WO2021261112A1 - Ejector - Google Patents

Abstract

This ejector is provided with: a drive-side nozzle part (31, 131); and a body part (32,132). The body part (32, 132) has a refrigerant sucking port (321), a sucking-side nozzle portion (322), a mixing portion (323), and a diffuser portion (324). A drive-side jetting port (31e) of the drive-side nozzle part (31, 131) and a sucking-side jetting port (322a) of the sucking-side nozzle portion (322) are opened so that the jetting direction of a drive-side jetted refrigerant and the jetting direction of a sucking-side jetted refrigerant are to be equivalent. The pressure of the drive-side jetted refrigerant is higher than the pressure of the sucking-side jetted refrigerant. The mixed refrigerant flowing from the mixing portion (323) to the diffuser portion (324) has a subsonic speed, and the refrigerant pressure thereof on the central axis side coincides with the refrigerant pressure on the wall surface side.

Description

Ejector Cross-reference of related applications

This application is based on Japanese Patent Application No. 2020-107080 filed on June 22, 2020, and the contents of the description are incorporated herein by reference.

The present disclosure relates to an ejector that injects a fluid in a gas-liquid two-phase state from a nozzle portion on the drive side.

Conventionally, an ejector type refrigeration cycle, which is a refrigeration cycle device equipped with an ejector, is known.

In the ejector type refrigeration cycle, the pressure of the refrigerant sucked into the compressor can be raised higher than the refrigerant evaporation pressure in the evaporator by the pressurizing action of the ejector. As a result, in the ejector type refrigeration cycle, the power consumption of the compressor is reduced and the coefficient of performance (COP) of the cycle is improved. Therefore, in order to improve the COP of the ejector type refrigeration cycle, it is effective to improve the boosting capacity of the ejector.

On the other hand, in Patent Document 1, as an ejector applied to the ejector type refrigeration cycle, the passage shape of the mixing portion for mixing the injection refrigerant and the suction refrigerant is described, and the passage cross-sectional area is described as the direction of the refrigerant flow. An ejector having a truncated cone shape to be enlarged is disclosed. As a result, the ejector of Patent Document 1 attempts to suppress the energy loss of the refrigerant in the mixing portion and increase the boosting amount of the refrigerant in the diffuser portion.

Further, in Patent Document 2, in an industrial ejector (hereinafter, referred to as a steam ejector) applied to a vacuum exhaust device or the like, the gas phase fluid (specifically, air) is boosted by the pressure recovery action of a shock wave. It is stated that it will be done. Further, Patent Document 2 describes that the steam ejector can enhance the pressure recovery action of the shock wave by reducing the Mach number of air in the most upstream portion of the shock wave.

U.S. Pat. No. 9,568,220 Japanese Unexamined Patent Publication No. 59-151000

However, in the ejector of Patent Document 1, the passage cross-sectional area of the refrigerant passage is fixed. Therefore, it is difficult to obtain a high boosting capacity under all operating conditions regardless of the load fluctuation of the refrigerating cycle apparatus by simply changing the passage shape of the mixing portion to a truncated cone shape.

Further, in the ejector applied to the ejector type refrigeration cycle, even if the same means as the steam ejector of Patent Document 2 is adopted, it is not always possible to enhance the pressure recovery action of the shock wave and increase the boosting amount of the refrigerant.

The reason is that the steam ejector injects the gas-phase fluid from the drive-side nozzle, and the ejector applied to the refrigeration cycle device generally injects the gas-liquid two-phase refrigerant from the drive-side nozzle. be. This is because the mode of generating a shock wave in the steam ejector that injects the gas-phase fluid from the drive-side nozzle portion and the mode of generating the shock wave in the ejector that injects the gas-liquid two-phase fluid from the drive-side nozzle portion are different.

In view of the above points, it is an object of the present disclosure to provide an ejector capable of exhibiting a high boosting ability by using a shock wave regardless of the load fluctuation of the applied refrigeration cycle device.

In order to achieve the above object, the ejector of the first aspect of the present disclosure is an ejector applied to a refrigeration cycle apparatus, and includes a drive side nozzle portion and a body portion.

The drive-side nozzle section decompresses the drive-side refrigerant and accelerates it until it reaches supersonic speed, and injects the drive-side injection refrigerant in a gas-liquid two-phase state.

The body section has a refrigerant suction port, a suction side nozzle section, a mixing section, and a diffuser section. The refrigerant suction port sucks the suction side refrigerant. The suction side nozzle portion decompresses and injects the suction side refrigerant sucked from the refrigerant suction port. The mixing unit mixes the suction-side injection refrigerant injected from the suction-side nozzle unit and the drive-side injection refrigerant injected from the drive-side nozzle unit. The diffuser section converts the kinetic energy of the mixed refrigerant mixed in the mixing section into pressure energy.

The drive side injection port of the drive side nozzle portion and the suction side injection port of the suction side nozzle portion are opened so that the injection direction of the drive side injection refrigerant and the injection direction of the suction side injection refrigerant are in the same direction.

Further, the pressure of the drive side injection refrigerant is higher than the pressure of the suction side injection refrigerant, and the mixed refrigerant flowing out of the mixing section and flowing into the diffuser section is the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side. It is an ejector that has a subsonic speed as well as matching.

According to this, the refrigerant pressure of the drive-side injection refrigerant decompressed by the drive-side nozzle portion is higher than the refrigerant pressure of the suction-side injection refrigerant decompressed by the suction-side nozzle portion. Therefore, regardless of the load fluctuation of the refrigeration cycle device, the drive-side refrigerant can be insufficiently expanded in the drive-side nozzle portion, and a shock wave can be reliably generated in the mixing portion. As a result, the mixed refrigerant can be boosted by the pressure recovery action of the shock wave in the mixing section.

Furthermore, the flow velocity of the mixed refrigerant flowing out of the mixing section and flowing into the diffuser section is subsonic. Therefore, even if a pseudo-shock wave that may cause energy loss is generated in the mixing portion by the first shock wave generated by the drive-side injection refrigerant, the pseudo-shock wave can be quickly extinguished.

In addition to this, in the mixing section, the drive side injection refrigerant and the suction side injection refrigerant so that the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side of the mixed refrigerant flowing out of the mixing section and flowing into the diffuser section match. And are mixed. Therefore, even if the generation range of the pseudo-shock wave changes due to the load fluctuation of the refrigeration cycle device, the pseudo-shock wave can be surely extinguished in the mixing unit.

As a result, it is possible to provide an ejector capable of exerting a high boosting ability by utilizing a shock wave regardless of the load fluctuation of the applied refrigeration cycle device.

Here, the pseudo-shock wave refers to the refrigerant pressure on the central axis side in the refrigerant passage due to the generation of an expansion wave on the downstream side of the first shock wave generated by the drive-side injection refrigerant, as described in the embodiment described later. This is a phenomenon in which the refrigerant pressure on the wall surface side becomes a different value and a shock wave is generated again.

It is a schematic whole block diagram of the ejector type refrigeration cycle of 1st Embodiment. It is sectional drawing in the axial direction of the ejector of 1st Embodiment. It is explanatory drawing for demonstrating a pseudo shock wave. It is a graph which shows the relationship between the initial Mach number and the mixing part distance necessary for extinguishing a pseudo shock wave. It is a graph which shows the pressure change on the inner wall surface side of an ejector with respect to the change of the refrigerant pressure at the outlet of a diffuser part. It is explanatory drawing which schematically showed the generation mode of the pseudo-shock wave of an ejector under the operation condition OP1. It is explanatory drawing which schematically showed the generation mode of the pseudo-shock wave of an ejector under the operation condition OP2. It is explanatory drawing which schematically showed the generation mode of the pseudo-shock wave of an ejector under the operation condition OP3. It is explanatory drawing which schematically showed the generation mode of the pseudo-shock wave of an ejector under the operation condition OP4. It is explanatory drawing for demonstrating the generation mode of the expansion wave in the drive nozzle part of the ejector of 1st Embodiment. It is sectional drawing in the axial direction of the ejector of 2nd Embodiment. It is a schematic whole block diagram of the ejector type refrigeration cycle of 3rd Embodiment.

Hereinafter, a plurality of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be given to the parts corresponding to the matters described in the preceding embodiments, and duplicate explanations may be omitted. When only a part of the configuration is described in each embodiment, other embodiments described above can be applied to the other parts of the configuration. Not only the combination of the parts that clearly indicate that the combination is possible in each embodiment, but also the partial combination of the embodiments even if the combination is not specified if there is no problem in the combination. Is also possible.

(First Embodiment)
The first embodiment of the present disclosure will be described with reference to FIGS. 1 to 10. As shown in FIG. 1, the ejector 13 of the present embodiment is applied to the ejector type refrigeration cycle 10. The ejector type refrigeration cycle 10 is a steam compression type refrigeration cycle apparatus including an ejector. The ejector type refrigeration cycle 10 is applied to an air conditioner for a vehicle, and cools the blown air blown into the vehicle interior, which is a space to be air-conditioned.

In the ejector type refrigeration cycle 10, an HFO-based refrigerant (specifically, R1234yf) is used as the refrigerant. The ejector type refrigeration cycle 10 constitutes a subcritical refrigeration cycle in which the refrigerant pressure on the high pressure side does not exceed the critical pressure of the refrigerant. Refrigerant oil for lubricating the compressor 11 of the ejector type refrigeration cycle 10 is mixed in the refrigerant. A part of the refrigerating machine oil circulates in the ejector type refrigerating cycle 10 together with the refrigerant.

The compressor 11 sucks in the refrigerant, compresses it, and discharges it in the ejector type refrigeration cycle 10. The compressor 11 is an electric compressor that rotationally drives a fixed-capacity compression mechanism having a fixed discharge capacity by an electric motor. The number of revolutions (that is, the refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from the control device 20 described later.

The refrigerant inlet side of the radiator 12 is connected to the discharge port of the compressor 11. The radiator 12 is a heat exchanger for heat dissipation that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the outside air (that is, outside air) blown by the cooling fan 12a to dissipate the high-pressure refrigerant and condense it. Is. The cooling fan 12a is an electric fan whose rotation speed (that is, blowing capacity) is controlled by a control voltage output from the control device 20.

The drive side inlet 31a side of the drive side nozzle portion 31 of the ejector 13 is connected to the refrigerant outlet of the radiator 12. The ejector 13 is a refrigerant decompression unit that depressurizes the drive-side refrigerant flowing out of the radiator 12. The ejector 13 is also a refrigerant transport unit that sucks and transports the refrigerant flowing out of the evaporator 16 described later. Further, the ejector 13 is also a refrigerant boosting unit that boosts the pressure of the refrigerant flowing into the inside.

The detailed configuration of the ejector 13 will be described with reference to FIG. 2 and the like. The ejector 13 has a drive-side nozzle portion 31 and a body portion 32.

The drive-side nozzle unit 31 injects the drive-side injection refrigerant in a gas-liquid two-phase state in which the drive-side refrigerant is issentropically decompressed and accelerated to a supersonic speed into the mixing unit 323 of the body unit 32. .. A drive-side inlet 31a is formed on the most upstream side of the refrigerant flow of the drive-side nozzle portion to allow the drive-side refrigerant, which is a high-pressure refrigerant flowing out of the radiator 12, to flow in. A drive-side injection port 31e for injecting the drive-side injection refrigerant is formed in the most downstream portion of the refrigerant flow of the drive-side nozzle portion 31.

The drive side nozzle portion 31 has a tip detail 31b, a throat portion 31c, and a divergent portion 31d. The detail 31b is a portion where the passage cross-sectional area of the refrigerant flowing in from the drive side inlet 31a is reduced as the refrigerant flows toward the downstream side. The throat portion 31c is a portion that most reduces the passage cross-sectional area of the refrigerant. The suehiro portion 31d is a portion that expands the passage cross-sectional area of the refrigerant as it goes from the throat portion 31c to the drive side injection port 31e. That is, in the ejector 13, a so-called Laval nozzle is adopted as the drive side nozzle portion 31.

The drive-side nozzle portion 31 is formed by subjecting a metal (in this embodiment, stainless steel) cylindrical member to plastic working. The thickness of the portion forming the tip detail 31b and the divergent portion 31d of the drive-side nozzle portion 31 is substantially constant. Therefore, the appearance shapes of the tip detail 31b and the divergent portion 31d are changed in the same manner as the shape of the refrigerant passage formed inside. Of course, the drive-side nozzle portion 31 may be formed by cutting a block-shaped metal member.

The shape of the refrigerant passage of the drive-side nozzle portion 31 is determined so that the flow velocity of the drive-side injection refrigerant injected from the drive-side injection port 31e is equal to or higher than the sound velocity of the gas-liquid two-phase refrigerant. .. Further, the speed of the gas phase refrigerant in the refrigerant passage of the drive side nozzle portion 31 is determined to be equal to or lower than the gas phase sound velocity which is the sound velocity of the gas phase refrigerant.

Specifically, regarding the shape of the refrigerant passage of the drive-side nozzle portion 31, the relationship between the throat area Anzth and the drive-side injection port area Anzout is determined so as to satisfy the following mathematical formula F1.
1.3 ≤ Anzout / Anzth ≤ 1.5 ... (F1)
Here, the throat area Anzth is the passage cross-sectional area of the throat 31c. The drive-side injection port area Anzout is the passage cross-sectional area of the drive-side injection port 31e.

Next, the body portion 32 is formed of a tubular member made of metal (made of aluminum in this embodiment). The body portion 32 forms the outer shell of the ejector 13. The drive-side nozzle portion 31 is fixed to the inside of the body portion 32 on one end side in the longitudinal direction by press fitting. The central axis of the drive-side nozzle portion 31 and the central axis of the body portion 32 are arranged coaxially. The body portion 32 may be formed of a resin tubular member.

The body portion 32 has a refrigerant suction port 321, a suction side nozzle portion 322, a mixing portion 323, and a diffuser portion 324.

The refrigerant suction port 321 is formed on the cylindrical side surface of the body portion 32. The refrigerant suction port 321 is a through hole for sucking the suction-side refrigerant flowing out of the evaporator 16 into the ejector 13 by the suction action of the drive-side injection refrigerant jetted from the drive-side nozzle portion 31.

The refrigerant suction port 321 communicates with the suction space 321a formed inside the body portion 32. The suction space 321a is formed by coaxially arranging the tip details 31b and the divergent portion 31d of the drive-side nozzle portion 31 in the columnar space formed inside the body portion 32. Therefore, the suction space 321a is formed in an annular cross section on the outer peripheral side of the tip detail 31b and the divergent portion 31d of the drive side nozzle portion 31.

The suction side nozzle unit 322 decompresses the suction side refrigerant sucked into the suction space 321a through the refrigerant suction port 321 and injects it into the mixing unit 323. The suction-side nozzle portion 322 is a downstream portion of the suction space 321a in the body portion 32, and is formed on the outer peripheral side of the tip end portion of the divergent portion 31d of the drive-side nozzle portion 31. Therefore, the refrigerant passage of the suction side nozzle portion 322 is formed in an annular cross section between the outer peripheral surface of the divergent portion 31d and the inner peripheral surface of the body portion 32.

As described above, the outer peripheral portion of the divergent portion 31d of the drive-side nozzle portion 31 is formed in a shape that increases the outer diameter toward the downstream side of the refrigerant flow, similar to the shape of the internal refrigerant passage. Therefore, the annular refrigerant passage of the suction side nozzle portion 322 has a shape in which the cross-sectional area of the passage decreases toward the downstream side of the refrigerant flow. That is, in the ejector 13, a so-called tapered nozzle is substantially adopted as the suction side nozzle portion 322.

The suction side injection port 322a of the suction side nozzle portion 322 is opened in an annular shape around the drive side injection port 31e. The drive side injection port 31e and the suction side injection port 322a are open on the same plane. The outer diameter of the suction side injection port 322a coincides with the mixing portion inlet diameter Dmix, which is the inner diameter of the inlet portion of the mixing portion 323.

Therefore, in the drive side injection port 31e and the suction side injection port 322a, the drive side injection refrigerant immediately after being injected from the drive side injection port 31e and the suction side injection refrigerant immediately after being injected from the suction side injection port 322a are substantially parallel to each other. It is open to flow. In other words, the drive-side injection port 31e and the suction-side injection port 322a are opened so that the injection direction of the drive-side injection refrigerant immediately after injection and the injection direction of the suction-side injection refrigerant immediately after injection are in the same direction. is doing.

The decompression performance of the drive-side nozzle unit 31 and the decompression performance of the suction-side nozzle unit 322 are the suction immediately after the pressure of the drive-side injection refrigerant immediately after being injected from the drive-side injection port 31e is injected from the suction-side injection port 322a. It is determined to be higher than the pressure of the side injection refrigerant.

Specifically, the drive-side injection port area Anzout of the drive-side nozzle unit 31 and the suction-side injection port area Asnout of the suction-side nozzle unit 322 are determined to satisfy the following formula F2.
2 ≦ Asnout / Anzout ≦ 4… (F2)
Here, the suction side injection port area Asnout is the passage cross-sectional area of the suction side injection port 322a.

According to the above formula F2, the drive side injection port area Anzout is smaller than the suction side injection port area Asnout. However, the drive-side refrigerant is a high-pressure refrigerant flowing out of the radiator 12, and the suction-side refrigerant is a low-pressure refrigerant flowing out of the evaporator 16. Therefore, if the suction side injection port area Asnout and the drive side injection port area Anzout are determined so as to satisfy the equation F2, the pressure of the drive side injection refrigerant can be made higher than the pressure of the suction side injection refrigerant. can.

The mixing unit 323 forms a mixing space 323a that mixes the drive-side injection refrigerant and the suction-side injection refrigerant. The mixing unit 323 is arranged on the downstream side of the refrigerant flow of the drive side injection port 31e and the suction side injection port 322a in the body unit 32. The mixed space 323a is formed in a substantially truncated cone shape that expands the cross-sectional area of the passage toward the downstream side of the refrigerant flow.

In the mixing unit 323, the drive side injection refrigerant and the suction side injection refrigerant are mixed so that the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side of the mixed refrigerant flowing out from the mixing unit 323 match. In the mixing unit 323, the drive side injection refrigerant and the suction side injection refrigerant are mixed so that the mixed refrigerant flowing out from the mixing unit 323 does not have a pressure distribution and the pressure is uniform. Further, in the mixing unit 323, the drive side injection refrigerant and the suction side injection refrigerant are mixed so that the flow velocity of the gas-liquid two-phase mixed refrigerant flowing out of the mixing unit 323 and flowing into the diffuser unit 324 becomes subsonic. Let me.

Here, on the downstream side of the refrigerant flow from the mixing portion 323 of the ejector 13, the cross-sectional area of the passage does not decrease as the refrigerant flows toward the downstream side. The passage cross-sectional area does not shrink. Therefore, in the mixing unit 323, the gas-liquid two-phase mixed refrigerant that has become subsonic at a uniform pressure is not accelerated to supersonic speed again on the downstream side of the refrigerant flow from the mixing unit 323.

Therefore, no shock wave is generated on the downstream side of the refrigerant flow than the mixing unit 323. That is, the passage shape of the mixing unit 323 is such that the shock wave generated by the driving-side injection refrigerant injected from the driving-side nozzle unit 31 at supersonic speed is extinguished in the mixing unit 323.

Specifically, for the passage shape of the mixing unit 323, the mixing unit distance L is determined so as to satisfy the following mathematical formula F3. The relaxation distance Lv is defined below by the mathematical formula F4.
Lv <L ... (F3)
Lv = U ₀ × (ρ _L × D _L ² ) / (18 × μ _G )… (F4)
Here, the mixing section distance L is an axial length from the inlet to the exit of the mixing section 323.

Further, U ₀ of the equation F4 is the average mass flow velocity of the mixed refrigerant in the most upstream portion of the first shock wave generated in the mixing portion 323 by the driving side injection refrigerant. ρ _L is the density of the particles (hereinafter referred to as droplets) of the liquid phase refrigerant in the mixed refrigerant in the uppermost stream portion of the first shock wave. _DL is the average diameter of the droplets in the mixed refrigerant at the most upstream part of the first shock wave. μ _G is the viscosity of the gas phase refrigerant in the mixed refrigerant at the most upstream part of the first shock wave.

As shown in Equation F4, the relaxation distance Lv integrates the timeless relaxation time expressed by the ratio of the inertial force and the viscosity of the droplet to _{the average mass flow velocity U 0} of the mixed refrigerant in the most upstream part of the first shock wave. It is a value corresponding to the distance. The relaxation distance Lv represents the distance obtained by integrating the initial speed of the mixed refrigerant in the most upstream portion of the shock wave and the time until the flow velocity of the gas phase refrigerant in the mixed refrigerant and the flow velocity of the droplet become equal.

Therefore, in order to eliminate the first shock wave in the mixing section 323 by the driving side injection refrigerant, at least the mixing section distance L needs to be larger than the relaxation distance Lv. That is, it is necessary to satisfy the above formula F3.

_{By the way, if the initial Mach number M 0,} which is the Mach number of the mixed refrigerant in the most upstream part of the first shock wave, is a relatively high value, an expansion wave may be generated on the downstream side of the first shock wave. .. Then, due to the expansion wave generated on the downstream side of the first shock wave, the refrigerant flow velocity on the central axis side of the mixing unit 323 becomes subsonic, but the refrigerant flow velocity on the turbulent boundary layer side becomes supersonic again. ..

As a result, the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side of the mixing unit 323 change at different values, and a phenomenon called a pseudo-shock wave may occur in which a shock wave is generated again. In a pseudo-shock wave, a plurality of shock waves are generally generated until the fluid on the downstream side of the expansion wave becomes subsonic. The pseudo-shock wave causes an energy loss of the refrigerant flowing inside the ejector due to the entropy generation by the shock wave and the increase in the friction loss of the refrigerant due to the expansion wave.

Pseudo-shock waves are roughly classified into a shock train region (shock train region) and a mixing region (mixing region), as schematically shown in FIG. The shock train region is a region in which the height relationship between the fluid pressure Pmi on the central axis side of the fluid passage and the fluid pressure Pmo on the wall surface side changes periodically. Further, the mixing region is a region in which the fluid pressure Pmi on the central axis side of the mixing portion and the fluid pressure Pmo on the wall surface side are substantially equivalent and change.

Note that FIG. 3 is an explanatory diagram schematically showing the generation mode of the pseudo-shock wave generated in the gas phase fluid flowing in the fluid passage of the circular tube 100 and the fluid pressure on the axial cross-sectional view of the circular tube 100. be. The non-hatched region in the circular tube 100 of FIG. 3 is a region in which a supersonic fluid is mainly distributed. The point hatch region is a region where subsonic fluids are mainly distributed.

The thick line in the circular tube 100 of FIG. 3 indicates a shock wave, and the double broken line indicates an expansion wave. In FIG. 3, three shock waves and three expansion waves are schematically represented, but the number of shock waves and expansion waves is not limited to this. Further, the pseudo-shock wave is not a phenomenon that always occurs, and does not occur when the initial Mach number M ₀ is a relatively low value.

By the way, the pseudo-shock wave is generally recognized as a phenomenon confirmed by the steam ejector. The steam ejector is an ejector in which a vapor phase fluid flows inside and the outlet of the diffuser portion is opened to the atmosphere. The steam ejector is used for a vacuum exhaust device, a smoke exhaust suction device, an aircraft air intake, and the like.

On the other hand, as a result of the test study, the present inventors confirmed that a pseudo-shock wave is generated even in the ejector in which the gas-liquid two-phase fluid flows inside. Furthermore, the present inventors have also confirmed that the mode of generation of the pseudo-shock wave generated by the steam ejector is different from the mode of generation of the pseudo-shock wave generated by the ejector through which the gas-liquid two-phase fluid flows.

In the following explanation, for the sake of clarification, the pseudo-shock wave generated by the steam ejector through which the gas-phase fluid flows is described as the pseudo-shock wave in the gas-phase flow. Further, a pseudo-shock wave generated by an ejector through which a gas-liquid two-phase fluid flows is described as a pseudo-shock wave in a two-phase flow.

The reason why the pseudo-shock wave generation mode in the gas-phase flow and the pseudo-shock wave generation mode in the two-phase flow are different is that droplets are present in the gas-liquid two-phase fluid. Specifically, the vapor phase refrigerant in the shock wave rapidly decreases the flow velocity, but the droplet has an inertial force, so that the velocity decrease becomes slower than that of the vapor phase refrigerant. Further, the gas phase refrigerant in the expansion wave rapidly increases the flow velocity, but the droplets accelerate more slowly than the gas phase refrigerant due to the drag force from the gas phase refrigerant.

Furthermore, it has been found that pseudo-shock waves in two-phase flow are less likely to occur as the dryness of the drive-side injection refrigerant decreases. The reason is that the droplet has the effect of attenuating the pressure wave by scattering or 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 droplets.

Therefore, the present inventors have conducted a study for promptly extinguishing the pseudo-shock wave in the two-phase flow when the pseudo-shock wave in the two-phase flow is generated in the mixing unit 323 in the ejector 13.

As a result, as shown in FIG. 4, it was found that the axial length required to extinguish the pseudo-shock wave in the two-phase flow _{increases as the initial Mach number M 0 increases.} Further, it was found that the axial length required to extinguish the pseudo-shock wave in the two-phase flow increases as the dryness X of the refrigerant flowing through the mixing portion 323 increases. In FIG. 4, the axial length required to extinguish the pseudo shock wave is represented by the ratio to the relaxation distance Lv.

Then, in the ejector applied to the ejector type refrigeration cycle, if the relationship between the mixing section distance L and the relaxation distance Lv is determined so as to satisfy the following mathematical formula F5, the pseudo shock wave can be extinguished in the mixing section. I found it.
1 <L / Lv≤3.5 (however, 1 <M ₀ <2.5) ... (F5)
Further, when the relationship shown in the formula F5 is converted into the flow path shape, if the relationship between the mixing section distance L and the mixing section inlet diameter Dmix is determined so as to satisfy the following formula F6, the pseudo shock wave is extinguished in the mixing section. I found that I could do it.
1 <L / Dmix ≦ 10 (however, 1 <M ₀ <2.5)… (F6)
Here, the mixing portion inlet diameter Dmix is the diameter of the refrigerant passage at the inlet of the mixing portion 323.

The mixing portion inlet diameter Dmix coincides with the outer diameter of the suction side injection port 322a of the suction side nozzle portion 322. Further, the range of the initial Mach number M ₀ in the formulas F5 and F6 is a range that can be practically used in an ejector applied to a general ejector type refrigeration cycle.

The mixing section distance L of the mixing section 323 of the ejector 13 is determined to satisfy the above equations F3, F5, and F6. Therefore, in the mixing unit 323, not only the pressure of the mixed refrigerant is increased, but also the flow velocity of the mixed refrigerant is greatly reduced. As a result, the refrigerant on the wall surface side of the mixing unit 323 is likely to be separated from the wall surface. The peeling of the refrigerant on the wall surface side of the mixing unit 323 from the wall surface hinders the flow of the mixed refrigerant and causes energy loss.

Therefore, the passage shape of the mixing portion 323 is formed so that the cross-sectional area of the passage increases as the mixed refrigerant moves toward the downstream side in the flow direction. Specifically, the area change rate dA / dz is determined so that the passage shape of the mixing unit 323 satisfies the following mathematical formulas F7 within the range satisfying the above mathematical formulas F5 and F6.
0 <dA / dz≤0.8 (mm) ... (F7)
^{Here, the area change rate dA / dz is the amount of change dA (mm 2} ) in the cross-sectional area of the refrigerant passage per unit length dz (mm) in the axial direction in the mixing unit 323. Further, in the mixing unit 323, the area change rate dA / dz is increased toward the downstream side of the refrigerant flow.

The diffuser unit 324 forms a step-up passage 324a that converts the kinetic energy of the mixed refrigerant mixed in the mixing unit 323 into pressure energy. The inlet of the boost passage 324a is formed so as to be continuous with the outlet of the mixing portion 323. The booster passage 324a is formed in a substantially truncated cone shape in which the cross-sectional area of the passage is expanded toward the downstream side of the refrigerant flow. Due to this shape, the diffuser unit 324 decelerates the mixed refrigerant and boosts the pressure of the mixed refrigerant.

Further, the passage shape of the boost passage 324a is determined so that the flow velocity of the mixed refrigerant flowing out of the mixing section 323 and flowing into the diffuser section 324 is subsonic.

Specifically, in the passage shape of the diffuser portion 324, the relationship between the mixing portion outlet area Amixout and the diffuser portion outlet area Aout is determined so as to satisfy the following mathematical formula F8.
0.3 ≤ Amixout / Aout ≤ 0.6 ... (F8)
Here, the mixing section outlet area Amixout is the passage cross-sectional area of the exit of the mixing section 323. The mixed-section outlet area Amixout coincides with the passage cross-sectional area of the inlet of the diffuser section 324. Further, the diffuser section outlet area Aout is the passage cross-sectional area of the outlet of the diffuser section 324.

In the ejector applied to the ejector type refrigeration cycle, the refrigerant flowing out from the diffuser section has a certain flow velocity in order to reduce the power consumption of the compressor. In a general ejector type refrigeration cycle, the flow velocity of the refrigerant flowing out from the diffuser portion may be a subsonic speed of about 0.1 to 0.2 times the speed of sound.

Therefore, if the passage cross-sectional area of the diffuser section 324 is expanded so as to satisfy the above formula F8, the flow velocity of the mixed refrigerant flowing out of the mixing section 323 and flowing into the diffuser section 324 does not exceed the speed of sound. ..

As shown in FIG. 1, the inlet side of the accumulator 14 is connected to the outlet of the diffuser portion 324. The accumulator 14 is a gas-liquid separation unit that separates the gas-liquid of the refrigerant flowing out of the diffuser unit 324. Further, the accumulator 14 is a liquid storage unit that stores a part of the separated liquid phase refrigerant as a surplus refrigerant in the cycle.

The suction port side of the compressor 11 is connected to the gas phase refrigerant outlet of the accumulator 14. On the other hand, the refrigerant inlet side of the evaporator 16 is connected to the liquid phase refrigerant outlet of the accumulator 14 via a fixed throttle 15 as a depressurizing means. As the fixed throttle 15, an orifice, a capillary tube, or the like can be adopted.

The evaporator 16 is for heat absorption to cool the blown air by evaporating the low pressure refrigerant by exchanging heat between the low pressure refrigerant decompressed by the fixed throttle 15 and the blown air blown from the indoor blower 16a toward the vehicle interior. It is a heat exchanger. The indoor blower 16a is an electric blower whose rotation speed (that is, blower capacity) is controlled by a control voltage output from the control device 20. The refrigerant outlet of the evaporator 16 is connected to the refrigerant suction port 321 side of the ejector 13.

Next, the electric control unit of the ejector type refrigeration cycle 10 will be described. The control device 20 includes a well-known microcomputer including a CPU, ROM, RAM, and the like, and peripheral circuits thereof. The control device 20 performs various calculations and processes based on the air conditioning control program stored in the ROM, and controls the operation of various controlled target devices 11, 12a, 16a, etc. connected to the output side.

Further, a plurality of sensors for air conditioning control such as an inside air temperature sensor, an outside air temperature sensor, a solar radiation sensor, an evaporator temperature sensor, and a discharge pressure sensor are connected to the input side of the control device 20. The detection values of these sensor groups are input to the control device 20.

More specifically, the internal air temperature sensor is an internal air temperature detection unit that detects the temperature inside the vehicle. The outside air temperature sensor is an outside air temperature detection unit that detects the outside air temperature. The solar radiation sensor is a solar radiation amount detection unit that detects the amount of solar radiation in the vehicle interior. The evaporator temperature sensor is an evaporator temperature detection unit that detects the temperature of the blown air (evaporator temperature) of the evaporator 16. The discharge pressure sensor is a discharge refrigerant pressure detection unit that detects the pressure of the refrigerant discharged from the compressor 11.

Further, an operation panel (not shown) arranged near the instrument panel in the front part of the vehicle interior is connected to the input side of the control device 20. In the control device 20, operation signals from various operation switches provided on the operation panel are input to the control device. As various operation switches provided on the operation panel, an air conditioning operation switch that requires air conditioning in the vehicle interior, a vehicle interior temperature setting switch that sets the vehicle interior temperature, and the like are provided.

The control device 20 is integrally configured with a control unit that controls the operation of various controlled devices connected to the output side. Among the control devices 20, a configuration (that is, hardware and software) that controls the operation of each control target device constitutes a control unit of each control target device. For example, a configuration that controls the operation of the compressor 11 constitutes a discharge capacity control unit.

Further, in FIG. 1 and the like, a power line or a signal line connecting the control device 20 and various controlled devices is shown, but for the sake of clarification of the illustration, the sensor group and the control device 20 and the sensor group are shown. The illustration of the signal line to be connected is omitted.

Next, the operation of the ejector type refrigeration cycle 10 of the present embodiment in the above configuration will be described. When the air conditioning operation switch on the operation panel is turned on (ON), the control device 20 operates the compressor 11, the cooling fan 12a, the indoor blower 16a, and the like. As a result, the compressor 11 sucks in the refrigerant, compresses it, and discharges it.

The high-temperature and high-pressure refrigerant discharged from the compressor 11 flows into the radiator 12. The high-pressure refrigerant flowing into the radiator 12 exchanges heat with the outside air blown from the cooling fan 12a and condenses. The refrigerant condensed by the radiator 12 flows into the drive-side inlet 31a of the drive-side nozzle portion 31 of the ejector 13 as the drive-side refrigerant. In the drive-side nozzle unit 31, the drive-side refrigerant is issentropically depressurized.

The drive-side refrigerant that has flowed into the drive-side nozzle portion 31 reaches a critical state at the throat portion 31c, and the drive flow rate of the ejector 13 is determined. The drive-side refrigerant is accelerated at the divergent portion 31d until it reaches a supersonic state. Then, it becomes a drive-side injection refrigerant in a gas-liquid two-phase state and is injected from the drive-side injection port 31e into the mixing space 323a of the mixing unit 323. The drive-side injection refrigerant is a supersonic mist flow that exceeds the two-phase sound velocity.

Further, the refrigerant flowing out of the evaporator 16 is sucked from the refrigerant suction port 321 into the suction space 321a as the suction side refrigerant by the suction action of the drive side injection refrigerant injected from the drive side injection port 31e to the mixing unit 323. More specifically, since the drive-side injection refrigerant is in a gas-liquid two-phase state, the injected droplets accelerate due to the action of inertial force, thereby reducing the pressure in the vicinity of the suction-side injection port 322a. As a result, the suction side refrigerant is sucked into the suction space 321a.

The suction-side refrigerant sucked into the suction space 321a is depressurized by the suction-side nozzle portion 322, becomes a suction-side injection refrigerant, and is injected from the suction-side injection port 322a into the mixing space 323a of the mixing section 323. The refrigerant pressure of the drive-side injection refrigerant injected to the mixing unit 323 is higher than the refrigerant pressure of the suction-side injection refrigerant injected to the mixing unit 323. Therefore, in the drive-side nozzle unit 31, the drive-side refrigerant is insufficiently expanded to generate an expansion wave in the mixing unit 323.

The expansion wave generated by the drive-side injection refrigerant is reflected on the wall surface of the mixing section 323 and the turbulent boundary layer to generate a shock wave in the mixing section 323. In the mixing unit 323, the pressure of the mixed refrigerant of the driving side injection refrigerant and the suction side injection refrigerant increases due to the pressure recovery action of the shock wave generated by the drive side injection refrigerant. Further, in the mixing unit 323, the drive side injection refrigerant and the suction side injection refrigerant are mixed so as to be a gas-liquid two-phase mixed refrigerant having a subsonic speed at a uniform pressure.

The mixed refrigerant flowing out of the mixing section 323 flows into the diffuser section 324. In the diffuser section 324, the kinetic energy of the mixed refrigerant is converted into pressure energy by expanding the cross-sectional area of the passage. As a result, the pressure of the mixed refrigerant further increases.

The refrigerant flowing out of the diffuser unit 324 flows into the accumulator 14 and is gas-liquid separated. The liquid phase refrigerant separated by the accumulator 14 is depressurized by the fixed throttle 15 and flows into the evaporator 16. The refrigerant flowing into the evaporator 16 absorbs heat from the blown air blown by the indoor blower 16a and evaporates. As a result, the blown air is cooled.

As described above, the refrigerant flowing out of the evaporator 16 becomes a suction side refrigerant and is sucked from the refrigerant suction port 321 of the ejector 13. On the other hand, the gas phase refrigerant separated by the accumulator 14 is sucked into the compressor 11 and compressed again.

The ejector type refrigeration cycle 10 operates as described above and can cool the blown air blown into the vehicle interior.

In the ejector type refrigeration cycle 10, the refrigerant boosted by the ejector 13 is sucked into the compressor 11. As a result, in the ejector type refrigeration cycle 10, the pressure of the suction refrigerant sucked into the compressor 11 is higher than that of the normal refrigeration cycle device in which the refrigerant evaporation pressure in the evaporator and the pressure of the suction refrigerant of the compressor are substantially equal to each other. Can be made to. Therefore, in the ejector type refrigeration cycle 10, the consumption power of the compressor 11 can be reduced and the coefficient of performance (COP) of the cycle can be improved as compared with the normal refrigeration cycle apparatus.

Further, since the ejector type refrigeration cycle 10 of the present embodiment is provided with the ejector 13, high COP can be exhibited regardless of the load fluctuation. That is, the ejector 13 of the present embodiment can exhibit a high boosting ability regardless of the load fluctuation.

More specifically, in the ejector 13, the refrigerant pressure of the drive-side injection refrigerant injected to the mixing unit 323 is higher than the refrigerant pressure of the suction-side injection refrigerant. Therefore, regardless of the load fluctuation of the ejector type refrigeration cycle 10, the drive-side refrigerant can be insufficiently expanded by the drive-side nozzle unit 31 to surely generate a shock wave in the mixing unit 323. As a result, the mixing refrigerant can be boosted by the pressure recovery action of the shock wave in the mixing unit 323.

Further, in the ejector 13, the flow velocity of the mixed refrigerant flowing out from the mixing section 323, flowing out, and flowing into the diffuser section 324 is reduced to subsonic speed. As a result, the shock wave generated by the drive-side injection refrigerant can be reliably eliminated in the mixing unit 323. Therefore, it is possible to suppress the energy loss caused by the shock wave after exerting the pressure recovery action.

In other words, even if a pseudo-shock wave in a two-phase flow is generated in the mixing unit 323 due to the load fluctuation of the ejector type refrigeration cycle 10, the pseudo-shock wave is quickly extinguished and the energy loss due to the entropy generation of the pseudo-shock wave is reduced. It can be suppressed.

In addition to this, in the mixing section 323, the driving side injection refrigerant so as to match the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side of the mixed refrigerant flowing out from the mixing section 323 and flowing out into the diffuser section 324. And the suction side injection refrigerant are mixed. Therefore, even if the generation range of the pseudo-shock wave in the two-phase flow changes due to the load fluctuation of the refrigeration cycle device, the pseudo-shock wave can be surely extinguished in the mixing unit 323.

As a result, according to the ejector 13 of the present embodiment, it is possible to exert a high boosting ability by utilizing a shock wave regardless of the load fluctuation of the applied refrigerating cycle apparatus. Further, in the ejector 13 in which the gas-liquid two-phase refrigerant flows inside, the pressure wave can be attenuated by the droplets contained in the gas-liquid two-phase refrigerant. Therefore, it is possible to suppress the generation of noise and vibration even if the shock wave is used to exert a high boosting ability.

Furthermore, the present inventors are also studying to effectively boost the pressure of the mixed refrigerant by the pressure recovery action of the shock wave in the ejector 13. FIG. 5 is a graph showing the examination results.

In FIG. 5, when the inlet pressure Pin of the drive-side refrigerant flowing into the ejector 13, the dryness X of the drive-side refrigerant, and the suction flow rate of the suction-side refrigerant are constant, and the refrigerant pressure at the outlet of the diffuser unit 324 is changed. It shows the pressure change inside the ejector 13. More specifically, FIG. 5 shows the static pressure distribution in the vicinity of the inner wall surface of the ejector 13 for the following four operating conditions OP1 to OP4.

The operating condition OP1 is the operating condition in which the refrigerant pressure at the outlet of the diffuser unit 324 is minimized. The operating condition OP2 is an operating condition in which the refrigerant pressure at the outlet of the diffuser unit 324 is higher than that of the operating condition OP1. The operating condition OP3 is an operating condition in which the refrigerant pressure at the outlet of the diffuser unit 324 is higher than that of the operating condition OP2. The operating condition OP4 is an operating condition in which the refrigerant pressure at the outlet of the diffuser unit 324 is higher than that of the operating condition OP3.

Therefore, the refrigerant pressure at the outlet of the diffuser unit 324 increases in the order of operating condition OP1, operating condition OP2, operating condition OP3, and operating condition OP4. Further, in the graph of FIG. 5, the value obtained by subtracting the refrigerant pressure at the inlet of the mixing unit 323 from the refrigerant pressure at the outlet of the diffuser unit 324 is the boosted amount of the refrigerant as the entire ejector 13. In FIG. 5, for the sake of clarification of the illustration, the boost amount ΔP is shown only for the operating condition OP3.

First, under the operating condition OP1, as shown by the thick broken line in the graph of FIG. 5, the pressure of the mixed refrigerant drops on the inlet side of the diffuser portion 324. Therefore, under the operating condition OP1, as shown in FIG. 6, the supersonic mixed refrigerant enters the diffuser section 324, and the pressure of the supersonic refrigerant drops due to the expansion of the passage cross-sectional area of the diffuser section 324. Is understood.

Further, under the operating condition OP1, the boosting amount of the ejector 13 as a whole is smaller than that of other operating conditions. Therefore, it is understood that a pseudo-shock wave in the two-phase flow is generated, the shock train region extends to the inside of the diffuser portion 324, and the energy loss is increased.

Note that FIG. 6 is an explanatory diagram schematically showing the generation mode of the shock wave generated in the refrigerant flowing in the ejector 13 on the axial cross-sectional view of the ejector 13 in the same manner as in FIG. Therefore, the non-hatched region in the ejector 13 of FIG. 6 is a region in which a supersonic fluid is mainly distributed. The point hatch region is a region where subsonic fluids are mainly distributed. The thick line in the ejector 13 indicates a shock wave, and the double broken line indicates an expansion wave. This also applies to FIGS. 7 to 9.

Next, in the operating condition OP2, as shown by the alternate long and short dash line in the graph of FIG. 5, a steep pressure increase of the mixed refrigerant has started on the downstream side of the mixing unit 323. Therefore, it is understood that in the operating condition OP2, the shock train region is shorter than that in the operating condition OP1, and the pressure recovery action by the shock wave is started on the downstream side of the mixing unit 323.

Further, in the operating condition OP2, the boosting amount of the ejector 13 as a whole is increased as compared with the operating condition OP1. Therefore, in the operating condition OP2, as shown in FIG. 7, the shock wave is extinguished in the mixing unit 323, and the relaxation distance Lv of the pseudo shock wave is reduced as compared with the operating condition OP1 to reduce the energy loss. Is understood.

Next, in the operating condition OP3, as shown by the thick solid line in the graph of FIG. 5, a steep pressure increase of the mixed refrigerant has started near the inlet of the mixing unit 323. That is, the position where the steep pressure rise starts moves to the upstream side of the refrigerant flow from the operating condition OP2. Therefore, it is understood that in the operating condition OP3, the shock train region is shorter than that in the operating condition OP2, and the pressure recovery action by the shock wave starts in the vicinity of the inlet of the mixing unit 323.

Further, in the operating condition OP3, the boosting amount of the ejector 13 as a whole is increased as compared with other operating conditions. Therefore, in the operating condition OP3, as shown in FIG. 8, the shock wave is rapidly extinguished in the mixing unit 323, and the relaxation distance Lv of the pseudo shock wave is reduced as compared with the other operating conditions, thereby further reducing the energy loss. It is understood that it is decreasing.

Next, in the operating condition OP4, as shown in the two-dot chain diagram of FIG. 5, the refrigerant pressure at the inlet of the mixing unit 323 is higher than in the other operating conditions. That is, as shown by the broken line in FIG. 5, the pressure of the drive-side injection refrigerant is increasing. The dashed line in FIG. 5 shows the static pressure distribution in the drive-side nozzle portion 31.

Further, the pressure of the mixed refrigerant starts to rise sharply immediately after flowing into the mixing unit 323. Therefore, under the operating condition OP4, as shown in FIG. 9, it is understood that the drive-side refrigerant cannot be insufficiently expanded in the drive-side nozzle portion 31, and a shock wave is generated inside the drive-side nozzle portion 31. Will be done.

Therefore, in the operating condition OP4, the pressure recovery action of the shock wave cannot be sufficiently utilized to boost the pressure of the mixed refrigerant in the mixing unit 323, and the boosting amount of the ejector 13 as a whole is larger than that of other operating conditions. It has decreased. When the refrigerant pressure at the inlet of the mixing unit 323 rises as in the operating condition OP4, the pressure of the suction side refrigerant also rises, and the refrigerant evaporation temperature in the evaporator 16 may rise.

From the above, in order to effectively boost the pressure of the mixed refrigerant by the pressure recovery action of the shock wave in the mixing unit 323, it is effective to surely insufficiently expand the driving side refrigerant in the driving side nozzle unit 31. understood. Further, it has been found that it is effective to generate the first shock wave generated by the drive-side injection refrigerant in the vicinity of the inlet of the mixing unit 323. Further, it was found that it is effective to quickly extinguish the shock wave generated in the mixing unit 323. That is, it was found that shortening the shock train area is effective.

Therefore, in the ejector 13 of the present embodiment, Asnout / Anzout is set so that the pressure of the drive-side injection refrigerant is higher than the pressure of the suction-side injection refrigerant, as described in the mathematical formula F2.

According to this, the pressure of the drive side injection refrigerant can be made higher than the pressure of the suction side injection refrigerant without requiring complicated operation control or the like according to the load fluctuation. Then, the drive-side nozzle portion 31 can surely inadequately expand the drive-side refrigerant, and can surely generate an expansion wave in the drive-side injection refrigerant.

Further, in the ejector 13 of the present embodiment, as described by the mathematical formula F1, the flow velocity of the drive-side injection refrigerant injected from the drive-side injection port 31e becomes equal to or higher than the two-phase sound velocity, which is the sound velocity of the gas-liquid two-phase refrigerant. And, Anzout / Anzth is set so that the speed of the gas phase refrigerant in the refrigerant passage of the drive side nozzle portion 31 is equal to or lower than the gas phase sound velocity which is the sound velocity of the gas phase refrigerant.

According to this, the drive-side injection refrigerant in the gas-liquid two-phase state can be surely set to the two-phase sound velocity or higher without requiring complicated operation control or the like according to the load fluctuation. Further, the speed of the gas phase refrigerant in the refrigerant passage of the drive side nozzle portion 31 can be set to be equal to or lower than the gas phase sound velocity.

Then, by setting the speed of the gas phase refrigerant in the refrigerant passage of the drive side nozzle portion 31 to be equal to or lower than the gas phase sound velocity, an expansion wave can be generated from the inside of the drive side nozzle portion 31 as shown in FIG. .. This is because the accelerated flow due to the expansion wave draws the gas phase refrigerant having a gas phase sound velocity or less on the outer peripheral side into the drive side nozzle portion 31. As a result, the first shock wave generated in the mixing unit 323 by the drive-side injection refrigerant can be brought close to the vicinity of the inlet of the mixing unit 323.

According to the test study by the present inventor, during normal operation of the ejector type refrigeration cycle 10, the distance L1 from the inlet of the mixing section 323 to the generation of the first shock wave is 0.1 times or less of the mixing section inlet diameter Dmix. It has been confirmed that it will be. Therefore, as described in the operating condition OP3 of FIG. 5, the boosting amount of the ejector 13 as a whole can be increased.

In addition to this, the wall friction in the refrigerant passage of the drive-side nozzle portion 31 can be alleviated, so that the initial Mach number M ₀ can be increased. Therefore, the boost amount of the mixed refrigerant can be further increased by the shock wave having high energy.

Further, in the ejector 13 of the present embodiment, as described by the mathematical formula F3, the mixing portion distance L is set to be longer than the relaxation distance Lv. According to this, the first shock wave generated in the mixing section 323 by the driving side injection refrigerant can be surely extinguished in the mixing section 323. Therefore, the flow velocity of the mixed refrigerant in the gas-liquid two-phase state flowing out of the mixing section 323 and flowing into the diffuser section 324 can be easily brought close to the subsonic speed.

Further, in the ejector 13 of the present embodiment, the range of L / Lv or L / Dmix is set as shown in the formulas F5 and F6. According to this, even if a pseudo-shock wave in the two-phase flow is generated due to the load fluctuation of the ejector type refrigeration cycle 10, the pseudo-shock wave in the two-phase flow can be surely extinguished in the mixing unit 323.

Here, in order to eliminate the pseudo-shock wave in the two-phase flow in the mixing section 323, it is conceivable to simply set the mixing section distance L long. However, if the mixing portion distance L is set long, the physique of the ejector 13 as a whole also becomes large. On the other hand, the mathematical formulas F5 and F6 are extremely effective in that the upper limit value of the mixing unit distance L is shown within the range feasible in actual use.

Further, in the ejector 13 of the present embodiment, as described by the mathematical formula F7, the passage shape of the mixing portion 323 has a shape in which the passage cross-sectional area increases as the mixed refrigerant moves toward the downstream side in the flow direction. There is. According to this, it is possible to suppress the separation of the refrigerant on the wall surface side of the mixing unit 323 from the wall surface and suppress the energy loss.

In the ejector 13 capable of rapidly increasing the pressure of the mixed refrigerant by the pressure recovery action of the shock wave in the mixing unit 323 as in the present embodiment, the flow velocity of the mixed refrigerant suddenly decreases in the mixing unit 323. Therefore, being able to suppress the separation of the refrigerant on the wall surface side of the mixing unit 323 from the wall surface is effective in suppressing energy loss.

Further, in the ejector type refrigerating cycle 10 that employs an HFO-based refrigerant, an HFC-based refrigerant, and a mixed refrigerant in which a plurality of types of these refrigerants are mixed as the refrigerant, the present inventors make a shock wave in the ejector 13 under the following conditions. It has been confirmed that it exerts a high boosting ability by using.

Specifically, it has been confirmed that the ejector 13 exhibits a boosting capacity four times or more that of the conventional technique, at least within the range in which the inlet pressure Pin and the outlet pressure Pout of the ejector 13 satisfy both of the following formulas F9 and F10. is doing.
0.4 ≤ Pin ≤ 1.7 (MPa) ... (F9)
0.3 ≤ Pout ≤ 0.65 (MPa) ... (F10)
Here, the inlet pressure Pin is the pressure of the drive-side refrigerant flowing into the drive-side nozzle portion 31 of the ejector 13. The outlet pressure Pout is the pressure of the refrigerant flowing out from the diffuser unit 324.

Further, it has been confirmed that the ejector 13 exhibits a boosting capacity four times or more that of the conventional technique, at least in the range where the inlet pressure Pin and the drive side injection pressure Pnzout of the ejector 13 are in the following mathematical formula F11.
0.2 ≤ Pnzout / Pin ≤ 0.65 ... (F11)
Here, the drive-side injection pressure Pnzout is the pressure of the drive-side injection refrigerant immediately after being injected from the drive-side injection port 31e.

Further, the HFO-based refrigerant includes R1234zd and the like in addition to R1234yf. The HFC-based refrigerant includes R134a, R410A, R32, R404A, R407C and the like. An ejector-type refrigeration cycle that employs these refrigerants constitutes a subcritical refrigeration cycle.

(Second Embodiment)
The ejector 113 of the present embodiment is applied to the ejector type refrigeration cycle 10 having the same configuration as that of the first embodiment. The ejector type refrigerating cycle 10 of the present embodiment is applied to a stationary heating / hot water supply device, and heats the blown air or hot water supplied to the room. The ejector type refrigeration cycle 10 of the present embodiment uses carbon dioxide as a refrigerant, and constitutes a supercritical refrigeration cycle in which the refrigerant pressure on the high pressure side exceeds the critical pressure of the refrigerant.

Therefore, the radiator 12 of the ejector type refrigeration cycle 10 of the present embodiment heat-exchanges the high-pressure refrigerant with the blown air blown to the air-conditioned space or the hot water supplied to the kitchen, bath, or the like to exchange heat with the high-pressure refrigerant. It is a heat exchanger for heat dissipation that dissipates heat in a supercritical state. Further, the evaporator 16 of the present embodiment is an endothermic heat exchanger that exchanges heat between the low pressure refrigerant and the outside air blown by the outside air fan to evaporate the low pressure refrigerant and exert a heat absorbing action.

As shown in FIG. 11, the ejector 113 of the present embodiment has a drive side nozzle portion 131, a body portion 132, a needle valve 133, and a drive mechanism 134. In the drive-side nozzle unit 131, the dimensional specifications of each portion are set so that the drive-side nozzle unit 31 described in the first embodiment has the same function. A needle valve 133 is arranged in the refrigerant passage of the drive-side nozzle portion 131.

The needle valve 133 changes the passage cross-sectional area of the throat portion of the drive side nozzle portion 131 and the drive side injection port by being displaced in the axial direction of the drive side nozzle portion 131. The needle valve 133 is made of a metal (stainless steel in this embodiment) needle-shaped member. The central axis of the needle valve 133 is arranged coaxially with the central axis of the drive-side nozzle portion 131. The opposite end of the drive-side injection port of the needle valve 133 is connected to the drive mechanism 134.

The drive mechanism 134 is a drive unit that displaces the needle valve 133 in the central axis direction. In this embodiment, a stepping motor is adopted as the drive mechanism 134. The operation of the drive mechanism 134 is controlled by a control signal (that is, a control pulse) output from the control device 20.

The body portion 132 is formed by combining a plurality of metal (in this embodiment, aluminum) block members. The dimensional specifications of each part of the body part 132 are set so as to exhibit the same function as the body part 32 described in the first embodiment. The body portion 132 has the same refrigerant suction port 321 as in the first embodiment, a suction side nozzle portion 322, a mixing portion 323, and a diffuser portion 324.

The configuration of the other ejectors 113 is the same as that of the ejector 13 described in the first embodiment.

Next, the operation of the ejector type refrigeration cycle 10 of the present embodiment will be described. In the present embodiment, the control device 20 controls the operation of the drive mechanism 134 so that the superheat degree of the refrigerant on the outlet side of the evaporator 16 approaches a predetermined reference superheat degree KSH. Other operations are the same as in the first embodiment. Therefore, the same effect as that of the first embodiment can be obtained in the ejector type refrigeration cycle 10 of the present embodiment.

That is, according to the ejector 113 of the present embodiment, high boosting ability can be exhibited regardless of load fluctuation. As a result, even in the ejector type refrigeration cycle 10 of the present embodiment, high COP can be exhibited regardless of the load fluctuation.

Further, in the ejector type refrigeration cycle 10 in which carbon dioxide or a mixed refrigerant containing carbon dioxide is used as the refrigerant, the present inventors exhibit a high boosting ability by using a shock wave under the following conditions. I have confirmed that.

Specifically, it has been confirmed that the ejector 13 exhibits a high boosting ability at least within a range in which the inlet pressure Pin and the outlet pressure Pout of the ejector 13 satisfy both of the following formulas F12 and F13.
6 ≤ Pin ≤ 14 (MPa) ... (F12)
1.5 ≤ Pout ≤ 7 (MPa) ... (F13)
Further, it has been confirmed that the ejector 13 exhibits a high boosting ability at least within a range in which the inlet pressure Pin and the drive side injection pressure Pnzout of the ejector 13 satisfy the following formula F14.
0.3 ≤ Pnzout / Pin ≤ 0.7 ... (F14)
In the ejector type refrigeration cycle that employs carbon dioxide or a mixed refrigerant containing carbon dioxide, a supercritical refrigeration cycle is configured.

(Third Embodiment)
In this embodiment, as shown in FIG. 12, an example in which the ejector 13 is applied to the ejector type refrigeration cycle 10a will be described. The ejector type refrigeration cycle 10a is applied to an air conditioner for vehicles. The ejector type refrigeration cycle 10a includes a branch portion 17, a first evaporator 161 and a second evaporator 162. Further, in the ejector type refrigeration cycle 10a, the accumulator 14 is abolished.

The branch portion 17 is a three-way joint that branches the flow of the refrigerant flowing out of the radiator 12. The drive-side inlet 31a side of the drive-side nozzle portion 31 of the ejector 13 is connected to one of the outlets of the branch portion 17. The inlet side of the fixed throttle 15 is connected to the other outlet of the branch portion 17.

The refrigerant inlet side of the first evaporator 161 is connected to the outlet of the diffuser portion 324 of the ejector 13. The first evaporator 161 is an endothermic heat exchanger that cools the blown air by exchanging heat between the low-pressure refrigerant flowing out of the diffuser portion 324 of the ejector 13 and the blown air blown from the indoor blower 16a. The suction port side of the compressor 11 is connected to the refrigerant outlet of the first evaporator 161.

The refrigerant inlet side of the second evaporator 162 is connected to the outlet of the fixed throttle 15. The second evaporator 162 is an endothermic heat exchanger that cools the blown air by exchanging heat between the low-pressure refrigerant decompressed by the fixed throttle 15 and the blown air after passing through the first evaporator 161. The refrigerant suction port 321 side of the ejector 13 is connected to the refrigerant outlet of the second evaporator 162.

The first evaporator 161 and the second evaporator 162 of this embodiment are integrally configured. Specifically, the first evaporator 161 and the second evaporator 162 are composed of a so-called tank-and-tube type heat exchanger. A tank-and-tube heat exchanger is a heat exchanger having a plurality of tubes for circulating a refrigerant and a pair of collecting and distributing tanks connected to both ends of the plurality of tubes to collect or distribute the refrigerant. be.

The first evaporator 161 and the second evaporator 162 are integrally configured by forming the collective distribution tank with the same member. In the present embodiment, the first evaporator 161 and the second evaporator 162 are arranged in series with respect to the blown air flow so that the first evaporator 161 is arranged on the upstream side of the blown air flow with respect to the second evaporator 162. It is placed in. Therefore, the blown air flows as shown by the dashed arrow in FIG. 12.

The configurations of the other ejector type refrigeration cycle 10a and the ejector 13 are the same as those of the first embodiment.

Next, the operation of the ejector type refrigeration cycle 10a of the present embodiment in the above configuration will be described. In the ejector type refrigeration cycle 10a, when the control device 20 operates the compressor 11, the high-temperature high-pressure refrigerant discharged from the compressor 11 is condensed by the radiator 12 as in the first embodiment. The refrigerant flowing out of the radiator 12 flows into the branch portion 17. At the branch portion 17, the flow of the refrigerant flowing out of the radiator 12 is branched.

One of the refrigerants branched at the branch portion 17 flows into the drive side nozzle portion 31 of the ejector 13 as the drive side refrigerant. In the drive-side nozzle unit 31, the drive-side refrigerant is issentropically depressurized as in the first embodiment. Then, the drive-side injection refrigerant in the gas-liquid two-phase state exceeding the two-phase sound velocity is injected from the drive-side injection port 31e of the drive-side nozzle unit 31 into the mixing space 323a of the mixing unit 323.

Further, due to the suction action of the drive-side injection refrigerant, the refrigerant flowing out from the second evaporator 162 is sucked into the suction space 321a from the refrigerant suction port 321 as the suction-side refrigerant. The suction side refrigerant sucked into the suction space 321a flows into the suction side nozzle portion 322. In the suction side nozzle unit 322, the suction side injection refrigerant is injected from the suction side injection port 322a of the suction side nozzle unit 322 into the mixing space 323a of the mixing unit 323, as in the first embodiment.

In the mixing unit 323, the pressure of the mixed refrigerant of the driving side injection refrigerant and the suction side injection refrigerant increases due to the pressure recovery action of the shock wave generated by the drive side injection refrigerant. The mixed refrigerant flowing out of the mixing section 323 flows into the diffuser section 324. In the diffuser unit 324, the pressure of the mixed refrigerant further increases, as in the first embodiment.

The refrigerant flowing out of the diffuser unit 324 flows into the first evaporator 161. In the first evaporator 161 the refrigerant flowing out from the diffuser unit 324 absorbs heat from the blown air blown by the indoor blower 16a and evaporates. As a result, the blown air is cooled. The vapor phase refrigerant flowing out of the first evaporator 161 is sucked into the compressor 11 and compressed again.

On the other hand, the other refrigerant branched at the branch portion 17 flows into the fixed throttle 15 and is enthalpy depressurized. The low-pressure refrigerant decompressed by the fixed throttle 15 flows into the second evaporator 162. The refrigerant flowing into the second evaporator 162 absorbs heat from the blown air after passing through the first evaporator 161 and evaporates. As a result, the blown air is further cooled and blown into the vehicle interior. The refrigerant flowing out of the second evaporator 162 is sucked from the refrigerant suction port 321 of the ejector 13.

The ejector type refrigerating cycle 10a of the present embodiment operates as described above and can cool the blown air blown into the vehicle interior.

In the ejector type refrigeration cycle 10a, the refrigerant evaporation temperature of the first evaporator 161 can be raised higher than the refrigerant evaporation temperature of the second evaporator 162 by the pressurizing action of the ejector 13. Therefore, in the ejector type refrigeration cycle 10a, the temperature difference between the refrigerant evaporation temperature of the first evaporator 161 and the blown air and the temperature difference between the refrigerant evaporation temperature of the second evaporator 162 and the blown air are ensured efficiently. Blower air can be cooled.

Further, in the ejector type refrigeration cycle 10a of the present embodiment, since the ejector 13 is adopted, high COP can be exhibited regardless of the load fluctuation.

The present disclosure is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present disclosure.

In the above-described embodiment, an example in which the ejectors 13 and 113 according to the present disclosure are applied to the ejector type refrigeration cycles 10 and 10a has been described, but the cycles to which the ejectors 13 and 113 can be applied are not limited to this. For example, it may be applied to a cycle in which an intermediate pressure expansion valve is added to the ejector type refrigeration cycle 10.

The intermediate pressure expansion valve decompresses the refrigerant flowing out of the radiator 12 in the ejector type refrigeration cycle 10 and causes the refrigerant to flow out to the drive side inlet 31a side of the drive side nozzle portion 31 of the ejector 13. As the intermediate pressure expansion valve, a variable expansion mechanism that changes the throttle opening so that the pressure of the high pressure refrigerant flowing into the intermediate pressure expansion valve becomes the target high pressure determined according to the temperature of the high pressure refrigerant can be adopted. can.

Further, it may be applied to a cycle in which an intermediate pressure expansion valve is added to the ejector type refrigeration cycle 10a.

The intermediate pressure expansion valve decompresses the refrigerant flowing out of the radiator 12 in the ejector type refrigeration cycle 10a and causes it to flow out to the inflow port side of the branch portion 17. As the intermediate pressure expansion valve, a variable throttle mechanism that changes the throttle opening so that the superheat degree of the refrigerant flowing out of the first evaporator 161 approaches a predetermined reference superheat degree can be adopted.

Further, in the above-mentioned third embodiment, an example in which the first evaporator 161 and the second evaporator 162 of the ejector type refrigeration cycle 10a are integrally configured has been described, but the first evaporator 161 and the second evaporator 162 have been described. May be formed separately. Then, the first evaporator 161 and the second evaporator 162 may cool the different refrigerant target fluids in different temperature zones.

Since the ejectors 13 and 113 exhibit high boosting ability regardless of load fluctuations, for example, the first evaporator 161 whose refrigerant evaporation temperature is higher than that of the second evaporator 162 is used for air conditioning to be blown to the air conditioning target space. It may be used to blow air. Then, the second evaporator 162, in which the refrigerant evaporation temperature is lower than that of the first evaporator 161 may be used to cool the blown air for the freezer that is circulated and blown into the freezer.

The configurations of the ejector type refrigeration cycles 10 and 10a are not limited to those disclosed in the above-described embodiment.

For example, the compressor 11 is not limited to the electric compressor. For example, when the ejector type refrigeration cycles 10 and 10a are applied to a vehicle equipped with an engine, an engine drive type compressor driven by a rotational driving force transmitted from the engine may be adopted. In the ejector type refrigeration cycle, as the engine drive type compressor, a variable capacity type compressor or the like whose refrigerant discharge capacity can be adjusted by changing the discharge capacity can be adopted.

Further, a so-called subcool type condenser may be adopted as the radiator 12 of the ejector type refrigeration cycle constituting the subcritical refrigeration cycle.

The subcool type condenser has a condensing part, a receiver part, and a supercooling part. The condensing unit exchanges heat between the refrigerant and the outside air to condense the refrigerant. The receiver unit separates the gas and liquid of the refrigerant flowing out from the condensing unit, and stores a part of the separated liquid phase refrigerant as a surplus refrigerant in the cycle. The supercooling unit supercools the liquid phase refrigerant by exchanging heat between the liquid phase refrigerant flowing out from the receiver unit and the outside air.

Further, the means disclosed in each of the above embodiments may be appropriately combined to the extent practicable. For example, the ejector 113 described in the second embodiment may be applied to the ejector type refrigeration cycle 10a described in the third embodiment.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

Claims (9)

1. An ejector applied to refrigeration cycle equipment.
   The drive-side nozzles (31, 131) that inject the drive-side injection refrigerant in a gas-liquid two-phase state by decompressing the drive-side refrigerant and accelerating it to supersonic speed.
   A refrigerant suction port (321) that sucks the suction side refrigerant, a suction side nozzle portion (322) that depressurizes and injects the suction side refrigerant sucked from the refrigerant suction port, and a suction side ejected from the suction side nozzle portion. A body unit (32,) having a mixing unit (323) for mixing the injection refrigerant and the drive-side injection refrigerant, and a diffuser unit (324) for converting the kinetic energy of the mixed refrigerant mixed in the mixing unit into pressure energy. 132) and
   The drive-side injection port (31e) of the drive-side nozzle portion and the suction-side injection port (322a) of the suction-side nozzle portion have directions in which the injection direction of the drive-side injection refrigerant and the injection direction of the suction-side injection refrigerant are the same. It is open so that
   The pressure of the drive-side injection refrigerant is higher than the pressure of the suction-side injection refrigerant.
   The mixed refrigerant flowing out of the mixing section and flowing into the diffuser section is an ejector in which the refrigerant pressure on the central axis side and the refrigerant pressure on the wall surface side match and are subsonic.
2. When the passage cross-sectional area of the outlet of the mixing portion is defined as the mixing portion outlet area Augustout, and the passage cross-sectional area of the outlet of the diffuser portion is defined as the diffuser portion outlet area Aout,
   The flow velocity of the mixed refrigerant flowing into the diffuser section is subsonic.
   Amixout / Aout
   The ejector according to claim 1, wherein is set.
3. The axial length from the inlet to the outlet of the mixing section is defined as the mixing section distance L, and the axial length required for the drive-side injection refrigerant to extinguish the shock wave generated in the mixing section is defined as the mixing section distance L. When defined as relaxation distance Lv,
   Lv <L
   The ejector according to claim 1 or 2.
   However, the relaxation distance Lv is defined by the following mathematical formula.
   Lv = U ₀ × (ρ _L × D _L ² ) / (18 × μ _G )
   U _0: average mass flow rate [rho _L of the mixed refrigerant in the most upstream portion of the shock wave: Density D of the droplet of the mixed refrigerant at the most upstream portion of the shock waves _L: the mixed refrigerant at the most upstream portion of the shockwave Droplet diameter μ _G : Viscosity of the gas phase refrigerant in the mixed refrigerant at the most upstream part of the shock wave.
4. When the Mach number of the mixed refrigerant in the most upstream part of the shock wave is defined as the _{initial Mach number M 0,}
   1 <M ₀ <2.5
   1 <L / Lv ≦ 3.5
   The ejector according to claim 3.
5. When the Mach number of the mixed refrigerant in the most upstream portion of the shock wave _{is defined as the initial Mach number M 0,} and the diameter of the refrigerant inlet of the mixing portion is defined as the mixing portion inlet diameter Dmix,
   1 <M ₀ <2.5
   1 <L / Dmix ≦ 10
   The ejector according to claim 3.
6. The ejector according to claim 4 or 5, wherein the mixing portion is formed in a shape in which the cross-sectional area of the passage increases as the mixed refrigerant moves toward the downstream side in the flow direction.
7. The ejector according to any one of claims 1 to 6, wherein the drive-side nozzle portion accelerates so that the gas phase refrigerant in the refrigerant passage formed inside accelerates to be equal to or lower than the gas phase sound velocity.
8. The drive-side nozzle portion has a throat portion (31c) that reduces the refrigerant passage cross-sectional area most, and a divergent portion (31d) that expands the passage cross-sectional area as it goes from the throat portion to the drive-side injection port. ,
   When the passage cross-sectional area of the throat is defined as the throat area Anzth and the passage cross-sectional area of the drive-side injection port is defined as the drive-side injection port area Anzout,
   The speed of the gas phase refrigerant in the refrigerant passage is set to be equal to or lower than the gas phase sound velocity.
   Anzout / Anzth
   The ejector according to claim 7, wherein is set.
9. When the passage cross-sectional area of the drive-side injection port is defined as the drive-side injection port area Anzout, and the passage cross-sectional area of the suction-side injection port is defined as the suction-side injection port area Asnout,
   The refrigerant pressure of the drive-side injection refrigerant is higher than the refrigerant pressure of the suction-side injection refrigerant.
   Asnout / Anzout
   The ejector according to any one of claims 1 to 8, wherein is set.

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