Ejector

Abstract

Ejector for use in a refrigeration circuit device, which features: a drive-side nozzle (31) designed to expand a drive-side coolant and accelerate it to a supersonic speed and inject the drive-side coolant as a drive-side injection coolant in a gas-liquid two-phase state; and a body (32) which includes: a coolant suction port (321) designed to draw suction-side coolant; a suction-side nozzle (322) designed to expand and inject the suction-side coolant, which is drawn in as suction-side injection coolant through the coolant suction port (321); a mixing section (323) designed to mix the suction-side injection coolant injected from the suction-side nozzle (322) and the drive-side injection coolant injected from the drive-side nozzle (31); and a diffuser section (324) designed to convert kinetic energy of the mixed coolant formed from the suction-side injection coolant and the drive-side injection coolant mixed in the mixing section (323) into pressure energy, wherein: the drive-side nozzle (31) has a converging section (31b), a neck section (31c) and a diverging section (31d), wherein the diverging section (31d) has a passage cross-sectional area for the passage of the coolant, which is progressively enlarged from the neck section (31c) to a drive-side injection port (31e); the drive-side nozzle (31) is arranged coaxially in a cylindrical space formed on an inside of the body (32); a coolant passage of the suction-side nozzle (322) is formed between an outer circumferential surface of the diverging section (31d) and an inner circumferential surface of the body (32) and has a cross-section that is formed in an annular shape; the drive-side injection port (31e) of the drive-side nozzle (31) and a suction-side injection port (322a) of the suction-side nozzle (322) are open such that an injection direction of the drive-side injection coolant injected by the drive-side injection port (31e) and an injection direction of the suction-side injection coolant injected by the suction-side injection port (322a) coincide; a pressure of the drive-side injection coolant is higher than a pressure of the suction-side injection coolant; and when the mixed coolant flows out of the mixing section (323) and into the diffuser section (324), a pressure of the mixed coolant measured on a central axis of the mixing section (323) and a pressure of the mixed coolant measured on a wall surface of the mixing section (323) are equal, while a flow velocity of the mixed coolant is a subsonic velocity.

Description

Technical field

[0001] The present invention relates to an ejector designed to inject a fluid in a gas-liquid two-phase state from a drive-side nozzle. State of the art

[0002] So far, an ejector refrigeration cycle is known, which is a refrigeration cycle device that has an ejector.

[0003] In an ejector refrigeration cycle, the pressure of a refrigerant being drawn into a compressor can be increased above the refrigerant evaporation pressure at an evaporator by means of a pressure amplification process in the ejector. This reduces the energy consumption of the compressor in the ejector refrigeration cycle, thus improving the cycle's coefficient of performance (COP). Therefore, improving the pressure amplification capacity of the ejector is an effective way to improve the COP of the ejector refrigeration cycle.

[0004] In this regard, patent literature 1 discloses an ejector used in an ejector refrigeration cycle. In this ejector, a mixing section, in which injected and drawn-in coolant are mixed, has a frustoconical shape that progressively increases the cross-sectional area of ​​the passage towards a downstream side in the coolant flow direction. As a result, in the ejector described in patent literature 1, energy loss of the coolant in the mixing section is limited, and the pressure increase of the coolant at a diffuser section is increased.

[0005] Furthermore, patent literature 2 discloses an industrial ejector (hereinafter referred to as a vapor ejector) used in a vacuum ejection device. In this vapor ejector, the pressure of a gas-phase fluid (in particular air) is amplified by means of a pressure recovery process of a shock wave. Patent literature 2 further states that in the vapor ejector, the pressure recovery process of the shock wave can be improved by reducing the Mach number of the air at the upstream part of the shock wave.

[0006] Patent literature 3 discloses an ejector with a mixing and pressure boosting section. Patent literature 4 to 6 disclose further prior art. References ListPatent literature Patent literature 1: US 9,568,220 B2 Patent literature 2: JP S59-151 000 A Patent literature 3: DE 10 2009 012 158 A1 Patent Literature 4: CN 201 461 559 U Patent Literature 5: CN 105 855 084 A Patent literature 6: DE 11 2014 002 882 B4 Summary of the invention

[0007] In the ejector described in patent literature 1, the cross-sectional area of ​​the coolant passage is constant. Therefore, simply by manufacturing the flow path of the mixing section in a frustoconical shape, it is difficult to achieve excellent pressure amplification capacity under all operating conditions, regardless of any changes in the load of the refrigeration circuit device.

[0008] Furthermore, in the ejector used in the ejector refrigeration circuit, there is no guarantee that the pressure increase of the coolant will be improved by improving the pressure recovery process of the shock wave.

[0009] This is due to the following differences. These are that in the vapor ejector, the gas-phase fluid is injected from the drive-side nozzle, while in the ejector used in the refrigeration circuit, the gas-liquid two-phase refrigerant is injected from the drive-side nozzle. Furthermore, the shock wave generation mode differs between the vapor ejector that injects the gas-phase fluid from the drive-side nozzle and the ejector that injects the gas-liquid two-phase fluid from the drive-side nozzle.

[0010] It is an object of the present invention to provide an ejector which has an excellent pressure amplification capacity by means of the use of a shock wave, regardless of the occurrence of a change in the load in the refrigeration circuit device.

[0011] The above problem is solved by an ejector with the features according to claim 1. The ejector according to the invention is used in a refrigeration circuit device and includes a drive-side nozzle and a body.

[0012] The drive-side nozzle is designed to expand the drive-side coolant and accelerate it to supersonic speed, injecting the drive-side coolant as a drive-side injection coolant in a gas-liquid two-phase state.

[0013] The body includes a coolant suction port, a suction nozzle, a mixing section, and a diffuser section. The coolant suction port is designed to draw in a suction-side coolant. The suction nozzle is designed to expand and inject the suction-side coolant drawn in through the suction port as suction-side injection coolant. The mixing section is designed to mix the suction-side injection coolant injected by the suction nozzle with the drive-side injection coolant injected by the drive-side nozzle. The diffuser section is designed to convert the kinetic energy of the mixed coolant, formed from the suction-side injection coolant and the drive-side injection coolant within the mixing section, into pressure energy.

[0014] The drive-side injection port of the drive-side nozzle and a suction-side injection port of the suction-side nozzle are opened such that an injection direction of the drive-side injection coolant injected from the drive-side injection port and an injection direction of the suction-side injection coolant injected from the suction-side injection port coincide.

[0015] The pressure of the drive-side injection coolant is higher than the pressure of the suction-side injection coolant. As the mixed coolant flows from the mixing section into the diffuser section, the pressure of the mixed coolant measured along a central axis of the mixing section and the pressure of the mixed coolant measured along a wall surface of the mixing section are the same, while the flow velocity of the mixed coolant is subsonic.

[0016] This means that the pressure of the drive-side injection coolant, which is reduced at the drive-side nozzle, is higher than the pressure of the suction-side injection coolant, which is reduced at the suction-side nozzle. Therefore, the drive-side coolant is underexpanded, regardless of any changes in the load of the refrigeration circuit device via the drive-side nozzle, in order to reliably generate the shock wave in the mixing section. Consequently, the pressure of the mixed coolant can be increased by means of the pressure recovery process of the shock wave in the mixing section.

[0017] Furthermore, the flow velocity of the mixed coolant exiting the mixing section and entering the diffuser section is subsonic. Therefore, even if a pseudo-shock wave, which could generate energy loss, is created in the mixing section by means of an initial shock wave generated by the drive-side injection coolant, the pseudo-shock wave can be quickly extinguished.

[0018] Furthermore, in the mixing section, the drive-side injection coolant and the suction-side injection coolant are mixed together in such a way that the pressure of the mixed coolant measured at the central axis and the pressure of the mixed coolant measured at the wall surface of the mixing section are identical when the mixed coolant flows out of the mixing section and into the diffuser section. Even if the generating area of ​​the pseudo-shock wave changes due to a change in the load in the refrigeration circuit device, the pseudo-shock wave can be reliably canceled out in the mixing section.

[0019] As a result, it is possible to provide an ejector that exhibits excellent pressure amplification capacity by utilizing the shock wave, regardless of the occurrence of the change in load in the refrigeration circuit device that has the ejector.

[0020] Here, the pseudo-shock wave is a phenomenon in which an expansion wave is generated on a downstream side of the initial shock wave, which is generated by means of the drive-side injection coolant, so that the coolant pressure measured at the central axis and the coolant pressure measured at the wall surface in the coolant passage each have different values, and thereby a shock wave is generated again, as described later in the embodiments. Brief description of the drawings Fig. Figure 1 is a schematic view showing the overall structure of an ejector refrigeration cycle of a first embodiment. Fig. Figure 2 is an axial cross-sectional view of an ejector of the first embodiment. Fig. Figure 3 is an explanatory diagram to illustrate a pseudo-shock wave. Fig. Figure 4 is a graph that shows a relationship between an initial Mach number and a mixing section distance required to cancel out a pseudoshock wave. Fig. Figure 5 is a graph showing a pressure change on an inner wall surface of the ejector relative to a change in coolant pressure at an outlet of a diffuser section. Fig. Figure 6 is an explanatory diagram that schematically shows a generation mode of a pseudo-shock wave at the ejector under operating conditions OP1. Fig. Figure 7 is an explanatory diagram that schematically shows a generation mode of a pseudo-shock wave at an ejector under an operating condition OP2. Fig. Figure 8 is an explanatory diagram that schematically shows a generation mode of a pseudo-shock wave at the ejector under operating conditions OP3. Fig. Figure 9 is an explanatory diagram that schematically shows a generation mode of a pseudo-shock wave at the ejector under an operating condition OP4. Fig. Figure 10 is an explanatory diagram that schematically shows a generation mode of an expansion shaft at a drive-side nozzle of the ejector of the first embodiment. Fig. Figure 11 is an axial cross-sectional view of an ejector of a second embodiment. Fig. Figure 12 is a schematic view showing the overall structure of an ejector refrigeration cycle of a third embodiment. Description of the embodiments

[0021] The embodiments for implementing the present invention are described below with reference to the drawings. In each of the following embodiments, the same reference numerals may be assigned to sections that are the same as or similar to those described in a preceding embodiment, and the description thereof may be omitted. Furthermore, if only a part of any component is described in the embodiment, the description of the remaining components as described in the preceding embodiment may be applied to the remaining components. In addition to the combinations of sections, which are shown to be combinable in the respective embodiments, it is also possible to partially combine the embodiments, even if this is not explicitly shown, provided that the combinations are not impossible. (First embodiment)

[0022] A first embodiment of the present disclosure is described with reference to Fig. 1 to 10 described. As in Fig. Figure 1 shows an ejector 13 of the present embodiment being used in an ejector refrigeration circuit 10. The ejector refrigeration circuit 10 is a vapor compression refrigeration circuit device that includes the ejector. The ejector refrigeration circuit 10 is used in an air handling unit for a vehicle and is designed to cool air that is to be blown into a passenger compartment (hereinafter also referred to as the vehicle cabin) of the vehicle, which serves as an air handling unit.

[0023] The ejector refrigeration circuit 10 uses an HFO refrigerant (specifically R1234yf) as the refrigerant. The ejector refrigeration circuit 10 is a subcritical refrigeration circuit in which the refrigerant pressure on a high-pressure side does not exceed a critical refrigerant pressure. Refrigeration oil for lubricating a compressor 11 of the ejector refrigeration circuit 10 is mixed with the refrigerant. A portion of the refrigeration oil is circulated in the ejector refrigeration circuit 10 together with the refrigerant.

[0024] The compressor 11 is designed to draw in, compress, and discharge the refrigerant in the ejector refrigeration circuit 10. The compressor 11 is an electric compressor in which a fixed-capacity compression mechanism has a constant discharge volume and is rotated by an electric motor. The rotational speed (for example, a refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output by a control device 20, which will be described later.

[0025] A coolant inlet of the radiator 12 is connected to a discharge outlet of the compressor 11. The radiator 12 is a heat-emitting heat exchanger that transfers heat between the high-pressure coolant discharged by the compressor 11 and the ambient air (e.g., outside air) blown by a cooling fan 12a, in order to release heat from the high-pressure coolant and thereby condense it. The cooling fan 12a is an electric fan whose rotational speed (e.g., a blowing capacity) is controlled by a control voltage output by the control device 20.

[0026] A drive-side inlet 31a of the drive-side nozzle 31 of the ejector 13 is connected to a coolant outlet of the radiator 12. The ejector 13 is a coolant decompression device designed to decompress drive-side coolant dispensed by the radiator 12. The ejector 13 is also a coolant transport device designed to draw in and transport the coolant dispensed by an evaporator 16, which will be described later. Furthermore, the ejector 13 is also a coolant pressure intensification device designed to increase, for example, the pressure of the coolant applied to it.

[0027] The construction of ejector 13 is described in detail with reference to Fig. 2 described. The ejector 13 includes the drive-side nozzle 31 and a body 32.

[0028] The drive-side nozzle 31 expands the drive-side coolant isentropically and injects the drive-side coolant, accelerated to supersonic speed and in a gas-liquid biphase state, into a mixing section 323 of the body 32. The drive-side inlet 31a, which receives the drive-side coolant (the high-pressure coolant) discharged by the radiator 12, is located at the most upstream section of the drive-side nozzle in the coolant flow direction. A drive-side injection port 31e, which injects the drive-side injection coolant, is located at the most downstream section of the drive-side nozzle 31 in the coolant flow direction.

[0029] The drive-side nozzle has a converging section 31b, a throat section 31c, and a diverging section 31d. The converging section 31b has a flow cross-sectional area for the coolant that has entered through the drive-side inlet 31a, and this flow cross-sectional area is progressively reduced towards the downstream side in the direction of coolant flow. The throat section 31c has a flow cross-sectional area for the coolant, and this flow cross-sectional area is minimized (for example, is smallest) in the drive-side nozzle 31. The diverging section 31d has a flow cross-sectional area for the coolant, and this flow cross-sectional area is progressively increased from the throat section 31c to the drive-side injection port 31e. That is, a so-called Laval nozzle is used as the drive-side nozzle 31 in the ejector 13.

[0030] The drive-side nozzle 31 is formed by plastically deforming a cylindrical, tubular component made of metal (in this embodiment, stainless steel). In the drive-side nozzle 31, the thickness of the converging section 31b and the thickness of the diverging section 31d are essentially constant. Therefore, the external shape of the converging section 31b and the external shape of the diverging section 31d change in the same way as the shape of the coolant passage formed therein. Of course, the drive-side nozzle 31 can also be formed by cutting a block-shaped metal component.

[0031] The shape of the coolant passage of the drive-side nozzle 31 is designed such that the flow velocity of the drive-side injection coolant injected from the drive-side injection port 31e is equal to or greater than the two-phase speed of sound, which is the speed of sound of the gas-liquid two-phase coolant. Furthermore, the shape of the coolant passage of the drive-side nozzle 31 is also designed to ensure that the flow velocity of the gas-phase coolant in the passage of the drive-side nozzle 31 is equal to or less than the gas-phase speed of sound (also referred to as the gas-sonic speed), which is the speed of sound of the gas-phase coolant.

[0032] In particular, the shape of the coolant passage of the drive-side nozzle 31 is determined such that a relationship between a neck section cross-sectional area Anzth and a drive-side injection port cross-sectional area Anzout satisfies the following equation F1. 1.3≤Anzout / Anzth≤1.5

[0033] Here, the neck section cross-sectional area Anzth is a through cross-sectional area of ​​neck section 31c. The drive-side injection port cross-sectional area Anzout is a through cross-sectional area of ​​the drive-side injection port 31e.

[0034] Furthermore, the body 32 is formed by means of a tubular component made of metal (aluminum in this embodiment). The body 32 forms an outer shell of the ejector 13. The drive-side nozzle 31 is attached by press-fitting (interference fit) into the interior of an end section of the body 32. A central axis of the drive-side nozzle 31 and a central axis of the body 32 are coaxial with each other. The body 32 can also be formed by means of a tubular component made of resin.

[0035] The body 32 has a coolant suction port 321, a suction-side nozzle 322, the mixing section 323 and a diffuser section 324.

[0036] The coolant suction port 321 is formed on a circumferential surface of the body 32. The coolant suction port 321 is a through-hole that draws the suction-side coolant, which is discharged from the evaporator 16, into the interior of the ejector 13 by means of the suction action of the drive-side injection coolant, which is injected from the drive-side nozzle 31.

[0037] The coolant suction port 321 is connected to a suction chamber 321a formed on the inside of the body 32. The suction chamber 321a is formed by coaxially aligning the converging section 31b and the diverging section 31d of the drive-side nozzle 31 within a cylindrical space on the inside of the body 32. Therefore, the suction chamber 321a is formed on the radially outer side of the converging section 31b and the diverging section 31d of the drive-side nozzle 31 and has an annular cross-section.

[0038] The suction-side nozzle 322 expands the suction-side coolant, which is drawn into the suction chamber 321a through the coolant suction port 321, and injects the suction-side coolant as suction-side injection coolant into the mixing section 323. In the body 32, the suction-side nozzle 322 is formed on the radially outer side of a distal end portion of the diverging section 31d of the drive-side nozzle 31 at a location on a downstream portion of the suction chamber 321a. Therefore, the coolant passage of the suction-side nozzle 322 is formed between an outer circumferential surface of the diverging section 31d and an inner circumferential surface of the body 32 and has an annular cross-section.

[0039] An outer circumferential portion of the diverging section 31d of the drive-side nozzle 31 has an outer diameter that progressively increases towards the downstream side in the coolant flow direction, similar to the coolant passage formed on the inside of the diverging section 31, as previously described. Therefore, the annular coolant passage of the suction-side nozzle 322 has a cross-sectional area that progressively decreases towards the downstream side in the coolant flow direction. That is, a so-called converging nozzle is used in the ejector 13 as the suction-side nozzle 322.

[0040] A suction-side injection port 322a of the suction-side nozzle 322 is open around the drive-side inlet port 31e and has an annular cross-section. The drive-side injection port 31e and the suction-side injection port 322a are open on a common plane. An outer diameter of the suction-side injection port 322 corresponds to a mixing section with an inlet diameter Dmix, which is an inner diameter of an inlet (coolant inlet) of the mixing section 323.

[0041] Therefore, the drive-side injection port 31e and the suction-side injection port 322a are opened such that the drive-side injection coolant immediately after being injected from the drive-side injection port 31e and the suction-side injection coolant immediately after being injected from the suction-side injection port 322a flow essentially in parallel. In other words, the drive-side injection port 31e and the suction-side injection port 322a are opened such that the injection direction of the drive-side injection coolant immediately after injection and the injection direction of the suction-side injection coolant immediately after injection coincide.

[0042] The expansion capacity of the drive-side nozzle 31 and the expansion capacity of the suction-side nozzle 322 are determined such that the pressure of the drive-side injection coolant immediately after it is injected from the drive-side injection port 31e is higher than the pressure of the suction-side injection coolant immediately after it is injected from the suction-side injection port 322a.

[0043] In particular, the drive-side injection connection cross-sectional area Anzout of the drive-side nozzle 31 and a suction-side injection connection cross-sectional area Asnout of the suction-side nozzle 322 are determined such that they satisfy the following equation F2. 2≤Asnout / Anzout≤4

[0044] The suction-side injection port cross-sectional area Asnout is a through-cross-sectional area of ​​the suction-side injection port 322a.

[0045] According to equation F2, the drive-side injection port cross-sectional area Anzout is smaller than the suction-side injection port cross-sectional area Asnout. However, the drive-side coolant is a high-pressure coolant discharged from radiator 12, and the suction-side coolant is a low-pressure coolant discharged from evaporator 16. Therefore, if the suction-side injection port cross-sectional areas Asnout and the drive-side injection port cross-sectional areas Anzout are determined to satisfy equation F2, the pressure of the drive-side injection coolant can be made higher than the pressure of the suction-side injection coolant.

[0046] The mixing section 323 forms a mixing chamber 323a in which the drive-side injection coolant and the suction-side injection coolant are mixed together. Within the body 32, the mixing section 323 is located on the downstream side of the drive-side injection port 31e and the suction-side injection port 322a in the coolant flow direction. The mixing chamber 323a is essentially shaped in a frustoconical form, and its cross-sectional area increases progressively towards the downstream side in the coolant flow direction.

[0047] In the mixing section 323, the drive-side injection coolant and the suction-side injection coolant are mixed together such that the pressure of the mixed coolant measured at the central axis of the mixing section 323 and the pressure of the mixed coolant measured at the wall surface of the mixing section 323 are identical when the mixed coolant flows out of the mixing section 323. In the mixing section 323, the drive-side injection coolant and the suction-side injection coolant are mixed such that the mixed coolant discharged from the mixing section 323 has a uniform pressure without creating a pressure gradient in the mixed coolant.Furthermore, the drive-side injection coolant and the suction-side injection coolant are mixed in the mixing section 323 in such a way that the flow velocity of the mixed coolant, which is in the gas-liquid two-phase state and flows out of the mixing section 323 and into the diffuser section 324, becomes subsonic.

[0048] Here, on the downstream side of the mixing section 323 of the ejector 13, the cross-sectional area of ​​the passage is not reduced towards the downstream side of the coolant flow direction. Therefore, the mixed coolant, which is in a gas-liquid two-phase state and has a uniform pressure and subsonic velocity, is not accelerated back to supersonic velocity on the downstream side of the mixing section 323 in the coolant flow direction.

[0049] Therefore, the shock wave is not generated on the downstream side of the mixing section 323 in the coolant flow direction. That is, the flow shape of the mixing section 323 is adjusted such that the shock wave generated by the drive-side injection coolant, which is injected at supersonic speed from the drive-side nozzle 31, is canceled out on the inside of the mixing section 323.

[0050] In particular, the flow path of the mixing section 323 is set such that the mixing section distance L satisfies the following equation F3. The relaxation distance Lv is defined by the following equation F4. Level <L Lv=U0×(ρL×DL2) / (18×μG)

[0051] The mixing section distance L is an axial length from the inlet to the outlet of the mixing section 323.

[0052] In equation F4, U0 is a mean mass velocity of the mixed coolant at the most upstream part of the initial shock wave (also referred to as a first shock wave), which is initially generated by the drive-side injection coolant in the mixing section 323. Furthermore, ρ L a density of liquid droplets of the liquid-phase coolant (hereinafter referred to as liquid droplets) contained in the mixed coolant at the most upstream part of the initial shock wave. Furthermore, D L a mean diameter of the liquid droplets contained in the mixed coolant at the most upstream part of the initial shock wave.

[0053] Furthermore, µ Ga viscosity of the gas phase coolant contained in the mixed coolant at the most upstream part of the initial shock wave.

[0054] As indicated by equation F4, the relaxation distance Lv is a distance obtained by multiplying the mean mass velocity U0 of the mixed coolant, measured at the most upstream part of the initial shock wave, by a dimensionless relaxation time expressed as a ratio between an inertial force and the viscosity of the liquid droplets. The relaxation distance Lv represents a distance obtained by multiplying an initial velocity of the mixed coolant, measured at the most upstream part of the shock wave, by the time interval required for the velocity of the liquid droplets in the mixed coolant to equalize with the velocity of the gaseous coolant in the mixed coolant.

[0055] To cancel out the initial shock wave generated by the drive-side injection coolant within the mixing section 323, the mixing section distance L must therefore be at least longer than the relaxation distance Lv. That is, the equation F3 above must be satisfied.

[0056] If an initial Mach number M0, which is a Mach number of the mixed coolant, is relatively high as measured at the most upstream part of the initial shock wave, an expansion wave can be generated on the downstream side of the initial shock wave. When the expansion wave is generated on the downstream side of the shock wave, the coolant flow velocity at the center axis of the mixing section 323 becomes subsonic. However, at this time, the coolant flow velocity at the turbulent boundary layer becomes supersonic again.

[0057] As a result, the coolant pressure, measured at the central axis of the mixing section 323, and the coolant pressure, measured at the wall surface of the mixing section 323, can change to different values, and a pseudo-shock wave phenomenon, in which multiple shock waves are regenerated, can occur. When the pseudo-shock wave is generated, multiple shock waves are generally produced until the fluid flow velocity on the downstream side of the expansion wave becomes subsonic. The pseudo-shock wave causes an energy loss of the coolant flowing into the ejector due to entropy generation by the shock wave and an increase in the frictional loss in the coolant generated by the expansion wave.

[0058] As schematically in Fig. As shown in Figure 3, the pseudo-shock wave is roughly divided into a shock wave region and a mixing region. The shock wave region is a region in which the relationship between the fluid pressure Pmi at the central axis of the fluid passage and the fluid pressure Pmo at the wall surface changes periodically, fluctuating between high and low. The mixing region is a region in which the fluid pressure Pmi at the central axis of the mixing section and the fluid pressure Pmo at the wall surface are essentially equal and change synchronously.

[0059] Fig. Figure 3 is an explanatory diagram that schematically shows a generation mode of the pseudoshock wave that is generated in the gas-phase fluid flowing in a fluid channel of a cylindrical tube 100, along an axial sectional view of the cylindrical tube 100, and a change in the fluid pressure. An unhatched area in the cylindrical tube 100 consists of Fig. 3 is an area where the fluid traveling at hypersonic speeds is predominantly distributed. A dotted-hatched area is an area where the fluid traveling at subsonic speeds is predominantly distributed.

[0060] In Fig. 3. Thick lines in cylindrical line 100 indicate shock waves, and double-dashed lines in cylindrical line 100 indicate expansion waves. Although in Fig. Although three shock waves and three expansion waves are schematically represented, the number of shock waves and the number of expansion waves are not limited to these numbers. Furthermore, the pseudo-shock wave is not a phenomenon that always occurs, and the pseudo-shock wave is not generated when the initial Mach number M0 is relatively low.

[0061] The pseudo-shock wave is generally known as a phenomenon confirmed for vapor ejectors. A vapor ejector is an ejector in which a gas-phase fluid flows within the ejector while an outlet of a diffuser section is open to the atmosphere. Vapor ejectors are used in vacuum exhaust devices, smoke extraction devices, aircraft air intakes, etc.

[0062] With reference to this phenomenon, the inventors of the present application have confirmed, as a result of checks and tests, that the pseudo-shock wave is also generated in the ejector through which the gas-liquid two-phase fluid flows. Furthermore, the inventors of the present application have confirmed that the generation mode of the pseudo-shock wave generated by the vapor ejector is different from the generation mode of the pseudo-shock wave generated by the ejector through which the gas-liquid two-phase fluid flows.

[0063] In the following description, the pseudo-shock wave generated in the vapor ejector through which the gas-phase fluid flows will, for clarity, be referred to as the pseudo-shock wave in the gas-phase flow. Furthermore, the pseudo-shock wave generated in the ejector through which the gas-liquid two-phase fluid flows will be referred to as the pseudo-shock wave in the two-phase flow.

[0064] The reason the generation mode of the pseudo-shock wave in gas-phase flow and the generation mode of the pseudo-shock wave in two-phase flow differ is the presence of liquid droplets in the gas-liquid two-phase fluid. Specifically, in the shock wave, the gas-phase coolant rapidly reduces the flow velocity, but the liquid droplets have inertial forces, so the velocity reduction is slower than that of the gas-phase coolant. In the expansion wave, the gas-phase coolant also rapidly increases the flow velocity, but the droplets increase the flow velocity more slowly than the gas-phase coolant due to the suction effect of the gas-phase coolant.

[0065] Furthermore, it was found that the pseudo-shock wave is less likely to be generated in the two-phase flow when the dryness level of the drive-side injection coolant is reduced. This is because the liquid droplets dampen the pressure wave through scattering and absorption. Therefore, the generation mode of the pseudo-shock wave in the two-phase flow changes depending on the size and number density of the liquid droplets.

[0066] Therefore, the inventors of the present application have carried out an investigation to rapidly eliminate the pseudo-shock wave in the two-phase flow when the pseudo-shock wave in the two-phase flow is generated in the mixing section 323 in the ejector 13.

[0067] One result of this investigation, as in Fig. As shown in Figure 4, it was found that the axial length required to cancel the pseudo-shock wave in the two-phase flow increases as the initial Mach number M0 increases. Furthermore, it was found that the axial length required to cancel the pseudo-shock wave in the two-phase flow increases as the degree of dryness X of the coolant flowing through the mixing section 323 increases. Fig. 4 is the axial length required to extinguish the pseudoshock wave, expressed as a ratio to the relaxation distance Lv.

[0068] In the ejector used in the ejector refrigeration cycle, it was found that the pseudo-shock wave within the mixing section can be eliminated by determining the relationship between the mixing section distance L and the relaxation length Lv, such that the following equation F5 is satisfied. 1 <L / Lv≤3,5(unter der Bedingung 1 <M0<2,5)

[0069] Furthermore, it was found that if the relationship given by equation F5 is converted into the flow transition form, the pseudo-shock wave within the mixing section can be eliminated by determining the relationship between the mixing section distance L and the mixing section inlet diameter Dmix, such that the following equation F6 is satisfied. 1 <L / Dmix≤10(unter der Bedingung 1 <M0<2,5)

[0070] Here, the mixing section inlet diameter Dmix is ​​a diameter of the coolant passage at the inlet of the mixing section 323.

[0071] The mixing section inlet diameter Dmix corresponds to the outside diameter of the suction-side injection port 322a of the suction-side nozzle 322. Furthermore, a range of the initial Mach number M0 in equations F5 and F6 is a range that can be obtained in actual use in an ejector employed in a conventional ejector refrigeration cycle.

[0072] The mixing section distance L of mixing section 323 of ejector 13 is determined such that it satisfies the equations F3, F5, and F6 above. Therefore, in mixing section 323, not only is the pressure of the mixed coolant increased, but the flow velocity of the mixed coolant is also significantly reduced. As a result, the coolant can easily detach from the wall surface of mixing section 323. This detachment of the coolant from the wall surface of mixing section 323 impedes the flow of the mixed coolant and causes energy loss.

[0073] Therefore, the shape of the mixing section 323 is adjusted such that the cross-sectional area increases towards the downstream side in the flow direction of the mixed coolant. In particular, the shape of the mixing section 323 is adjusted such that the cross-sectional area change rate dA / dz is determined to satisfy equation F7, within a range that also satisfies equations F5 and F6 above. 0 <dA / dz≤0,8(mm)

[0074] Here, the cross-sectional area change rate dA / dz is a change quantity dA (mm²). 2 ) of the coolant passage cross-sectional area per unit length dz (mm) in the axial direction of the mixing section 323. In addition, the cross-sectional area change rate dA / dz is increased in the mixing section 323 towards the downstream side in the flow direction of the coolant.

[0075] The diffuser section 324 forms a pressure boosting passage 324a for converting the kinetic energy of the mixed coolant, which is mixed in the mixing section 323, into pressure energy. The inlet of the pressure boosting passage 324a is designed to be through-connected to the outlet of the mixing section 323. The pressure boosting passage 324a is essentially shaped in a frustoconical form and increases its cross-sectional area towards the downstream side in the direction of coolant flow. This shape reduces the flow velocity of the mixed coolant in the diffuser section 324 and increases its pressure.

[0076] Furthermore, the shape of the pressure boosting passage 324a is determined such that the flow velocity of the mixed coolant flowing out of the mixing section 323 and into the diffuser section 324 becomes subsonic.

[0077] In particular, the flow shape of the diffuser section 324 is set such that the relationship between the mixing section outlet cross-sectional area Amixout and a diffuser section outlet cross-sectional area Aout satisfies the following equation F8. 0.3≤Amixout / Aout≤0.6

[0078] Here, the mixing section outlet cross-sectional area Amixout is a through-cross-sectional area of ​​the outlet of mixing section 323. The mixing section outlet cross-sectional area Amixout coincides with the through-cross-sectional area of ​​the inlet of diffuser section 324. Furthermore, the diffuser section outlet cross-sectional area Auot is a through-cross-sectional area of ​​the outlet of diffuser section 324.

[0079] In the ejector used in the ejector refrigeration cycle, the refrigerant flowing out of the diffuser section has a specific flow velocity to reduce the compressor's energy consumption. In a typical ejector refrigeration cycle, the flow velocity of the refrigerant flowing out of the diffuser section can be set to a subsonic speed of approximately 0.1 to 0.2 times the speed of sound.

[0080] Therefore, as long as the cross-sectional area of ​​the diffuser section 323 is expanded in a manner that satisfies the equation F8 above, the flow velocity of the mixed coolant flowing out of the mixing section 323 and into the diffuser section 324 will not exceed the speed of sound.

[0081] As in Fig. Figure 1 shows an inlet of a collector 14 connected to the outlet of the diffuser section 324. The collector 14 is a gas-liquid separator for separating the gas-phase and liquid-phase coolant contained in the coolant flowing from the diffuser section 324. Furthermore, the collector 14 acts as a liquid reservoir for storing a portion of the separated liquid-phase coolant as excess coolant in the circuit.

[0082] A suction port of the compressor 11 is connected to the gas-phase refrigerant outlet of the receiver 14. A refrigerant inlet of the evaporator 16 is connected to the liquid-phase refrigerant outlet of the receiver 14 by a fixed throttle 15, which serves as an expansion device. The fixed throttle 15 can be an opening, a capillary tube, or the like.

[0083] The evaporator 16 is a heat-absorbing heat exchanger that transfers heat between the low-pressure refrigerant, which is expanded through the fixed throttle 15, and the blown air, which is blown into the passenger compartment by an internal fan wheel 16a, in order to evaporate the low-pressure refrigerant and cool the blown air. The internal fan wheel 16a is an electric fan whose rotational speed (for example, a blowing capacity) is controlled by a control voltage output by the control device 20. The refrigerant outlet of the evaporator 16 is connected to the refrigerant suction port 321 of the ejector 13.

[0084] An electrical control device for the ejector refrigeration circuit 10 is then described. The control device 20 includes a known microcomputer comprising a CPU, a ROM, and a RAM, as well as peripheral circuitry. The control device 20 performs various calculations and processing operations based on an air handling control program stored in the ROM and controls the operation of the various control subject devices 11, 12a, and 16a, which are connected to an output interface of the control device 20.

[0085] Several sensors, such as an indoor air temperature sensor, an outdoor air temperature sensor, a solar radiation sensor, an evaporation temperature sensor, and a discharge pressure sensor, which are intended for air treatment control, are connected to an input side of the control device 20. Measured values ​​from these sensors are input to the control device 20.

[0086] More precisely, the interior air temperature sensor is an air temperature sensing device that detects the temperature of the passenger compartment. The exterior air temperature sensor is an outdoor air temperature sensing device that detects the outside air temperature. The solar radiation sensor is a solar radiation quantity sensing device that detects the amount of solar radiation in the passenger compartment. The evaporation temperature sensor is an evaporation temperature sensing device that detects the discharge air temperature (evaporation temperature) of the evaporator 16. The discharge pressure sensor is a discharge coolant pressure sensing device that detects the pressure of the coolant discharged by the compressor 11.

[0087] Furthermore, a control panel (not shown), located near an instrument panel at the front of the vehicle cab, is connected to the input side of the control device 20. Operating signals output by various control switches provided on the control panel are input to the control device 20. These various control switches include an air conditioning activation switch for requesting the operation of the vehicle cab air conditioning system, a vehicle cab temperature setting switch for adjusting the vehicle cab temperature, and the like.

[0088] The control device 20 is integral with control units for controlling the operation of various control subject devices, which are connected to the output side of the control device 20. In the control device 20, a structure for controlling the operation of each control subject device (for example, hardware and software) represents a corresponding control unit of the control subject device. For example, a structure for controlling the operation of compressor 11 forms a defense capacity control unit.

[0089] In Fig. Figure 1 and the like are shown as electrical power lines or signal lines for connecting the control device 20 to each of the different control subject devices, but for the sake of clarity of representation, the sensors and the signal lines for connecting the control device 20 to the sensors have been omitted.

[0090] The operation of the ejector refrigeration circuit 10 of the present embodiment is then described. When the air preparation activation switch of the control panel is switched on, the control device 20 operates the compressor 11, the cooling fan wheel 12a, the internal fan wheel 16a, and the like. The compressor 11 thus draws in and compresses the refrigerant and discharges the compressed refrigerant.

[0091] The high-temperature, high-pressure coolant discharged from compressor 11 flows into radiator 12. This high-pressure coolant transfers heat to the outside air blown by cooling fan 12a and condenses. The coolant that condenses in radiator 12 flows into the drive-side inlet 31a of the drive-side nozzle 31 of ejector 13 as the drive-side coolant. In the drive-side nozzle 31, the pressure of the drive-side coolant is reduced isentropically.

[0092] The drive-side coolant flowing into the drive-side nozzle 31 reaches a critical state in the throat section 31c, and a drive flow rate into the ejector 13 is established. The drive-side coolant is accelerated in the diverging section 31d until its flow velocity reaches supersonic speed. The drive-side injection coolant then enters a gas-liquid two-phase state and is injected from the drive-side injection port 31e into the mixing chamber 323a of the mixing section 323. The drive-side injection coolant becomes a supersonic mist stream exceeding the two-phase speed of sound.

[0093] Furthermore, the coolant flowing from the evaporator 16 is drawn into the suction chamber 321a via the suction process of the drive-side injection coolant, which is injected from the drive-side injection port 31e into the mixing section 323. This coolant flows from the evaporator 16 and is drawn into the suction chamber 321a via the coolant suction port 321. More precisely, since the drive-side injection coolant is in a gas-liquid biphase state, the injected liquid droplets are accelerated by the effect of inertial force. This reduces the pressure in the vicinity of the suction-side injection port 322a. Consequently, the suction-side coolant is drawn into the suction chamber 321a.

[0094] The suction-side coolant, which is drawn into the suction chamber 321a, is expanded at the suction-side nozzle 322, and this suction-side injection coolant is injected from the suction-side injection port 322a into the mixing chamber 323a of the mixing section 323. The pressure of the drive-side injection coolant injected into the mixing section 323 is higher than the pressure of the suction-side injection coolant injected into the mixing section 323. Therefore, the drive-side coolant undergoes subexpansion in the drive-side nozzle 31 to generate the expansion wave in the mixing section 323.

[0095] The expansion wave generated by the drive-side injection coolant is reflected at the wall surface of the mixing section 323 and a turbulent boundary layer within the mixing section 323, thus generating a shock wave in the mixing section 323. In the mixing section 323, the pressure of the mixed coolant (for example, the mixture of the drive-side and suction-side injection coolants) is increased due to the pressure recovery process of the shock wave generated by the drive-side coolant. Furthermore, in the mixing section 323, the drive-side and suction-side injection coolants are mixed to form the mixed coolant, which is in a gas-liquid biphase state and has a uniform pressure and subsonic velocity.

[0096] The mixed coolant flowing out of the mixing section 323 flows into the diffuser section 324. In the diffuser section 324, the kinetic energy of the mixed coolant is converted into pressure energy due to the expansion of the flow cross-section of the diffuser section 324. Therefore, the pressure of the mixed coolant is further increased.

[0097] The coolant flowing from diffuser section 324 enters the collector 14 and is separated into the gas-phase coolant and the liquid-phase coolant. The liquid-phase coolant, separated by the collector 14, is expanded through the fixed throttle 15 and flows into the evaporator 16. The coolant flowing into the evaporator 16 absorbs heat from the air blown by the internal fan wheel 16a and evaporates. This cools the blown air.

[0098] As previously described, the coolant flowing from the evaporator 16 is drawn into the coolant suction port 321 of the ejector 13 as the suction-side coolant. Conversely, the gaseous coolant, separated by means of the collector 14, is drawn into the compressor 11 and compressed again.

[0099] The ejector refrigeration circuit 10 can be operated as previously described to cool the air that is to be blown into the vehicle cabin.

[0100] In the ejector refrigeration circuit 10, the refrigerant, whose pressure is increased by means of the ejector 13, is drawn into the compressor 11. This allows the pressure of the suction refrigerant being drawn into the compressor 11 to be increased in the electric refrigeration circuit 10, compared to the conventional refrigerant circuit, where the refrigerant evaporation pressure in the evaporator and the suction refrigerant pressure in the compressor are essentially the same. Therefore, in the ejector refrigeration circuit 10, the energy consumption of the compressor 11 can be reduced, thus improving the coefficient of performance (COP) of the circuit compared to the conventional refrigerant circuit.

[0101] Since the ejector refrigeration circuit 10 of the present embodiment has the ejector 13, the high COP can be demonstrated regardless of any change in the load of the ejector refrigeration circuit 10. That is, the ejector 13 of the present embodiment can exhibit the excellent pressure amplification capacity regardless of any change in the load.

[0102] More precisely, in the ejector 13, the pressure of the drive-side injection coolant injected into the mixing section 323 is higher than the pressure of the suction-side injection coolant injected into the mixing section 323. Therefore, the drive-side coolant is underexpanded by means of the drive-side nozzle 31 to generate the shock wave in the mixing section 323, regardless of the change in load in the ejector refrigeration circuit 10. This allows the pressure of the mixed coolant to be increased, for example, by means of the pressure recovery process of the shock wave in the mixing section 323.

[0103] Furthermore, in the ejector 13, the flow velocity of the mixed coolant exiting the mixing section 323 and entering the diffuser section 324 is reduced to subsonic speed. This allows the shock wave generated by the drive-side injection coolant to be reliably extinguished in the mixing section 323. Therefore, it is possible to reduce the energy loss caused by the shock wave after the pressure recovery process.

[0104] In other words, even if the pseudo-shock wave in the two-phase flow in the mixing section 323 is generated due to the occurrence of the change in load in the ejector refrigeration circuit 10, the pseudo-shock wave can be quickly extinguished in order to limit the energy loss caused by the entropy generation of the pseudo-shock wave.

[0105] Furthermore, in the mixing section 323, the drive-side injection coolant and the suction-side injection coolant are mixed together in such a way that the pressure of the mixed coolant, measured at the central axis, and the pressure of the mixed coolant, measured at the wall surface of the mixing section 323, are identical when the mixed coolant flows out of the mixing section 323 and into the diffuser section 324. Therefore, even if the generating area of ​​the pseudo-shock wave in the two-phase flow changes due to the occurrence of a change in the load of the refrigeration circuit device, the pseudo-shock wave can be reliably canceled out in the mixing section 323.

[0106] Consequently, according to the ejector 13 of the present embodiment, it is possible to exhibit excellent pressure amplification capacity by utilizing the shock wave, regardless of changes in the load of the refrigeration circuit device. Furthermore, in the ejector 13, through which the gas-liquid two-phase refrigerant flows, the pressure wave can be dampened by the liquid droplets contained in the gas-liquid two-phase refrigerant. Therefore, even when the shock wave is used to exhibit excellent pressure amplification capacity, the generation of noise and vibration can be limited.

[0107] Furthermore, the inventors of the present application have tested a method for effectively increasing the pressure of the mixed coolant by means of the pressure recovery process of the shock wave in the ejector 13. Fig. Figure 5 is a graph showing a result of the test.

[0108] Fig. Figure 5 shows a pressure change in the ejector 13 when the coolant pressure at the outlet of the diffuser section 324 is changed, in a condition where an inlet pressure of the drive-side coolant flowing into the ejector 13, a degree of dryness X of the drive-side coolant, and a suction flow rate of the suction-side coolant are kept constant. More precisely, it shows Fig. 5 a static pressure distribution of the environment of the inner wall surface of the ejector 13 for the following four operating conditions OP1 to OP4.

[0109] Operating condition OP1 is an operating condition in which the coolant pressure at the outlet of diffuser section 324 is set to its lowest value. Operating condition OP2 is an operating condition in which the coolant pressure at the outlet of diffuser section 324 is set to be higher than that of operating condition OP1. Operating condition OP3 is an operating condition in which the coolant pressure at the outlet of diffuser section 324 is set to be higher than that of operating condition OP2. Operating condition OP4 is an operating condition in which the coolant pressure at the outlet of diffuser section 324 is set to be higher than that of operating condition OP3.

[0110] Therefore, the coolant pressure at the outlet of diffuser section 324 increases, in the order of operating condition OP1, operating condition OP2, operating condition OP3, and operating condition OP4. In the graph from Fig. 5 is a value obtained by subtracting the coolant pressure at the inlet of the mixing section 323 from the coolant pressure at the outlet of the diffuser section 324, representing the total coolant pressure increase of the ejector 13. Fig. For the sake of clarity, the pressure increase quantity ΔP is shown only for operating condition OP3.

[0111] First, under the operating condition OP1, as shown by a bold dotted line in the graph from Fig. As indicated in section 5, the pressure of the mixed coolant at the inlet of diffuser section 324 is reduced. Therefore, it is understandable that under operating condition OP1, as shown in Fig. Figure 6 shows that when the mixed coolant, which has a supersonic speed, enters the diffuser section 324, the pressure of the coolant, which has a supersonic speed, is reduced due to the progressive enlargement in the passage cross-sectional area of ​​the diffuser section 324.

[0112] Furthermore, under operating condition OP1, the total pressure increase of the ejector 13 is smaller than under the other operating conditions. Therefore, it is understandable that the pseudo-shock wave is generated in the two-phase flow and that the shock wave area extends into the diffuser section 324 to increase energy loss.

[0113] Fig. 6 is an explanatory diagram, as in Fig. Figure 3 schematically shows the generation mode of the shock wave that is generated in the coolant flowing into the ejector 13 along an axial sectional view of the ejector 13. Therefore, an unhatched area in the ejector 13 consists of Fig. 6. A region where the fluid traveling at supersonic speed is mainly distributed. A dotted hatching area is a region where the fluid traveling at subsonic speed is mainly distributed. In Fig. 3. In the cylindrical line 100, bold lines indicate the shock waves and double-dashed lines in the cylindrical line 100 indicate the expansion waves. This is also the case in Fig. 7 to 9.

[0114] The process continues under operating condition OP2, as indicated by a bold dotted line in the graph. Fig. 5, characterized by a rapid pressure increase of the mixed coolant at a downstream section of the mixing section 323. Therefore, it is understandable that under operating condition OP2 the shock wave range is shorter than that of operating conditions OP1 and the pressure recovery process by means of the shock wave begins at the downstream section of the mixing section 323.

[0115] Furthermore, under operating condition OP2, the total pressure increase of ejector 13 is increased compared to operating condition OP1. Therefore, it is understandable that under operating condition OP2, as shown in Fig. 7, the shock wave is extinguished in the mixing section 323 and the relaxation distance Lv of the pseudo-shock wave is reduced more than under the operating condition OP1, thereby reducing the energy loss.

[0116] The process continues under operating condition OP3, as indicated by a bold solid line in the graph. Fig. Figure 5 indicates a rapid pressure increase of the mixed coolant in the vicinity of the inlet of the mixing section 323. This means that the position at which the rapid pressure increase begins is shifted upstream of the position under operating condition OP2 in the coolant flow direction. Therefore, it is understandable that under operating condition OP3 the shock wave range is shorter than under operating condition OP2, and the pressure recovery process via the shock wave begins in the vicinity of the inlet of the mixing section 323.

[0117] Furthermore, under operating condition OP3, the total pressure increase of ejector 13 is increased compared to the other operating conditions. Therefore, it is understandable that under operating condition OP3, as shown in Fig. 8, the shock wave is rapidly extinguished in the mixing section 323 and the relaxation distance Lv of the pseudo-shock wave is reduced more than that of the other operating conditions, thereby further reducing the energy loss.

[0118] Furthermore, under operating condition OP4, as shown by a bold dot-dot-dash line in Fig. 5 indicates that the coolant pressure at the inlet of mixing section 323 is higher than that under other operating conditions. That is, as shown by a thin dotted line in Fig. Figure 5 indicates that the pressure of the drive-side ejection coolant is increased. A thin dotted line in Fig. 5 indicates a static pressure distribution in the drive-side nozzle 31.

[0119] Furthermore, the rapid pressure increase of the mixed coolant begins immediately after the coolant flows into the mixing section 323. Therefore, it is understandable that under operating condition OP4, as indicated in Fig. 9, the drive-side coolant cannot be underexpanded by means of the drive-side nozzle 31 and thus the shock wave is generated inside the drive-side nozzle 31.

[0120] Therefore, under operating condition OP4, the pressure recovery process of the shock wave is not sufficiently utilized to increase the pressure of the mixed coolant in the mixing section 323, and thus the overall pressure increase of the ejector 13 is also reduced compared to other operating conditions. If the coolant pressure at the inlet of the mixing section 323 is increased, as under operating condition OP4, the pressure of the suction-side coolant is also increased, potentially causing an increase in the coolant evaporation temperature in the evaporator 16.

[0121] From the preceding, it was established that, in order to effectively increase the pressure of the mixed coolant by means of the pressure recovery process of the shock wave in the mixing section 323, it is effective to reliably underexpand the drive-side coolant by means of the drive-side nozzle 31. Furthermore, it was established that it is effective to generate the initial shock wave, which is produced by means of the drive-side injection coolant, in the vicinity of the inlet of the mixing section 323. In addition, it was established that it is effective to rapidly extinguish the shock wave that is generated in the mixing section 323. That is to say, it was established that it is effective to shorten the shock wave range.

[0122] In the ejector 13 of the present embodiment, the ratio of Asnout / Anzout is set to ensure that the pressure of the drive-side injection coolant is higher than the pressure of the suction-side injection coolant, as discussed with reference to equation F2.

[0123] Accordingly, the pressure of the drive-side injection coolant can be made higher than the pressure of the suction-side injection coolant without requiring the complex operating control based on load changes. Furthermore, the expansion wave can be reliably generated in the drive-side injection coolant by reliably underexpanding the drive-side coolant through the drive-side nozzle 31.

[0124] Furthermore, in the ejector 13 of the present embodiment, as discussed with reference to equation F1, the ratio of Anzout / Anzth is adjusted to ensure that the flow velocity of the drive-side injection coolant injected from the drive-side injection port 31e is equal to or higher than the two-phase speed of sound, which is the speed of sound of the gas-liquid two-phase coolant, and that the flow velocity of the gas-phase coolant in the coolant passage of the drive-side nozzle 31 is equal to or lower than the gas-phase speed of sound, which is the speed of sound of the gas-phase coolant.

[0125] Accordingly, the flow velocity of the drive-side injection coolant in the gas-liquid two-phase state can be reliably increased to or above the two-phase speed of sound without requiring the complex operational control based on load changes. Furthermore, the flow velocity of the gas-phase coolant in the coolant passage of the drive-side nozzle 31 can be made equal to or lower than the gas-phase speed of sound.

[0126] As in Fig. As shown in Figure 10, the expansion wave can be generated from the interior of the drive-side nozzle 31 if the flow velocity of the gas-phase coolant in the coolant passage of the drive-side nozzle 31 is made equal to or lower than the gas-phase speed of sound. This occurs for the following reason: The accelerated flow generated by the expansion wave draws the gas-phase coolant, located on the radially outer side and having a flow velocity equal to or lower than the gas-phase speed of sound, into the drive-side nozzle 31. Consequently, the initial shock wave generated by the drive-side injection coolant in the mixing section 323 can be directed to the vicinity of the inlet of the mixing section 323.

[0127] According to the examination of the inventors of the present application, it was confirmed that during normal operation of the ejector refrigeration circuit 10, the distance L1, measured from the inlet of the mixing section 323 to the point of initial shock wave generation, is 0.1 times or less than the mixing section inlet diameter Dmix. Therefore, as with reference to the operating condition OP3 from Fig. As described in section 5, the overall pressure increase of the ejector 13 will be increased.

[0128] Furthermore, since the wall surface friction in the coolant passage of the drive-side nozzle 31 can be reduced, the initial Mach number M0 can be increased. Therefore, the pressure increase of the mixed coolant can be further increased by means of the shock wave, which has high energy.

[0129] Furthermore, in the ejector 13 of the present embodiment, the mixing section distance L is set to be longer than the relaxation distance Lv, as discussed with reference to equation F3. Thus, the initial shock wave generated by the drive-side injection coolant in the mixing section 323 can be effectively extinguished within the mixing section 323. Therefore, the flow velocity of the mixed coolant, which is in the gas-liquid two-phase state and flows out of the mixing section 323 and into the diffuser section 324, can easily be brought close to subsonic speed.

[0130] Furthermore, in the ejector 13 of the present embodiment, the range of L / Lv or the range of L / Dmix is ​​set, as discussed with reference to equations F5 and F6. Thus, even if the pseudo-shock wave in the two-phase flow is generated due to the occurrence in the change in the load of the ejector refrigeration circuit 10, the pseudo-shock wave in the two-phase flow can be reliably canceled out in the mixing section 323.

[0131] To eliminate the pseudo-shock wave in the two-phase flow in the mixing section 323, it is conceivable to simply adjust the mixing section distance L to be long. However, if the mixing section distance L is set to be long, the ejector 13 will become large overall.

[0132] On the other hand, equations F5 and F6 are very effective in showing the upper limit of the mixing section distance L within a range that can be realized in actual use.

[0133] Furthermore, in the ejector 13 of the present embodiment, as discussed with reference to equation F7, the flow shape of the mixing section 323 is adjusted such that the flow cross-sectional area is progressively increased towards the downstream side in the direction of coolant flow. Accordingly, the separation of the coolant in the vicinity of the wall surface of the mixing section 323 from the wall surface is limited, and thus the energy loss can be limited.

[0134] As in the present embodiment, in the ejector 13, which can rapidly increase the pressure of the mixed coolant by means of the pressure recovery process of the shock wave in the mixing section 323, the flow velocity of the mixed coolant is rapidly reduced in the mixing section 323. Therefore, it is effective in limiting the detachment of the coolant, which is in the vicinity of the wall surface of the mixing section 323, from the wall surface in order to limit energy loss.

[0135] The inventors of the present application have confirmed that the ejector 13 in the ejector refrigeration circuit 10, which uses the HFO refrigerant, the HFC refrigerant or the mixture of these refrigerants as the refrigerant of the present embodiment, has excellent pressure amplification capacity by using the shock wave under the following conditions.

[0136] In particular, it was confirmed that the ejector 13 has a pressure amplification capacity that is four times or more than that of the previously proposed technique, within a range in which at least the inlet pressure Pin and the outlet pressure Pout of the ejector 13 satisfy both of the following equations F9 and F10. 0.4≤Pin≤1.7(MPa) 0.3≤Pout≤0.65(MPa)

[0137] Here, the inlet pressure Pin is the pressure of the drive-side coolant flowing into the drive-side nozzle 31 of the ejector 13. The outlet pressure Pout is the pressure of the coolant flowing out of the diffuser section 324.

[0138] Furthermore, it was confirmed that the ejector 13 has a pressure amplification capacity that is four times or more of the previously proposed technique, within a range in which at least the inlet pressure Pin and the drive-side injection pressure Pnzout of the ejector 13 satisfy the following equation F11. 0.2≤Pnzout / Pin≤0.65

[0139] Here, the drive-side injection pressure Pnzout is a pressure of the drive-side injection coolant immediately after it has been injected from the drive-side injection port 31e.

[0140] HFO refrigerants include R1234zd and similar refrigerants, in addition to R1234yf. HFC refrigerants include R134a, R410A, R32, R404A, R407C, and similar refrigerants. A subcritical refrigeration cycle is formed in the ejector refrigeration circuit that uses one or more of these refrigerants. (Second embodiment)

[0141] The ejector 113 of the present embodiment is used in an ejector refrigeration circuit 10, which has a structure similar to that of the first embodiment. The ejector refrigeration circuit 10 of the present embodiment is used in a stationary heating and hot water supply device that heats the air blown into a room or into water to be heated as hot water. The ejector refrigeration circuit 10 of the present embodiment uses carbon dioxide as a refrigerant and forms a supercritical refrigeration circuit in which the refrigerant pressure on the high-pressure side exceeds a critical refrigerant pressure.

[0142] Therefore, a radiator 12 of the ejector refrigeration circuit 10 of the present embodiment is a heat-emitting heat exchanger that transfers heat between the high-pressure refrigerant and the air that is to be blown into the air handling unit or the water that is to be supplied to the kitchen, bathroom, or the like as hot water, in order to release the heat of the high-pressure refrigerant in a supercritical state. Furthermore, the evaporator 16 of the present embodiment is a heat-absorbing heat exchanger that transfers heat between the low-temperature refrigerant and the outside air, which is blown in by means of an outside air blower wheel to evaporate the low-pressure refrigerant and carry out a heat absorption process.

[0143] As in Fig. As shown in Figure 11, the ejector 113 of the present embodiment comprises a drive-side nozzle 131, a body 132, a needle valve 133, and a drive mechanism 134. The drive-side nozzle 131 has dimensions and properties of its respective sections that are configured to perform the same functions as those of the drive-side nozzle 31 described in the first embodiment. The needle valve 133 is located in the coolant passage of the drive-side nozzle 131.

[0144] The needle valve 133 is axially displaceable in the direction of the drive-side nozzle 131 to change the flow cross-sectional area of ​​a neck section and the flow cross-sectional area of ​​a drive-side injection port of the drive-side nozzle 131. The needle valve 133 is formed by a needle-like component made of metal (stainless steel in this embodiment). A central axis of the needle valve 133 and a central axis of the drive-side nozzle 131 are coaxial. An end section of the needle valve 133, which faces the drive-side injection port 31e, is coupled to the drive mechanism 134.

[0145] The drive mechanism 134 is a drive device that displaces the needle valve 133 in the axial direction of the central axis. In the present embodiment, a stepped motor is used as the drive mechanism 134. The operation of the drive mechanism 134 is controlled by means of a control signal (e.g., a control pulse) that is output by the control unit 20.

[0146] The body 132 is formed by combining a plurality of block components made of metal (aluminum in this embodiment). The body 132 has dimensions and properties of its respective sections that are configured to perform the same functions as those of the body 32 described in the first embodiment. Similar to the first embodiment, the body 132 has the coolant suction port 321, the suction-side nozzle 322, the mixing section 323, and the diffuser section 324.

[0147] The rest of the construction of ejector 113 is the same as that of ejector 13, which is described in the first embodiment.

[0148] The operation of the ejector refrigeration circuit 10 of the present embodiment is then described. In the present embodiment, the control device 20 controls the operation of the drive mechanism 134 such that the degree of superheat of the refrigerant at the outlet of the evaporator 16 approaches a predetermined reference degree of superheat KSH. The remainder of the operation is the same as that of the first embodiment. Therefore, the advantages, which are identical to those of the first embodiment, can be achieved with the ejector refrigeration circuit 10 of the present embodiment.

[0149] This means that the ejector 113 of the present embodiment can exhibit excellent pressure amplification capacity, regardless of any changes in load. Consequently, the high COP can also be demonstrated in the ejector refrigeration circuit 10 of the present embodiment, regardless of any changes in load.

[0150] The inventors of the present application have confirmed that the ejector refrigeration circuit 10, which uses carbon dioxide or a mixed refrigerant containing carbon dioxide as the refrigerant of the present embodiment, the ejector 113 has excellent pressure amplification capacity by using the shock wave under the following conditions.

[0151] In particular, it was confirmed that the ejector 113 has excellent pressure amplification capacity within a range in which at least the inlet pressure Pin and the outlet pressure Pout of the ejector 113 satisfy both of the following equations F12 and F13. 6≤Pin≤14(MPa) 1.5≤Pout≤7(MPa)

[0152] Furthermore, it was confirmed that the ejector 113 has excellent pressure amplification capacity within a range in which at least the inlet pressure Pin and the drive-side injection pressure Pnzout of the ejector 113 satisfy the following equation F14. 0.3≤Pnzout / Pin≤0.7

[0153] In the ejector refrigeration cycle, which uses carbon dioxide or a mixed refrigerant containing carbon dioxide, a supercritical refrigeration cycle is formed. (Third embodiment)

[0154] The present embodiment describes an example in which, as shown in Fig. 12, the ejector 13, which was previously described, is used in an ejector refrigeration circuit 10a. The ejector refrigeration circuit 10a is used in an air preparation device for a vehicle. The ejector refrigeration circuit 10a includes a branch section 17, a first evaporator 161, and a second evaporator 162. The collector 14 is removed from the ejector refrigeration circuit 10a.

[0155] The branching section 17 is a three-way connection that splits the flow of coolant discharged by the radiator 12. The drive-side inlet 31a of the drive-side nozzle 31 of the ejector 13 is connected to one of the two outlets of the branching section 17. The inlet of the fixed throttle 15 is connected to the other of the two outlets of the branching section 17.

[0156] The coolant inlet of the first evaporator 161 is connected to the outlet of the diffuser section 324 of the ejector 13. The first evaporator 161 is a heat-absorbing heat exchanger that transfers heat between the low-pressure coolant discharged from the diffuser section 324 of the ejector 13 and the blown air, which is drawn by the internal fan wheel 16a to cool the blown air. The suction port of the compressor 11 is connected to a coolant outlet of the first evaporator 161.

[0157] A coolant inlet of the second evaporator 162 is connected to an outlet of the fixed throttle 15. The second evaporator 162 is a heat-absorbing heat exchanger that transfers heat between the low-pressure coolant, which is expanded through the fixed throttle 15, and the blown air that has passed through the first evaporator 161 to cool the blown air. The coolant suction port 321 of the ejector 13 is connected to a coolant outlet of the second evaporator 162.

[0158] The first evaporator 161 and the second evaporator 162 of the present embodiment are integrally formed. In particular, the first evaporator 161 and the second evaporator 162 are each formed by means of a so-called shell-and-tube heat exchanger. The shell-and-tube heat exchanger is a heat exchanger having a plurality of tubes for circulating the refrigerant and a pair of collection / distribution tanks, each connected to two ends of the respective tubes, for collecting or distributing the refrigerant.

[0159] The first evaporator 161 and the second evaporator 162 are integrally formed by creating a pair of collection / distribution tanks as common components shared by both the first evaporator 161 and the second evaporator 162. In the present embodiment, the first evaporator 161 and the second evaporator 162 are arranged in series in the direction of airflow such that the first evaporator 161 is located on the upstream side of the second evaporator 162 in the direction of airflow. Therefore, the airflow, as indicated by a thin dotted line arrow in Fig. It is marked 12.

[0160] The rest of the construction of the ejector refrigeration circuit 10a and the ejector 13 is the same as that of the first embodiment.

[0161] The operation of the ejector refrigeration circuit 10a of the present embodiment is then described. When the control device 20 operates the compressor 11 in the ejector refrigeration circuit 10a, the high-temperature, high-pressure refrigerant discharged by the compressor 11 is condensed in the radiator 12 as in the first embodiment. The refrigerant flowing out of the radiator 12 enters the branching section 17. The branching section 17 divides the flow of refrigerant discharged from the radiator 12.

[0162] The coolant discharged from one of the two outlets of the branching section 17 flows into the drive-side inlet 31a of the drive-side nozzle 31 of the ejector 13 as the drive-side coolant. In the drive-side nozzle 31, as in the first embodiment, the drive-side coolant expands isentropically. Then, the drive-side injection coolant, which is in a gas-liquid two-phase state and has a flow velocity exceeding the two-phase speed of sound, is injected from the drive-side injection port 31e of the drive-side nozzle 31 into the mixing chamber 323a of the mixing section 323.

[0163] Furthermore, by means of the suction process of the drive-side injection coolant, the coolant flowing from the second evaporator 162 is drawn from the coolant suction port 321 into the suction chamber 321a as the suction-side coolant. The suction-side coolant drawn into the suction chamber 321a flows into the suction-side nozzle 322. In the suction-side nozzle 322, as in the first embodiment, the suction-side injection coolant is injected from the suction-side injection port 322a of the suction-side nozzle 322 into the mixing chamber 323a of the mixing section 323.

[0164] In the mixing section 323, the pressure of the mixed coolant (for example, the mixture of drive-side injection coolant and suction-side injection coolant) is increased due to the pressure recovery process of the shock wave generated by the drive-side injection coolant. The mixed coolant flowing out of the mixing section 323 flows into the diffuser section 324. In the diffuser section 324, as in the first embodiment, the pressure of the mixed coolant is further increased.

[0165] The refrigerant flowing from diffuser section 324 enters the first evaporator 161. In the first evaporator 161, the refrigerant output from diffuser section 324 absorbs heat from the air blown by the internal fan wheel 16a and evaporates. This cools the blown air. The gaseous refrigerant output from the first evaporator 161 is drawn into compressor 11 and compressed again.

[0166] Furthermore, the coolant discharged from the other outlet of branch section 17 flows into the fixed throttle 15 and is isentropically expanded. The low-pressure coolant, expanded through the fixed throttle 15, flows into the second evaporator 162. The coolant flowing into the second evaporator 162 absorbs heat from the blown air that has passed through the first evaporator 161 and evaporates. Therefore, the blown air is further cooled and blown into the vehicle cabin. The coolant discharged from the second evaporator 162 is drawn into the coolant suction port 321 of the ejector 13.

[0167] The ejector refrigeration circuit 10a of the present embodiment can be operated as previously described to cool the air that is to be blown into the vehicle cabin.

[0168] In the ejector refrigeration circuit 10a, the refrigerant evaporation temperature of the first evaporator 161 can be increased to above the refrigerant evaporation temperature of the second evaporator 162 by means of the pressure intensification process of the ejector 13. Therefore, in the ejector refrigeration circuit 10a, the temperature difference between the refrigerant evaporation temperature of the first evaporator 161 and the temperature of the blown air, and the temperature difference between the refrigerant evaporation temperature of the second evaporator 162 and the temperature of the blown air, can be ensured, and thus the blown air can be effectively cooled.

[0169] Furthermore, the high COP can be demonstrated in the ejector refrigeration circuit 10a of the present embodiment, since the ejector 13 is used regardless of the occurrence of the change in the load of the ejector refrigeration circuit 10a.

[0170] The present invention is not limited to the embodiments described above and can be modified in various ways as follows within the scope of the following patent claims.

[0171] In the embodiments described above, the ejector 13, 113 of the present disclosure is used in an ejector refrigeration circuit 10, 10a. However, the circuit in which the ejector 13, 113 of the present disclosure can be used is not limited to such an ejector refrigeration circuit 10, 10a. For example, the ejector 13, 113 of the present disclosure can be used in a circuit in which an intermediate pressure expansion valve is added to the ejector refrigeration circuit 10.

[0172] In the ejector refrigeration circuit 10, the intermediate pressure expansion valve expands the coolant discharged by the radiator 12 and discharges the expanded coolant to the drive-side inlet 31a of the drive-side nozzle 31 of the ejector 13. A variable throttle mechanism can be used as the intermediate pressure expansion valve, which changes its throttle opening degree such that the pressure of the high-pressure coolant flowing into the intermediate pressure expansion valve becomes a target high pressure, determined based on the temperature of the high-pressure coolant.

[0173] Furthermore, the ejector 13, 113 of the present disclosure can be used in a circuit in which an intermediate pressure expansion valve is added to the ejector refrigeration circuit 10a.

[0174] In the ejector refrigeration circuit 10a, the intermediate pressure expansion valve expands the refrigerant discharged from the radiator 12 and discharges the expanded refrigerant to the flow inlet of the branching section 17. A variable throttling mechanism can be used as the intermediate pressure expansion valve, which changes the throttle opening degree so that the degree of superheat of the refrigerant discharged from the first evaporator 161 approaches a predetermined reference degree of superheat.

[0175] Furthermore, in the third embodiment described above, the first evaporator 161 and the second evaporator 162 of the ejector refrigeration circuit 10a are integrally formed. Alternatively, the first evaporator 161 and the second evaporator 162 can be formed separately. In this case, the first evaporator 161 and the second evaporator 162 can cool different cooling fluids, each within different temperature ranges.

[0176] Since the ejector 13, 113 exhibits excellent pressure amplification capacity, regardless of any changes in load, the first evaporator 161, which has a higher refrigerant evaporation temperature than the second evaporator 162, can be used to condition the air that is to be blown into the air conditioning subject chamber. The second evaporator 162, which has a lower refrigerant evaporation temperature than the first evaporator 161, can be used to cool the blown air that is recirculated and blown into the cooler.

[0177] The design of the ejector refrigeration circuit 10, 10a is not limited to those described in the embodiments above.

[0178] For example, compressor 11 is not limited to an electric compressor. For instance, if the ejector refrigeration circuit 10, 10a is used in a vehicle with an internal combustion engine, a motor-driven compressor can be used, driven by a rotary force transmitted from the internal combustion engine. In the ejector refrigeration circuit, a variable compression compressor can be used as the motor-driven compressor, which can change the refrigerant discharge capacity by changing the discharge volume.

[0179] A so-called sub-cooling condenser can be used as the radiator 12 of the ejector refrigeration cycle, which forms a subcritical refrigeration cycle.

[0180] The subcooling condenser comprises a condensing unit, a receiver, and a subcooling unit. The condensing unit condenses the refrigerant by transferring heat between the refrigerant and the ambient air. The receiver separates the refrigerant discharged from the condensing unit into the gaseous and liquid phases, and stores a portion of the separated liquid phase refrigerant as excess refrigerant for the circuit. The subcooling unit subcools the liquid phase refrigerant by transferring heat between the liquid phase refrigerant discharged from the receiver and the ambient air.

[0181] Furthermore, the components disclosed in the above embodiments can be combined to a practical extent. For example, the ejector 113 described in the second embodiment can be used in the ejector refrigeration circuit 10a described in the third embodiment.

[0182] Although the present invention has been described with reference to the embodiments and modifications, it is understood that the present invention is not limited to the embodiments, modifications, and structures described herein. The present invention also includes various variants and variations within the scope of the following claims.

Claims

[1] Ejector for use in a refrigeration circuit device, comprising: a drive-side nozzle (31) designed to expand a drive-side coolant and accelerate it to a supersonic speed and inject the drive-side coolant as a drive-side injection coolant in a gas-liquid two-phase state; and a body (32) which includes: a coolant suction port (321) designed to draw suction-side coolant; a suction-side nozzle (322) designed to expand and inject the suction-side coolant, which is drawn in as suction-side injection coolant through the coolant suction port (321); a mixing section (323) designed to mix the suction-side injection coolant injected from the suction-side nozzle (322) and the drive-side injection coolant injected from the drive-side nozzle (31); and a diffuser section (324) designed to convert kinetic energy of the mixed coolant formed from the suction-side injection coolant and the drive-side injection coolant mixed in the mixing section (323) into pressure energy, wherein: the drive-side nozzle (31) has a converging section (31b), a neck section (31c) and a diverging section (31d), wherein the diverging section (31d) has a passage cross-sectional area for the passage of the coolant, which is progressively enlarged from the neck section (31c) to a drive-side injection port (31e); the drive-side nozzle (31) is arranged coaxially in a cylindrical space formed on an inside of the body (32); a coolant passage of the suction-side nozzle (322) is formed between an outer circumferential surface of the diverging section (31d) and an inner circumferential surface of the body (32) and has a cross-section that is formed in an annular shape; the drive-side injection port (31e) of the drive-side nozzle (31) and a suction-side injection port (322a) of the suction-side nozzle (322) are open such that an injection direction of the drive-side injection coolant injected by the drive-side injection port (31e) and an injection direction of the suction-side injection coolant injected by the suction-side injection port (322a) coincide; a pressure of the drive-side injection coolant is higher than a pressure of the suction-side injection coolant; and when the mixed coolant flows out of the mixing section (323) and into the diffuser section (324), a pressure of the mixed coolant measured on a central axis of the mixing section (323) and a pressure of the mixed coolant measured on a wall surface of the mixing section (323) are equal, while a flow velocity of the mixed coolant is a subsonic velocity. [2] Ejector according to claim 1, wherein a through-cross-sectional area of ​​an outlet of the mixing section (323) is defined as a mixing section outlet cross-sectional area Amixout and a through-cross-sectional area of ​​an outlet of the diffuser section (324) is defined as a diffuser section outlet cross-sectional area Aout; and A ratio of Amixout / Aout is set to ensure that the flow velocity of the mixed coolant flowing into the diffuser section (324) becomes subsonic. [3] Ejector according to claim 1 or 2, wherein: an axial length measured from an inlet to an outlet of the mixing section (323) is defined as a mixing section distance L, and an axial length required to extinguish a shock wave generated by the drive-side injection coolant in the mixing section (323) is defined as a relaxation distance Lv; The mixing section distance L and the relaxation distance Lv are set to Lv <L zu erfüllen; und The relaxation distance Lv is defined using the following equation: Lv=U0×(ρL×DL2) / (18×μG), where: U0 is the mean mass velocity of the mixed coolant at the most upstream part of the shock wave; ρ L a density of liquid droplets contained in the mixed coolant at the most upstream part of the shock wave; D L a diameter of the liquid droplets contained in the mixed coolant at the most upstream part of the shock wave; and µ G a viscosity of a gas phase coolant contained in the mixed coolant at the most upstream part of the shock wave. [4] Ejector according to claim 3, wherein: a Mach number of the mixed coolant at the most upstream part of the shock wave is defined as an initial Mach number M0; and the initial Mach number M0 in a range of 1 <m0<2,5 ist und die mischabschnittsentfernung l relaxationsentfernung lv eingestellt sind, um 1<l lv≤3,5 zu erfüllen.[5] Ejector according to claim 3, wherein: a Mach number of the mixed coolant at the most upstream part of the shock wave is defined as an initial Mach number M0 and a diameter of the inlet of the mixing section (323) is defined as a mixing section inlet diameter Dmix; and the initial Mach number M0 in a range of 1 <m0<2,5 ist und die mischabschnittsentfernung l der mischabschnitteinlassdurchmesser dmix eingestellt sind, um 1<l dmix≤10 zu erfüllen.[6] Ejector according to claim 4 or 5, wherein a cross-sectional area of ​​the mixing section (323) is progressively increased towards a downstream side in a flow direction of the mixed coolant. [7] Ejector according to any one of claims 1 to 6, wherein the drive-side nozzle (31) is designed to accelerate gas phase coolant in a coolant passage formed at an interior of the drive-side nozzle (31) to a flow velocity equal to or lower than a gas phase sound velocity. [8] Ejector according to claim 7, wherein: the neck section (31c) has a passage cross-sectional area which is smallest in the drive-side nozzle (31); the through-cross-sectional area of ​​the neck section (31c) is defined as a neck section cross-sectional area Anzth and a through-cross-sectional area of ​​the drive-side injection port (31e) is defined as a drive-side injection port cross-sectional area Anzout; and A ratio of Anzout / Anzth is set to ensure that the flow velocity of the gas phase coolant in the coolant passage is equal to or lower than the gas phase sound velocity. [9] Ejector according to any one of claims 1 to 8, wherein: a through-cross-sectional area of ​​the drive-side injection port (31e) is defined as a drive-side injection port cross-sectional area Anzout and a through-cross-sectional area of ​​the suction-side injection port (322a) is defined as a suction-side injection port cross-sectional area Asnout; and A ratio of Asnout / Anzout is set to ensure that the pressure of the drive-side injection coolant is higher than the pressure of the suction-side injection coolant.

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