even if the refrigerant flows in the tangential direction of the swirling space 70d circular in the cross-section, the refrigerant flowing into the swirling space 70d is liable to flow toward the low pressure side (that is, swirling center side) under an operation condition where a pressure of the high pressure refrigerant is relatively high as in a high load operation of the refrigeration cycle device.

When the refrigerant flowing into the swirling space 70d flows toward the swirling center side, a flow of the liquid-phase refrigerant circulating around the gas column is blocked as indicated by a thick solid arrow on a right side in FIG. 11. For that reason, the angular momentum of the swirling flow of the refrigerant in the vicinity of the minimum passage area part 70b described above is unlikely to be transmitted to the refrigerant in the overall area on the swirling center side in the axial direction, and the depressurization and boiling of the refrigerant on the swirling center side may be limited.

As a result, a ratio of the gas-phase refrigerant to the refrigerant in the gas-liquid mixing state which flows in the minimum passage area part is lowered, and the nozzle efficiency may be lowered. The refrigerant in the gas-liquid mixing state does not mean only the refrigerant in a gas-liquid two-phase state, but includes the refrigerant in a state where air bubbles are mixed in the refrigerant in a subcooled liquid-phase state.

On the contrary, in order to allow the refrigerant flowing from the refrigerant inlet port 70c into the swirling space 70d to flow toward the minimum passage area part 70b so as not to block the flow of the liquid-phase refrigerant circulating around the gas column, as is apparent from FIG. 11, it is desirable that the refrigerant may merge into a flow from the outer peripheral side toward the minimum passage area part 70b side, of the refrigerant flow of the liquid-phase refrigerant staying and circulating around the gas column.

Claims

1. An ejector comprising:

a swirling space formation member having a swirling space in which a fluid is swirled;

a nozzle that depressurizes and ejects the fluid flowing out of the swirling space; and

a body including a fluid suction port that draws a fluid due to a suction action of the ejected fluid at high speed which is ejected from the nozzle, and a pressure increase part that mixes the ejected fluid with the suction fluid drawn from the fluid suction port and increases a pressure of the mixed fluid, wherein

the swirling space includes an upstream swirling space in which the fluid flowing from an external is swirled, and a downstream swirling space that introduces the fluid flowing out of the upstream swirling space into the nozzle with keeping the fluid swirling,

the upstream swirling space and the downstream swirling space have respective rotating body shapes in which center axes are disposed coaxially with each other,

the upstream swirling space has an outlet part through which the fluid outflow to the downstream swirling space, and the outlet part has an annular shape along an outer peripheral shape of the upstream swirling space in a cross sectional surface perpendicular to the center axis, and

the downstream swirling space has a circular shape in a cross sectional surface perpendicular to the center axis.

2. An ejector for a vapor compression refrigeration cycle device, comprising:

a body including a refrigerant inlet port, a swirling space in which a refrigerant flowing from the refrigerant inlet port is swirled, a depressurizing space in which the refrigerant flowing out of the swirling space is depressurized, a suction passage that communicates with a downstream side of the depressurizing space in a refrigerant flow and draws a refrigerant from an external, and a pressurizing space in which an ejection refrigerant ejected from the depressurizing space is mixed with a suction refrigerant drawn from the suction passage; and

a passage formation member that includes at least a portion disposed inside the depressurizing space, and a portion disposed inside the pressurizing space, the passage formation member having a conical shape which increases in cross-sectional area in a direction away from the depressurizing space, wherein

a refrigerant passage provided between an inner peripheral surface of the body defining the depressurizing space and an outer peripheral surface of the passage formation member is a nozzle passage functioning as a nozzle that depressurizes and ejects the refrigerant flowing out of the swirling space,

a refrigerant passage provided between an inner peripheral surface of the body defining the pressurizing space and an outer peripheral surface of the passage formation member is a diffuser passage functioning as a diffuser that mixes and pressurizes the ejection refrigerant and the suction refrigerant,

the swirling space includes an upstream swirling space in which the refrigerant flowing from an external is swirled, and a downstream swirling space in which the refrigerant flowing out of the upstream swirling space is introduced into the nozzle passage with swirling,

the upstream swirling space and the downstream swirling space have respective rotating body shapes in which center axes are disposed coaxially with each other,

the upstream swirling space has an outlet part through which the refrigerant outflow to the downstream swirling space, and the outlet part has an annular shape along an outer peripheral shape of the upstream swirling space in a cross sectional surface perpendicular to the center axis, and

the downstream swirling space has a circular shape in a cross sectional surface perpendicular to the center axis.

3. The ejector according to claim 1, further comprising a swirling promotion member that swirls the refrigerant in the upstream swirling space around the center axis, wherein

the swirling promotion member includes a flow regulating plate, and the refrigerant adjacent to a center axis of the upstream swirling space flows radially outward along the flow regulating plate.

4. The ejector according to claim 1, wherein

the upstream swirling space has an annular shape in a cross sectional surface perpendicular to the center axis, and

the upstream swirling space is configured to allow the refrigerant having a velocity component in a direction of swirling around the center axis of the upstream swirling space to flow into the upstream swirling space.

5. The ejector according to claim 2, further comprising a swirling promotion member that swirls the refrigerant in the upstream swirling space around the center axis, wherein

the swirling promotion member includes a flow regulating plate, and the refrigerant adjacent to a center axis of the upstream swirling space flows radially outward along the flow regulating plate.

6. The ejector according to claim 2, wherein

the upstream swirling space has an annular shape in a cross sectional surface perpendicular to the center axis, and

the upstream swirling space is configured to allow the refrigerant having a velocity component in a direction of swirling around the center axis of the upstream swirling space to flow into the upstream swirling space.