JP5962571B2 - Ejector - Google Patents

Description

  The present invention relates to an ejector that sucks a fluid by reducing the pressure of the fluid and sucking a jet fluid ejected at a high speed.

  Conventionally, an ejector is known as a decompression device applied to a vapor compression refrigeration cycle apparatus. This type of ejector has a nozzle part that decompresses the refrigerant, sucks the gas-phase refrigerant that has flowed out of the evaporator by the suction action of the jetted refrigerant jetted from the nozzle part, and injects it at the booster (diffuser part) The pressure can be increased by mixing the refrigerant and the suction refrigerant.

  Therefore, in a refrigeration cycle apparatus including an ejector as a decompression device (hereinafter referred to as an ejector-type refrigeration cycle), the power consumption of the compressor can be reduced by utilizing the refrigerant pressure-increasing action in the pressure boosting section of the ejector. The coefficient of performance (COP) of the cycle can be improved as compared with a normal refrigeration cycle apparatus including an expansion valve or the like.

  Furthermore, Patent Document 1 discloses an ejector that is applied to an ejector-type refrigeration cycle and that has a nozzle portion that depressurizes the refrigerant in two stages. More specifically, in the ejector disclosed in Patent Document 1, the refrigerant in the high-pressure liquid phase is decompressed by the first nozzle until the gas-liquid two-phase state is obtained, and the refrigerant in the gas-liquid two-phase state is supplied to the second nozzle. Inflow.

  Thereby, in the ejector of patent document 1, the boiling of the refrigerant | coolant in a 2nd nozzle is accelerated | stimulated, the nozzle efficiency as the whole nozzle part is improved, and it is going to aim at the further improvement of COP as the whole ejector type refrigeration cycle. Yes.

  Moreover, in a general ejector, the diffuser part (pressure | voltage rise part) is arrange | positioned coaxially on the extension line | wire of the axial direction of a nozzle part. Further, Patent Document 2 describes that the ejector efficiency can be improved by relatively reducing the spread angle of the diffuser portion arranged in this way.

  The nozzle efficiency is the energy conversion efficiency when the pressure energy of the refrigerant is converted into kinetic energy in the nozzle portion, and the ejector efficiency is the energy conversion efficiency of the entire ejector.

Japanese Patent No. 3331604 JP 2003-14318 A

  However, in the ejector of Patent Document 1, for example, when the thermal load of the ejector-type refrigeration cycle becomes low, and the pressure difference (high-low pressure difference) between the pressure of the high-pressure side refrigerant and the pressure of the low-pressure side refrigerant in the cycle is reduced, There is a case where the first nozzle is depressurized by a high-low pressure difference, and the refrigerant is hardly depressurized by the second nozzle.

  In such a case, the nozzle efficiency improvement effect due to the flow of the gas-liquid two-phase refrigerant into the second nozzle cannot be obtained, and the refrigerant cannot be sufficiently boosted in the diffuser section.

  On the other hand, by applying the diffuser portion having a relatively small spread angle disclosed in Patent Literature 2 to the ejector of Patent Literature 1 and improving the ejector efficiency, the diffuser portion is also at a low load of the ejector refrigeration cycle. A means for sufficiently increasing the pressure of the refrigerant can be considered.

  However, when such a diffuser portion is applied, the length of the nozzle portion in the axial direction as a whole becomes longer, so that the size of the ejector becomes unnecessarily large at the normal load of the ejector refrigeration cycle. Is a problem.

On the other hand, the inventors of the present invention previously described in Japanese Patent Application No. 2012-184950 (hereinafter referred to as a prior application example).
An ejector applied to an ejector refrigeration cycle,
A swirling space for swirling the refrigerant flowing out of the radiator, a decompression space for depressurizing the refrigerant flowing out of the swirling space, and a suction passage for sucking the refrigerant flowing out of the evaporator in communication with the refrigerant flow downstream side of the depressurizing space , And a body formed with a pressure increasing space for increasing the pressure by mixing the refrigerant injected from the pressure reducing space and the suction refrigerant sucked from the suction passage;
A passage forming member that is at least partially disposed in the decompression space and in the pressurization space and is formed in a conical shape whose cross-sectional area expands with distance from the decompression space;
Nozzle passage functioning as a nozzle in which a refrigerant passage formed between an inner peripheral surface of a portion of the body forming a decompression space and an outer peripheral surface of the passage forming member decompresses and injects the refrigerant flowing out of the swirling space. Form the
A refrigerant passage formed between an inner peripheral surface of a part of the body that forms a pressure increasing space and an outer peripheral surface of the passage forming member serves as a diffuser passage that functions as a diffuser that increases the pressure by mixing the injected refrigerant and the suction refrigerant. Forming,
In the nozzle passage, we propose an ejector with a minimum passage area that has the smallest refrigerant passage area, and a divergent portion that gradually increases the refrigerant passage area from the smallest passage area to the refrigerant outlet of the nozzle passage. doing.

  In the ejector of this prior application example, the refrigerant is swirled in the swirling space, so that the refrigerant pressure on the swirling center side in the swirling space becomes the pressure that becomes the saturated liquid phase refrigerant, or the refrigerant boils under reduced pressure (causes cavitation) It can be reduced until pressure is reached. As a result, a larger amount of gas-phase refrigerant exists on the inner circumference side than the outer circumference side of the swivel center axis, and the refrigerant in the swirl space is divided into a gas single phase around the swirl center line and a liquid single phase around it. Phase separation can be achieved.

  When the refrigerant in the two-phase separation state is caused to flow into the nozzle passage, boiling is promoted by wall surface boiling and interface boiling, so that the gas phase and the liquid phase are homogeneous in the vicinity of the minimum passage area of the nozzle passage. It is possible to obtain an ideal gas-liquid mixed state mixed in the above. Furthermore, the refrigerant in the ideal gas-liquid mixed state is blocked (choking), and the flow rate of the refrigerant can be accelerated until it becomes equal to or higher than the two-phase sound speed.

  Then, the supersonic state refrigerant that has been accelerated until it becomes equal to or higher than the two-phase sound speed can be further accelerated at the divergent portion disposed downstream of the minimum passage area portion. Thereby, the energy conversion efficiency (equivalent to the nozzle efficiency of a prior art) at the time of converting the pressure energy of a refrigerant | coolant into speed energy in a nozzle channel | path can be improved.

  Further, in the ejector of the prior application example, the passage forming member is formed in a conical shape whose cross-sectional area increases with the distance from the decompression space, and the shape of the diffuser passage is separated from the decompression space. The shape is widened along the outer periphery of the passage forming member. Thereby, it can suppress that the axial direction dimension of a diffuser channel | path is expanded, and the enlargement of the physique as the whole ejector can be suppressed.

  That is, according to the ejector of the prior application example, high energy conversion efficiency can be exhibited regardless of the load fluctuation of the ejector refrigeration cycle without increasing the size of the physique.

  The inventors of the present invention have studied the ejector of the prior application in order to further improve the energy conversion efficiency of the ejector. In the ejector of the prior application, the ejector refrigeration cycle is not affected by load fluctuations. Although high energy conversion efficiency can be exhibited, desired energy conversion efficiency may not be obtained depending on operating conditions.

  Therefore, the present inventors investigated the cause, and in the ejector of the prior application example, the two-phase separated refrigerant in which the gas-phase refrigerant is unevenly distributed on the turning center side and the liquid-phase refrigerant is unevenly distributed on the outer peripheral side is supplied to the nozzle passage. It was found that it was caused to flow into The reason is that if such a two-phase separated refrigerant flows into the nozzle passage, it becomes difficult for boiling nuclei to be supplied to the liquid phase refrigerant that is unevenly distributed on the outer peripheral side, and the liquid phase refrigerant that is unevenly distributed on the outer peripheral side is boiled. This is because a delay occurs.

  That is, if a boiling delay occurs in the liquid refrigerant that is unevenly distributed on the outer peripheral side, the refrigerant that has flowed into the nozzle passage is unlikely to be in an ideal gas-liquid mixed state, and the refrigerant that has flowed into the nozzle passage is at a two-phase sound speed or higher. However, it becomes the downstream of the minimum passage area part, that is, the inside of the divergent part. For this reason, in the range of the refrigerant passage in the divergent portion from the minimum passage area portion to the location where the refrigerant is more than the two-phase sonic speed, it is not only possible to accelerate the supersonic refrigerant, but also due to the expansion of the refrigerant passage area The refrigerant in the subsonic speed state (flow velocity lower than the two-phase sound speed) is decelerated.

  As a result, under operating conditions that cause boiling delay in the liquid phase refrigerant, the entire region of the divergent part cannot be effectively used to accelerate the refrigerant, and the energy conversion efficiency in the nozzle passage is lower than the desired value. It will decline.

  In view of the above points, an object of the present invention is to suppress a decrease in energy conversion efficiency of an ejector that decompresses a refrigerant in a gas-liquid mixed state.

The present invention has been devised to achieve the above object, and in the invention described in claim 1, an ejector applied to the vapor compression refrigeration cycle apparatus (10),
A swirling space (30a) for swirling the refrigerant flowing in from the refrigerant inlet (31a), a decompression space (30b) for decompressing the refrigerant flowing out of the swirling space (30a), and a refrigerant flow downstream of the decompression space (30b). A suction passage (13b) that communicates and sucks refrigerant from the outside, and a pressurization space (30e) that mixes the refrigerant injected from the decompression space (30b) and the suction refrigerant sucked from the suction passage (13b). ) Is formed, and at least a part of the body (30) is disposed in the decompression space (30b) and the boosting space (30e), and the body (30) is disconnected as the distance from the decompression space (30b) increases. A passage forming member (35) formed in a conical shape with an increased area,
The refrigerant passage formed between the inner peripheral surface of the part forming the decompression space (30b) in the body (30) and the outer peripheral surface of the passage forming member (35) is a refrigerant that has flowed out of the swirling space (30a). Is a nozzle passage (13a) that functions as a nozzle for depressurizing and injecting, between the inner peripheral surface of the body (30) forming the pressurizing space (30e) and the outer peripheral surface of the passage forming member (35) The refrigerant passage formed between them is a diffuser passage (13c) that functions as a diffuser that increases the pressure by mixing the injected refrigerant and the suction refrigerant,
Further, the nozzle passage (13a) is provided on the downstream side of the refrigerant flow of the minimum passage area portion (30m) having the smallest refrigerant passage area and the minimum passage area portion (30m) to reduce the speed component in the swirling direction of the refrigerant. And a divergent portion (133) in which the refrigerant passage area gradually increases from the outlet side of the homogenizing portion (132) toward the downstream side of the refrigerant flow.

  According to this, by turning the refrigerant in the swirling space (30a), the refrigerant pressure on the turning center side of the swirling space (30a) can be reduced to a pressure at which the refrigerant boils under reduced pressure (causes cavitation). . And the gas-liquid mixing which the gaseous-phase refrigerant | coolant and the liquid phase refrigerant mixed in the nozzle channel | path (13a) by flowing the refrigerant | coolant of the two-phase separation state of the rotation center side of a rotation space (30a) into a nozzle channel | path (13a). The refrigerant in the state can be depressurized.

  Furthermore, since the homogenization part (132) is formed in the nozzle passage (13a), the speed component in the swirling direction of the refrigerant can be reduced in the homogenization part (132). As a result, the gas phase and the liquid phase are homogenized from the inhomogeneous gas-liquid mixed state in which the gas phase refrigerant is unevenly distributed on the turning center side and the liquid phase refrigerant is unevenly distributed on the outer peripheral side. It is possible to obtain an ideal gas-liquid mixed state mixed in the above.

  Then, the refrigerant that has become an ideal gas-liquid mixed state in the homogenizing section (132) is blocked (choking), and the refrigerant is accelerated until the flow velocity of the refrigerant becomes equal to or higher than the two-phase sound speed. In 31f), the supersonic refrigerant can be accelerated.

  As a result, the flow velocity of the refrigerant injected from the nozzle passage (13a) can be effectively increased, and the pressure energy of the refrigerant is increased in the nozzle passage (13a) of the ejector that depressurizes the refrigerant in the gas-liquid mixed state. It can suppress that the energy conversion efficiency (equivalent to the nozzle efficiency of a prior art) at the time of converting into energy falls.

  Note that an ideal gas-liquid mixed state in which the gas phase and the liquid phase are homogeneously mixed is a liquid phase refrigerant (for example, an inner wall surface side of the nozzle passage, etc.) with no liquid droplets ( It can be defined as a state in which the particles are in the form of liquid phase refrigerant and are uniformly distributed in the gas phase refrigerant. Further, in an ideal gas-liquid mixed state in which the gas phase and the liquid phase are homogeneously mixed, the flow rate of the droplets and the flow rate of the gas phase refrigerant are equal.

  Further, in the present claim, the passage forming member (35) is not limited to a shape that is strictly formed with a shape in which the cross-sectional area expands with distance from the decompression space (30b), and at least a part thereof. The shape of the diffuser passage (13c) is made to expand outward as it moves away from the decompression space (30b) by including a shape in which the cross-sectional area increases as it moves away from the decompression space (30b). Including those that can.

  Further, “conically formed” is not limited to the meaning that the passage forming member (35) is formed in a complete conical shape, but a shape close to a cone or a shape including a conical shape in part. Or, it includes the meaning that the shape is a combination of a conical shape, a cylindrical shape, and a truncated cone shape. Specifically, the shape in which the axial cross-sectional shape is not limited to an isosceles triangle, the shape in which the two sides sandwiching the apex are convex on the inner peripheral side, the shape in which the two sides sandwiching the apex are convex on the outer peripheral side, Furthermore, it is meant to include those having a semicircular cross section.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a typical whole block diagram of the ejector-type refrigerating cycle of 1st Embodiment. It is an axial sectional view of the ejector of the first embodiment. It is typical sectional drawing for demonstrating the function of each refrigerant path of the ejector of 1st Embodiment. It is a typical expanded sectional view of the X section of FIG. It is a Mollier diagram which shows the state of the refrigerant | coolant in the ejector-type refrigerating cycle of 1st Embodiment. It is a graph which shows the change of the refrigerant passage area of the nozzle channel | path of the ejector of 1st Embodiment, wall surface pressure, and axial speed. It is drawing corresponding to FIG. 4 in the ejector of 2nd Embodiment. It is explanatory drawing for demonstrating the expansion angle at the time of converting the homogenization space of the ejector of other embodiment into a truncated cone shape.

(First embodiment)
1st Embodiment of this invention is described using FIGS. As shown in the overall configuration diagram of FIG. 1, the ejector 13 of this embodiment is applied to a refrigeration cycle apparatus including an ejector as a refrigerant decompression unit, that is, an ejector refrigeration cycle 10. Furthermore, this ejector type refrigeration cycle 10 is applied to a vehicle air conditioner, and fulfills a function of cooling the blown air blown into the vehicle interior, which is the air-conditioning target space.

  The ejector refrigeration cycle 10 employs an HFC refrigerant (specifically, R134a) as a refrigerant, and constitutes a vapor compression subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. doing. Of course, you may employ | adopt HFO type refrigerant | coolants (for example, R1234yf). Furthermore, refrigeration oil for lubricating the compressor 11 is mixed in the refrigerant, and a part of the refrigeration oil circulates in the cycle together with the refrigerant.

  In the ejector-type refrigeration cycle 10, the compressor 11 sucks the refrigerant and discharges it until it becomes high-pressure refrigerant. Specifically, the compressor 11 of the present embodiment is an electric compressor configured by housing a fixed capacity type compression mechanism 11a and an electric motor 11b for driving the compression mechanism 11a in one housing.

  As the compression mechanism 11a, various compression mechanisms such as a scroll-type compression mechanism and a vane-type compression mechanism can be employed. Further, the electric motor 11b is controlled in its operation (number of rotations) by a control signal output from a control device to be described later, and may adopt either an AC motor or a DC motor.

  The compressor 11 may be an engine-driven compressor that is driven by a rotational driving force transmitted from a vehicle travel engine via a pulley, a belt, or the like. This type of engine-driven compressor includes a variable displacement compressor that can adjust the refrigerant discharge capacity by changing the discharge capacity, and a fixed type that adjusts the refrigerant discharge capacity by changing the operating rate of the compressor by intermittently connecting the electromagnetic clutch. A capacity type compressor or the like can be employed.

  The refrigerant inlet side of the condenser 12 a of the radiator 12 is connected to the discharge port side of the compressor 11. The radiator 12 is a heat exchanger for heat radiation that radiates and cools the high-pressure refrigerant by exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and outside air (outside air) blown by the cooling fan 12d. .

  More specifically, the radiator 12 is a condensing unit that exchanges heat between the high-pressure gas-phase refrigerant discharged from the compressor 11 and the outside air blown from the cooling fan 12d to radiate and condense the high-pressure gas-phase refrigerant. 12a, a receiver 12b that separates the gas-liquid refrigerant flowing out of the condensing unit 12a and stores excess liquid-phase refrigerant, and a liquid-phase refrigerant that flows out of the receiver unit 12b and the outside air blown from the cooling fan 12d exchange heat. This is a so-called subcool condenser that includes a supercooling section 12c that supercools the liquid-phase refrigerant.

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

  The ejector 13 functions as a refrigerant pressure reducing means for reducing the pressure of the supercooled high-pressure liquid-phase refrigerant that has flowed out of the radiator 12 and flowing it to the downstream side, and is described later by the suction action of the refrigerant flow injected at a high speed. It functions as a refrigerant circulating means (refrigerant transporting means) that sucks (transports) and circulates the refrigerant flowing out of the evaporator 14 that circulates. Furthermore, the ejector 13 according to the present embodiment also functions as a gas-liquid separation unit that separates the gas-liquid of the decompressed refrigerant.

  A specific configuration of the ejector 13 will be described with reference to FIGS. In addition, the up and down arrows in FIG. 2 indicate the up and down directions in a state where the ejector refrigeration cycle 10 is mounted on the vehicle air conditioner. 3 and 4 are schematic cross-sectional views for explaining the function and shape of each refrigerant passage of the ejector 13, and the same parts as those in FIG. 2 are denoted by the same reference numerals.

  First, the ejector 13 of this embodiment is provided with the body 30 comprised by combining a some structural member, as shown in FIG. Specifically, the body 30 includes a housing body 31 that is formed of a prismatic or cylindrical metal or resin and forms an outer shell of the ejector 13. A nozzle body 32 is provided inside the housing body 31. The middle body 33, the lower body 34, etc. are fixed.

  The housing body 31 includes a refrigerant inlet 31 a that allows the refrigerant flowing out of the radiator 12 to flow into the interior, a refrigerant suction port 31 b that sucks the refrigerant flowing out of the evaporator 14, and a gas-liquid separation space formed inside the body 30. The liquid-phase refrigerant outlet 31c that causes the liquid-phase refrigerant separated in 30f to flow out to the refrigerant inlet side of the evaporator 14 and the gas-phase refrigerant separated in the gas-liquid separation space 30f flow out to the suction side of the compressor 11. The gas-phase refrigerant outlet 31d to be made is formed.

  The nozzle body 32 is formed of a substantially conical metal member or the like tapering in the refrigerant flow direction, and is press-fitted into the housing body 31 so that the axial direction is parallel to the vertical direction (vertical direction in FIG. 2). It is fixed by means of Between the upper side of the nozzle body 32 and the housing body 31, a swirling space 30a for swirling the refrigerant flowing from the refrigerant inlet 31a is formed.

  The swirling space 30a is formed in a rotating body shape, and the central axis shown by the one-dot chain line in FIG. 2 extends in the vertical direction. The rotating body shape is a three-dimensional shape formed when a plane figure is rotated around one straight line (central axis) on the same plane. More specifically, the swirl space 30a of the present embodiment is formed in a substantially cylindrical shape. Of course, you may form in the shape etc. which combined the cone or the truncated cone, and the cylinder.

  Furthermore, the refrigerant inflow passage 31e that connects the refrigerant inlet 31a and the swirling space 30a extends in the tangential direction of the inner wall surface of the swirling space 30a when viewed from the central axis direction of the swirling space 30a. Thereby, the refrigerant that has flowed into the swirl space 30a from the refrigerant inflow passage 31e flows along the inner wall surface of the swirl space 30a and swirls in the swirl space 30a.

  The refrigerant inflow passage 31e does not need to be formed so as to completely coincide with the tangential direction of the swirl space 30a when viewed from the central axis direction of the swirl space 30a, and at least in the tangential direction of the swirl space 30a. As long as a component is included, it may be formed including a component in another direction (for example, a component in the axial direction of the swirling space 30a).

  Here, since centrifugal force acts on the refrigerant swirling in the swirling space 30a, the refrigerant pressure on the central axis side is lower than the refrigerant pressure on the outer peripheral side in the swirling space 30a. Therefore, in the present embodiment, during the normal operation of the ejector refrigeration cycle 10, the refrigerant pressure on the central axis side in the swirling space 30a is reduced to a pressure at which the refrigerant boils under reduced pressure (causes cavitation).

  Such adjustment of the refrigerant pressure on the central axis side in the swirling space 30a can be realized by adjusting the swirling flow velocity of the refrigerant swirling in the swirling space 30a. Further, the swirl flow rate can be adjusted by adjusting the area ratio between the passage sectional area of the refrigerant inflow passage 31e and the vertical sectional area in the axial direction of the swirling space 30a, for example. Note that the swirling flow velocity in the present embodiment means the flow velocity in the swirling direction of the refrigerant in the vicinity of the outermost peripheral portion of the swirling space 30a.

  Further, in the nozzle body 32, a decompression space 30b is formed in which the refrigerant that has flowed out of the swirl space 30a is decompressed and flows out downstream. The decompression space 30b is a columnar space or a truncated cone-shaped space that tapers downward, and gradually expands from the lower side of the cylindrical space or the tapered truncated cone-shaped space toward the refrigerant flow direction. It is formed in the shape of a rotating body combined with a frustoconical space, and the central axis of the decompression space 30b is arranged coaxially with the central axis of the swirling space 30a.

  Further, a passage forming member 35 that changes the passage area of the minimum passage area portion 30m while forming the smallest passage area portion 30m having the smallest refrigerant passage area in the decompression space 30b is formed in the decompression space 30b. The upper side is arranged. The passage forming member 35 is formed in a substantially conical shape that gradually expands toward the downstream side of the refrigerant flow, and the central axis thereof is arranged coaxially with the central axis of the decompression space 30b. In other words, the passage forming member 35 is formed in a conical shape whose cross-sectional area increases as the distance from the decompression space 30b increases.

  As shown in FIG. 3 and FIG. 4, the minimum passage area portion 30 m is provided between the inner peripheral surface of the part forming the pressure reducing space 30 b of the nozzle body 32 and the outer peripheral surface on the upper side of the passage forming member 35. Also, the tapered portion 131 arranged on the upstream side of the refrigerant flow, the homogenizing portion 132 arranged on the downstream side of the refrigerant flow with respect to the minimum passage area portion 30m, and the divergent portion arranged on the downstream side of the refrigerant flow with respect to the homogenizing portion 132 A refrigerant passage such as 133 is formed.

  In the tapered portion 131, the homogenizing portion 132, and the divergent portion 133, the pressure reducing space 30b and the passage forming member 35 are arranged in an overlapping manner when viewed from the radial direction. The shape of the vertical cross section in the axial direction is an annular shape (a donut shape excluding a small-diameter circular shape arranged coaxially from the circular shape).

  More specifically, the tapered portion 131 is a refrigerant passage that guides the cold that flows out of the swirl space 30a to the minimum passage area portion 30m, and the refrigerant passage area toward the downstream side of the refrigerant flow until reaching the minimum passage area portion 30m. Is formed into a shape that gradually decreases. A minimum passage area 30 m is disposed at the outlet of the tapered portion 131.

  Here, in the swirling space 30a of the present embodiment, the pressure of the refrigerant on the swirling center side is reduced and boiled under reduced pressure, so that the gas-phase refrigerant is unevenly distributed in the vicinity of the central axis of the swirling space 30a. Therefore, in the present embodiment, as shown in FIG. 4, the internal diameter of the portion of the nozzle body 32 that forms the minimum passage area 30m is made to be a gas phase refrigerant (hereinafter referred to as a columnar shape) that is unevenly distributed in a columnar shape during normal operation of the ejector refrigeration cycle 10. It is formed larger than the outer diameter of the air column.)

  The homogenizer 132 is a refrigerant passage having a constant refrigerant passage area. That is, the refrigerant passage area of the homogenizing portion 132 is equal to the refrigerant passage area in the minimum passage area portion 30m.

Furthermore, in this embodiment, the axial length when the shape of the homogenizing portion 132 is converted to a cylindrical shape in which the refrigerant passage area on the top surface and the bottom surface is equivalent to the refrigerant passage area of the minimum passage area portion 30 m is L. When the equivalent diameter of the refrigerant passage area in the minimum passage area portion 30m is D, the axial length L is set so as to satisfy the following formula F1.
0.1 ≦ L / D ≦ 6 (F1)
In the present embodiment, the axial length L is set so as to satisfy the above formula F1 even when the passage forming member 35 is displaced and the refrigerant passage area of the minimum passage area portion 30m changes.

  The divergent part 133 is formed in a shape in which the refrigerant passage area gradually increases from the outlet side of the homogenizing part 132 toward the downstream side of the refrigerant flow.

  In the present embodiment, a nozzle passage 13a that functions as a nozzle is a refrigerant passage formed between the inner peripheral surface of the decompression space 30b and the outer peripheral surface on the top side of the passage forming member 35 by such a passage shape. Further, in the nozzle passage 13a, the refrigerant is decompressed, and the flow rate of the refrigerant in the gas-liquid two-phase state is increased so as to be higher than the two-phase sound velocity, and is injected.

  Note that the refrigerant passage formed between the inner peripheral surface of the decompression space 30b and the outer peripheral surface on the top side of the passage forming member 35 in the present embodiment is as shown in the schematic enlarged sectional view of FIG. In addition, the refrigerant passage is formed in a range where a line segment extending in the normal direction from the outer peripheral surface of the passage forming member 35 intersects with a portion forming the decompression space 30b of the nozzle body 32.

  Moreover, since the refrigerant | coolant which flows in into the nozzle channel | path 13a is the refrigerant | coolant swirling in the turning space 30a, it has the speed component of a turning direction. On the other hand, in the present embodiment, the inner diameter of the portion of the nozzle body 32 that forms the minimum passage area portion 30m and the homogenizing portion 132 is larger than the outer diameter of the air column. The liquid-phase refrigerant is likely to come into contact with the portion (inner peripheral wall surface) that forms the conversion portion 132.

  Therefore, when the refrigerant having the velocity component in the swirling direction that has flowed into the nozzle passage 13a flows through the homogenizer 132, the velocity component in the swirl direction decreases due to friction between the inner wall surface of the homogenizer 132 and the liquid-phase refrigerant. To do. Of course, since the speed component in the turning direction is not completely eliminated by this friction, the refrigerant flowing through the nozzle passage 13a and the jet refrigerant injected from the nozzle passage 13a also have the speed component in the turning direction.

  Next, as shown in FIG. 2, the middle body 33 is provided with a rotating body-shaped through hole penetrating the front and back at the center, and driving the passage forming member 35 to be displaced to the outer peripheral side of the through hole. It is formed of a metal disk-like member that accommodates the means 37. The central axis of the through hole is arranged coaxially with the central axes of the swirling space 30a and the decompression space 30b. The middle body 33 is fixed inside the housing body 31 and below the nozzle body 32 by means such as press fitting.

  Between the upper surface of the middle body 33 and the inner wall surface of the housing body 31 facing the middle body 33, an inflow space 30c for retaining the refrigerant flowing in from the refrigerant suction port 31b is formed. In the present embodiment, since the tapered tip portion on the lower side of the nozzle body 32 is positioned inside the through hole of the middle body 33, the inflow space 30c is viewed from the central axis direction of the swirl space 30a and the decompression space 30b. The cross section is formed in an annular shape.

  The suction refrigerant inflow passage connecting the refrigerant suction port 31b and the inflow space 30c extends in the tangential direction of the inner peripheral wall surface of the inflow space 30c when viewed from the central axis direction of the inflow space 30c. Thus, in the present embodiment, the refrigerant that has flowed into the inflow space 30c from the refrigerant suction port 31b via the suction refrigerant inflow passage is swirled in the same direction as the refrigerant in the swirling space 30a.

  Further, in the range where the lower side of the nozzle body 32 is inserted, that is, in the range where the middle body 33 and the nozzle body 32 overlap when viewed from the radial direction perpendicular to the axis among the through holes of the middle body 33, the tapered tip of the nozzle body 32 is formed. The refrigerant passage area gradually decreases in the refrigerant flow direction so as to conform to the outer peripheral shape.

  Thus, a suction passage 30d is formed between the inner peripheral surface of the through hole and the outer peripheral surface on the lower side of the nozzle body 32 so as to communicate the inflow space 30c and the downstream side of the refrigerant flow in the decompression space 30b. That is, in this embodiment, the suction passage 13b that sucks the refrigerant from the outside is formed by the inflow space 30c and the suction passage 30d. Furthermore, the central axis vertical cross section of the suction passage 13b is also formed in an annular shape, and the suction refrigerant flows while swirling from the outer peripheral side to the inner peripheral side of the central shaft in the suction passage 13b.

  Further, in the through hole of the middle body 33, a pressure increasing space 30e formed in a substantially truncated cone shape gradually spreading in the refrigerant flow direction is formed on the downstream side of the refrigerant flow in the suction passage 30d. The pressurizing space 30e is a space in which the injection refrigerant injected from the nozzle passage 13a described above and the suction refrigerant sucked from the suction passage 30d are mixed to increase the pressure.

  Inside the pressure increasing space 30e, the lower side of the passage forming member 35 described above is disposed. Further, the expansion angle of the conical side surface of the passage forming member 35 in the pressure increasing space 30e is smaller than the expansion angle of the frustoconical space of the pressure increasing space 30e. The flow gradually expands toward the downstream side.

  In the present embodiment, the refrigerant passage formed between the inner peripheral surface of the middle body 33 forming the pressurizing space 30e and the outer peripheral surface on the lower side of the passage forming member 35 by expanding the refrigerant passage area in this manner. Is used as a diffuser passage 13c functioning as a diffuser, and the velocity energy of the mixed refrigerant of the injection refrigerant and the suction refrigerant is converted into pressure energy. That is, in the diffuser passage 13c, the injection refrigerant and the suction refrigerant are mixed and pressurized. Further, the cross-sectional shape perpendicular to the central axis of the diffuser passage 13c is also formed in an annular shape.

  Note that the refrigerant injected from the nozzle 13a toward the diffuser passage 13c and the refrigerant sucked from the suction passage 13b have a speed component in the swirling direction that swirls in the same direction as the refrigerant swirling in the swirling space 30a. . Therefore, the refrigerant flowing through the diffuser passage 13c and the refrigerant flowing out of the diffuser passage 13c have the same speed component in the turning direction.

  Next, the drive means 37 which is disposed inside the middle body 33 and displaces the passage forming member 35 will be described. The driving means 37 is configured to have a circular thin plate-like diaphragm 37a which is a pressure responsive member. More specifically, as shown in FIG. 2, the diaphragm 37a is fixed by means such as welding so as to partition a cylindrical space formed on the outer peripheral side of the middle body 33 into two upper and lower spaces.

  Of the two spaces partitioned by the diaphragm 37a, the space on the upper side (the inflow space 30c side) constitutes an enclosed space 37b in which a temperature-sensitive medium whose pressure changes according to the temperature of the refrigerant flowing out of the evaporator 14 is enclosed. Yes. A temperature sensitive medium having the same composition as the refrigerant circulating in the ejector refrigeration cycle 10 is enclosed in the enclosed space 37b so as to have a predetermined density. Therefore, the temperature sensitive medium in this embodiment is R134a.

  On the other hand, the lower space of the two spaces partitioned by the diaphragm 37a constitutes an introduction space 37c into which the refrigerant flowing out of the evaporator 14 is introduced via a communication path (not shown). Therefore, the temperature of the refrigerant flowing out of the evaporator 14 is transmitted to the temperature-sensitive medium enclosed in the enclosed space 37b through the lid member 37d and the diaphragm 37a that partition the inflow space 30c and the enclosed space 37b.

  Here, as is apparent from FIGS. 2 and 3, the suction passage 13 b is disposed on the upper side of the middle body 33 of the present embodiment, and the diffuser passage 13 c is disposed on the lower side of the middle body 33. Accordingly, at least a part of the driving means 37 is disposed at a position sandwiched from above and below by the suction passage 13b and the diffuser passage 13c when viewed from the radial direction of the axis.

  More specifically, the enclosed space 37b of the driving means 37 is a position where it overlaps with the suction passage 13b and the diffuser passage 13c when viewed from the central axis direction of the swivel space 30a, the passage forming member 35, etc. It arrange | positions in the position enclosed by the channel | path 13b for diffusers, and the diffuser channel | path 13c. As a result, the temperature of the refrigerant flowing out of the evaporator 14 is transmitted to the enclosed space 37b, and the internal pressure of the enclosed space 37b becomes a pressure corresponding to the temperature of the refrigerant flowing out of the evaporator 14.

  Further, the diaphragm 37a is deformed according to a differential pressure between the internal pressure of the enclosed space 37b and the pressure of the refrigerant flowing out of the evaporator 14 flowing into the introduction space 37c. For this reason, the diaphragm 37a is preferably formed of a tough material having high elasticity and good heat conduction, and is preferably formed of a thin metal plate such as stainless steel (SUS304).

  Further, the upper end side of a columnar actuating rod 37e is joined to the center portion of the diaphragm 37a by means such as welding, and the outer peripheral side of the lowermost side (bottom side) of the passage forming member 35 is joined to the lower end side of the actuating rod 37e. It is fixed. Thereby, the diaphragm 37a and the passage forming member 35 are connected, and the passage forming member 35 is displaced in accordance with the displacement of the diaphragm 37a, and the refrigerant passage area of the nozzle passage 13a (passage sectional area in the minimum passage area portion 30m) is adjusted. The

  Specifically, when the temperature (superheat degree) of the refrigerant flowing out of the evaporator 14 increases, the saturation pressure of the temperature-sensitive medium enclosed in the enclosed space 37b increases, and the pressure in the introduction space 37c is subtracted from the internal pressure of the enclosed space 37b. Increased differential pressure. Thereby, the diaphragm 37a displaces the channel | path formation member 35 in the direction (vertical direction lower side) which enlarges the channel | path cross-sectional area in the minimum channel | path area part 30m.

  On the other hand, when the temperature (superheat degree) of the refrigerant flowing out of the evaporator 14 is lowered, the saturation pressure of the temperature sensitive medium enclosed in the enclosed space 37b is lowered, and the difference obtained by subtracting the pressure of the introduction space 37c from the internal pressure of the enclosed space 37b. The pressure is reduced. Thereby, the diaphragm 37a displaces the passage forming member 35 in a direction (vertical direction upper side) in which the passage sectional area in the minimum passage area portion 30m is reduced.

  In this way, the diaphragm 37a displaces the passage forming member 35 in the vertical direction according to the superheat degree of the refrigerant flowing out of the evaporator 14, so that the superheat degree of the refrigerant flowing out of the evaporator 14 approaches a predetermined value. The passage sectional area in the minimum passage area portion 30m can be adjusted. The gap between the operating rod 37e and the middle body 33 is sealed by a sealing member such as an O-ring (not shown), and the refrigerant does not leak from the gap even if the operating rod 37e is displaced.

  Further, the bottom surface of the passage forming member 35 receives a load of a coil spring 40 fixed to the lower body 34. The coil spring 40 applies a load that urges the passage forming member 35 toward the side that reduces the cross-sectional area of the passage in the minimum passage area portion 30m (the upper side in FIG. 2). It is also possible to change the valve opening pressure of the passage forming member 35 to change the target degree of superheat.

  In the present embodiment, a plurality (specifically, two as shown in FIGS. 2 and 3) of columnar spaces are provided on the outer peripheral side of the middle body 33, and each of the circular thin plate-like shapes is provided inside the space. Although the diaphragm 37a is fixed and the two drive means 37 are comprised, the number of the drive means 37 is not limited to this. In addition, when providing the drive means 37 in multiple places, it is desirable to arrange | position at equal angle intervals with respect to a central axis, respectively.

  Alternatively, a diaphragm formed by an annular thin plate may be fixed in a space formed in an annular shape when viewed from the axial direction, and the diaphragm and the passage forming member 35 may be connected by a plurality of operating rods. Good.

  Next, the lower body 34 is formed of a cylindrical metal member, and is fixed in the housing body 31 by means such as screwing so as to close the bottom surface of the housing body 31. As shown in FIGS. 2 and 3, a gas-liquid separation space 30f is formed between the upper side of the lower body 34 and the middle body 33 to separate the gas and liquid refrigerant flowing out of the diffuser passage 13c. Yes.

  The gas-liquid separation space 30f is formed as a substantially cylindrical rotating body-shaped space, and the central axis of the gas-liquid separation space 30f is also the central axis of the swirl space 30a, the decompression space 30b, the passage forming member 35, and the like. And are arranged on the same axis.

  Further, as described above, the refrigerant flowing out of the diffuser passage 13c and flowing into the gas-liquid separation space 30f has a velocity component in the direction of turning in the same direction as the refrigerant swirling in the swirling space 30a. Therefore, the gas-liquid refrigerant is separated in the gas-liquid separation space 30f by the action of centrifugal force.

  At the center of the lower body 34, a cylindrical pipe 34a is provided coaxially with the gas-liquid separation space 30f and extending upward. And the liquid phase refrigerant | coolant isolate | separated in the gas-liquid separation space 30f is stored by the outer peripheral side of the pipe 34a. A gas-phase refrigerant outflow passage 34b is formed in the pipe 34a to guide the gas-phase refrigerant separated in the gas-liquid separation space 30f to the gas-phase refrigerant outlet 31d of the housing body 31.

  Further, the above-described coil spring 40 is fixed to the upper end portion of the pipe 34a. The coil spring 40 also functions as a vibration buffer member that attenuates the vibration of the passage forming member 35 caused by pressure pulsation when the refrigerant is depressurized. Further, an oil return hole 34c for returning the refrigeration oil in the liquid-phase refrigerant into the compressor 11 through the gas-phase refrigerant outflow passage 34b is formed in the root part (lowermost part) of the pipe 34a.

  As shown in FIG. 1, the inlet side of the evaporator 14 is connected to the liquid-phase refrigerant outlet 31 c of the ejector 13. The evaporator 14 performs heat exchange between the low-pressure refrigerant decompressed by the ejector 13 and the blown air blown into the vehicle interior from the blower fan 14a, thereby evaporating the low-pressure refrigerant and exerting an endothermic effect. It is a vessel.

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

  Next, a control device (not shown) includes a known microcomputer including a CPU, a ROM, a RAM, and the like and peripheral circuits thereof. This control device performs various calculations and processes based on the control program stored in the ROM, and controls the operations of the various electric actuators 11b, 12d, 14a and the like described above.

  In addition, the control device includes an internal air temperature sensor that detects the temperature inside the vehicle, an external air temperature sensor that detects the outside air temperature, a solar radiation sensor that detects the amount of solar radiation in the vehicle interior, and an air temperature (evaporator temperature) of the evaporator 14. A sensor group for air conditioning control such as an evaporator temperature sensor to detect, an outlet side temperature sensor to detect the temperature of the radiator 12 outlet side refrigerant, and an outlet side pressure sensor to detect the pressure of the radiator 12 outlet side refrigerant are connected, Detection values of these sensor groups are input.

  Furthermore, an operation panel (not shown) disposed near the instrument panel in the front part of the vehicle interior is connected to the input side of the control device, and operation signals from various operation switches provided on the operation panel are input to the control device. The As various operation switches provided on the operation panel, there are provided an air conditioning operation switch for requesting air conditioning in the vehicle interior, a vehicle interior temperature setting switch for setting the vehicle interior temperature, and the like.

  Note that the control device of the present embodiment is configured integrally with control means for controlling the operation of various control target devices connected to the output side of the control device. The configuration (hardware and software) for controlling the operation constitutes the control means of each control target device. For example, in this embodiment, the structure (hardware and software) which controls the action | operation of the electric motor 11b of the compressor 11 comprises the discharge capability control means.

  Next, the operation of the present embodiment in the above configuration will be described using the Mollier diagram of FIG. The vertical axis of the Mollier diagram shows pressures corresponding to P0, P1, and P2 in FIG. First, when the operation switch of the operation panel is turned on (ON), the control device operates the electric motor 11b, the cooling fan 12d, the blower fan 14a, and the like of the compressor 11. Thereby, the compressor 11 sucks the refrigerant, compresses it, and discharges it.

  The high-temperature and high-pressure gas-phase refrigerant discharged from the compressor 11 (point a5 in FIG. 5) flows into the condenser 12a of the radiator 12 and exchanges heat with the blown air (outside air) blown from the cooling fan 12d. , Dissipates heat and condenses. The refrigerant that has dissipated heat in the condensing unit 12a is gas-liquid separated in the receiver unit 12b. The liquid-phase refrigerant separated from the gas and liquid in the receiver unit 12b exchanges heat with the blown air blown from the cooling fan 12d in the supercooling unit 12c, and further dissipates heat to become a supercooled liquid-phase refrigerant (FIG. 5). a5 point → b5 point).

  The supercooled liquid-phase refrigerant that has flowed out of the supercooling portion 12c of the radiator 12 passes through the nozzle passage 13a formed between the inner peripheral surface of the decompression space 30b of the ejector 13 and the outer peripheral surface of the passage forming member 35. The pressure is reduced entropically and injected (b5 point → c5 point in FIG. 5). At this time, the refrigerant passage area in the minimum passage area 30m of the decompression space 30b is adjusted so that the superheat degree of the refrigerant on the outlet side of the evaporator 14 approaches a predetermined value.

  And the refrigerant | coolant which flowed out of the evaporator 14 is attracted | sucked through the refrigerant | coolant suction port 31b through the suction | inhalation channel | path 13b by the suction effect | action of the injection refrigerant | coolant injected from the nozzle channel | path 13a. Furthermore, the refrigerant injected from the nozzle passage 13a and the suction refrigerant sucked through the suction passage 13b and the like flow into the diffuser passage 13c (point c5 → d5 point, point h5 → d5 point in FIG. 5).

  In the diffuser passage 13c, the velocity energy of the refrigerant is converted into pressure energy by expanding the refrigerant passage area. As a result, the pressure of the mixed refrigerant rises while the injected refrigerant and the suction refrigerant are mixed (point d5 → point e5 in FIG. 5). The refrigerant flowing out of the diffuser passage 13c is gas-liquid separated in the gas-liquid separation space 30f (point e5 → f5, point e5 → g5 in FIG. 5).

  The liquid-phase refrigerant separated in the gas-liquid separation space 30f flows out from the liquid-phase refrigerant outlet 31c and flows into the evaporator 14. The refrigerant flowing into the evaporator 14 absorbs heat from the blown air blown by the blower fan 14a and evaporates, and the blown air is cooled (g5 point → h5 point in FIG. 5). On the other hand, the gas-phase refrigerant separated in the gas-liquid separation space 30f flows out of the gas-phase refrigerant outlet 31d, is sucked into the compressor 11, and is compressed again (point f5 → a5 in FIG. 5).

  The ejector refrigeration cycle 10 of the present embodiment operates as described above and can cool the blown air blown into the vehicle interior. Further, in the ejector refrigeration cycle 10, since the refrigerant whose pressure is increased in the diffuser passage 13c is sucked into the compressor 11, the driving power of the compressor 11 can be reduced and the cycle efficiency (COP) can be improved. .

  Further, according to the ejector 13 of the present embodiment, the refrigerant pressure on the turning center side of the swirling space 30a can be reduced to the pressure at which the refrigerant is boiled under reduced pressure by swirling the refrigerant in the swirling space 30a. Then, the refrigerant in the gas-liquid mixed state in which the gas-phase refrigerant and the liquid-phase refrigerant are mixed is decompressed in the nozzle passage 13a by flowing the refrigerant in the two-phase separated state on the turning center side of the turning space 30a into the nozzle passage 13a. be able to.

  Furthermore, since the homogenizing part 132 is formed in the nozzle passage 13a, the speed component in the swirling direction of the refrigerant can be reduced in the homogenizing part 132. As a result, the gas phase and the liquid phase are mixed homogeneously from the heterogeneous gas-liquid mixed state in which the gas phase refrigerant is unevenly distributed on the swivel center side and the liquid phase refrigerant is unevenly distributed on the outer peripheral side. The ideal gas-liquid mixed state can be obtained.

  Then, the refrigerant that has become an ideal gas-liquid mixed state in the homogenizing unit 132 is blocked (choked), and the flow rate of the refrigerant is accelerated until it reaches a supersonic state (a flow rate equal to or higher than the two-phase sonic speed). Furthermore, the supersonic state refrigerant can be accelerated by the divergent portion 31f.

  As a result, the flow velocity of the refrigerant injected from the nozzle passage 13a can be effectively increased, and the pressure energy of the refrigerant is converted into velocity energy in the nozzle passage 13a of the ejector that depressurizes the refrigerant in the gas-liquid mixed state. It is possible to prevent the energy conversion efficiency (corresponding to the nozzle efficiency of the prior art) from decreasing.

  Note that the ideal gas-liquid mixed state in which the gas phase and the liquid phase are homogeneously mixed is a liquid phase liquid droplet (liquid phase refrigerant particles) that is not unevenly distributed in a part of the nozzle passage 13a. It can be defined as a state of being homogeneously distributed in the phase refrigerant. Further, in an ideal gas-liquid mixed state in which the gas phase and the liquid phase are homogeneously mixed, the flow velocity of the droplets and the flow velocity of the vapor phase refrigerant are equal.

  This will be described in more detail with reference to FIG. FIG. 6 is a graph showing changes in the refrigerant passage area An in the nozzle passage 13a, changes in the wall surface pressure Pn of the refrigerant flowing through the nozzle passage 13a, and changes in the axial velocity Vn. Further, in FIG. 6, changes in the refrigerant passage area An, wall surface pressure Pn, and axial velocity Vn in the ejector of the present embodiment are indicated by thick solid lines, and the refrigerant passage area An, wall surface pressure Pn, and axial velocity Vn in the ejector of the prior application example are shown. This change is indicated by a thin broken line.

  Here, the wall surface pressure Pn shown in FIG. 6 is a static pressure on the outer peripheral side wall surface of the nozzle passage 13a, and the axial speed Vn is a speed that can be illustrated in the axial cross section of FIGS. This is the velocity component excluding the velocity component in the turning direction of the flow velocity. The refrigerant passage area An is a line segment perpendicular to the axial velocity Vn in the axial cross section, and is a line formed in a range from the outer peripheral surface of the passage forming member 35 to a portion where the decompression space 30b of the nozzle body 32 is formed. This is a value obtained from the shape formed when the minute is rotated around the central axis of the passage forming member 35.

  As shown in FIG. 6, the refrigerant that has flowed out of the swirling space 30 a flows into the tapered portion 131 of the nozzle passage 13 a, and the subsonic speed while decreasing the wall surface pressure Pn as the refrigerant passage area An in the tapered portion 131 decreases. Accelerate in the same state (flow velocity lower than the two-phase sound speed). As a result, the shaft speed Vn also increases.

  Further, the refrigerant accelerated in the subsonic state in the tapered portion 131 flows into the minimum passage area 30m. Here, the refrigerant flowing into the minimum passage area 30m is in a heterogeneous gas-liquid mixed state in which the gas-phase refrigerant is unevenly distributed on the swivel center side and the liquid-phase refrigerant is unevenly distributed on the outer peripheral side due to the centrifugal force of the swirl flow. Immediately after flowing into the minimum passage area 30m, it is in a subsonic speed state.

  For this reason, in the configuration in which the divergent portion 133 is disposed immediately after the minimum passage area portion 30m as in the ejector of the prior application example, the refrigerant passage area An of the divergent portion 133 is increased as shown by a thin broken line in FIG. Accordingly, the wall pressure Pn of the subsonic refrigerant increases and the axial speed Vn decreases. Thereafter, when the refrigerant is in an ideal gas-liquid mixed state and has a two-phase sound speed or higher (supersonic speed), the supersonic refrigerant is accelerated while lowering the wall pressure Pn.

  That is, in the configuration in which the divergent portion 133 is disposed immediately after the minimum passage area portion 30 m, the refrigerant is in a supersonic state inside the divergent portion 133. Therefore, in the refrigerant passage of the divergent portion 133, in the range from the minimum passage area portion 30m to the location where the refrigerant has a two-phase sound speed or higher, not only the supersonic refrigerant can be accelerated, but also the refrigerant passage area is increased. Will slow down the subsonic refrigerant.

  On the other hand, according to the ejector of this embodiment, since the homogenization part 132 is formed immediately after the minimum passage area part 30m, the liquid is unevenly distributed on the outer peripheral side (the inner peripheral wall surface side of the homogenization part 132). When the phase refrigerant rubs against the inner peripheral wall surface of the homogenizing unit 132, the speed component in the swirling direction of the refrigerant can be reduced.

  Thereby, the refrigerant in the homogenizing unit 132 can be brought close to an ideal gas-liquid mixed state, and the refrigerant can be blocked in the homogenizing unit 132, so that the refrigerant can be quickly brought into a supersonic state. Furthermore, since the refrigerant passage area An is formed constant in the homogenizer 132, the homogenizer 132 is less likely to cause an increase in wall pressure Pn and a reduction in the axial speed Vn due to the expansion of the refrigerant passage area An.

  Therefore, as shown by the thick solid line in FIG. 6, the refrigerant that has become supersonic in the homogenizing unit 132 can be caused to flow into the divergent portion 133, and the refrigerant can be accelerated immediately after flowing into the divergent portion 133. That is, according to the ejector 13 of the present embodiment, the entire region of the divergent portion 133 can be used for accelerating the refrigerant, and the energy conversion efficiency in the nozzle passage can be prevented from decreasing.

  Further, according to the ejector 13 of the present embodiment, the inner diameter of the portion of the nozzle body 32 that forms the minimum passage area portion 30m and the homogenizing portion 132 is larger than the outer diameter of the air column. Among them, the liquid refrigerant can be brought into contact with a portion (inner wall surface) where the homogenizing portion 132 is formed.

  Thereby, the velocity component in the swirling direction can be reduced by friction between the inner wall surface of the homogenizing unit 132 and the liquid phase refrigerant, and wall surface boiling due to friction between the inner wall surface of the homogenizing unit 132 and the liquid phase refrigerant is promoted. Can be made. Therefore, the refrigerant flowing into the homogenizing unit 132 can be quickly brought into an ideal gas-liquid mixed state.

  Further, according to the study by the present inventors, as described above, by setting the axial length L when the shape of the homogenizing portion 132 is converted to a cylindrical shape so as to satisfy the above formula F1, It has been found that the speed component in the swirl direction can be lowered until the inhomogeneous gas-liquid mixing state becomes a homogeneous gas-liquid mixing state, and that the refrigerant can be surely brought into a supersonic state in the homogenizing section 132. .

More specifically, the velocity component in the swirling direction until the gas-liquid refrigerant is unevenly distributed on the swivel center side and the non-homogeneous gas-liquid mixed state refrigerant in which the liquid-phase refrigerant is unevenly distributed on the outer peripheral side is brought to an ideal gas-liquid mixed state. The length L in the axial direction required to reduce the flow rate is the density ratio (ρ _L / ρ) of the density ρ _L of the liquid-phase refrigerant and the density ρ _g of the gas-phase refrigerant used as an index of the ease of boiling of the refrigerant. _It has been found that there is a correlation with _g ).

  Therefore, in the present embodiment, the minimum passage area that changes with the displacement of the passage forming member 35 and the minimum value (density ratio of carbon dioxide), the maximum value (density ratio of R600a) of the commonly used refrigerant density ratio. Based on the refrigerant passage area of the portion 30m, the range of the axial length L shown in the formula F1 is determined.

  Further, according to the ejector 13 of the present embodiment, since the drive means 37 is provided, the passage forming member 35 is displaced according to the load fluctuation of the ejector refrigeration cycle 10, and the refrigerant passage of the nozzle passage 13a and the diffuser passage 13c. The area can be adjusted. Therefore, the ejector 13 can be appropriately operated in accordance with the load fluctuation of the ejector refrigeration cycle 10.

  Furthermore, since the enclosed space 37b in which the temperature sensitive medium is enclosed in the driving means 37 is disposed between the suction passage 13b and the diffuser passage 13c, the space between the suction passage 13b and the diffuser passage 13c is disposed. The space formed can be effectively used. Therefore, the enlargement of the physique as the whole ejector can be suppressed.

  Moreover, since the enclosed space 37b is disposed at a position surrounded by the suction passage 13b and the diffuser passage 13c, the temperature of the refrigerant flowing out of the evaporator 14 flowing through the suction passage 13b without being affected by the outside air temperature or the like. Can be satisfactorily transmitted to the temperature sensitive medium, and the pressure in the enclosed space 37b can be changed. That is, the pressure in the enclosed space 37b can be accurately changed according to the temperature of the refrigerant flowing out of the evaporator 14.

  Further, since the body 30 of the ejector 13 of the present embodiment is formed with a gas-liquid separation space 30f for separating the gas-liquid of the refrigerant flowing out from the diffuser passage 13c, a gas-liquid separation means is provided separately from the ejector 13. In contrast, the volume of the gas-liquid separation space 30f can be effectively reduced.

  In other words, in the gas-liquid separation space 30f of the present embodiment, the refrigerant flowing out of the diffuser passage 13c formed in an annular cross section already has a velocity component in the direction of swirling, so that the refrigerant flows in the gas-liquid separation space 30f. It is not necessary to provide a space for generating a swirling flow. Therefore, the volume of the gas-liquid separation space 30f can be effectively reduced as compared with the case where the gas-liquid separation means is provided separately from the ejector 13.

(Second Embodiment)
In the present embodiment, as shown in the schematic enlarged cross-sectional view of FIG. 7, the shape of the portion (inner peripheral wall surface) where the homogenizing portion 132 is formed in the nozzle body 32, and the passage formation, as compared with the first embodiment. The shape of the member 35 is changed. More specifically, in the present embodiment, a portion of the nozzle body 32 that forms the homogenizing portion 132 extends in the axial direction of the passage forming member 35. In other words, the homogenization part 132 of this embodiment is formed in a substantially cylindrical shape.

  Other configurations and operations of the ejector refrigeration cycle 10 are the same as those in the first embodiment. Therefore, also in the ejector 13 of the present embodiment, as in the first embodiment, the energy conversion efficiency when the pressure energy of the refrigerant is converted into velocity energy in the nozzle passage 13a of the ejector that depressurizes the refrigerant in the gas-liquid mixed state. It can be suppressed that (equivalent to the nozzle efficiency of the prior art) decreases.

  Furthermore, in the homogenizing part 132 of the present embodiment, the refrigerant passage does not expand in the radial direction of the passage forming member 35, so that the friction between the inner wall surface of the homogenizing part 132 and the liquid phase refrigerant is promoted, and the homogenizing part 132. It is possible to make the refrigerant flowing into the gas-liquid mixed state more quickly. In other words, the axial length L of the homogenizing part 132 can be shortened.

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

  (1) In the above-described embodiment, the example in which the refrigerant passage area is uniformly formed from the minimum passage area portion 30 m toward the downstream side of the refrigerant flow has been described as the homogenization portion 132. The shape of 132 is not limited to this. For example, the homogenizer 132 may be formed in a shape in which the refrigerant passage area gradually increases from the minimum passage area portion 30m toward the downstream side of the refrigerant flow.

  In this case, the degree of expansion of the refrigerant passage area of the homogenization unit 132 is the refrigerant of the divergent portion 133 in order to prevent the subsonic refrigerant from decelerating due to the expansion of the refrigerant passage area in the homogenization unit 132. What is necessary is just to set smaller than the expansion degree of a passage area.

According to the adjustment by the present inventor, as shown in FIG. 8, the shape of the homogenizing portion 132 is converted into a truncated cone shape whose upper surface is equivalent to the refrigerant passage area of the smallest passage area portion 30m. It has been found that the expansion angle θ should be set so as to satisfy the following formula F2 when the expansion angle in the axial section is θ.
0 <θ ≦ 0.5 ° (F2)
Note that, as shown in the above formula F2, since it is desirable that the spread angle θ is determined to be a relatively small value, the homogenizing unit 132 has a truncated cone shape that is extremely close to a cylindrical shape. Therefore, the axial length L and the equivalent diameter D may be set so as to satisfy the above-described formula F1.

  (2) In the above embodiment, the refrigerant passage formed in the range where the line segment extending in the normal direction from the outer peripheral surface of the passage forming member 35 intersects the inner peripheral surface of the pressure reducing space 30b of the nozzle body 32 is defined as the nozzle passage 13a. However, conversely, a refrigerant passage formed in a range where a line segment extending in the normal direction from the inner peripheral surface of the decompression space 30b intersects the outer peripheral surface of the passage forming member 35 may be used as the nozzle passage 13a.

  Further, in the above-described embodiment, the refrigerant passage area An is obtained from the shape formed when the line segment perpendicular to the axial velocity Vn in the axial section is rotated around the central axis of the passage forming member 35. Although the example which employ | adopted the value was demonstrated, the value of refrigerant passage area An is not limited to this.

  For example, as the refrigerant passage area An, a line segment formed approximately in a range extending in a normal direction from the outer peripheral surface of the passage forming member 35 and intersecting with a portion forming the pressure reducing space 30b of the nozzle body 32 is formed as a passage. You may employ | adopt the value calculated | required from the shape formed when it rotates around the central axis of the member 35. FIG.

  Furthermore, as a refrigerant passage area An, approximately, a line segment formed in a range that extends in a radial direction or an axial direction from the outer peripheral surface of the passage forming member 35 and intersects with a portion that forms the pressure reducing space 30b of the nozzle body 32, You may employ | adopt the value calculated | required from the donut shape formed when it rotates around the central axis of the channel | path formation member 35, or a cylindrical side surface shape.

  (3) In the first embodiment described above, as the drive means 37 for displacing the passage forming member 35, the enclosed space 37b in which the temperature sensitive medium that changes in pressure with temperature change is enclosed, and the temperature sensitive medium in the enclosed space 37b Although the example which employ | adopted what was comprised with the diaphragm 37a displaced according to the pressure of this was demonstrated, a drive means is not limited to this.

  For example, a thermowax that changes in volume depending on temperature may be employed as the temperature-sensitive medium, or a structure having a shape memory alloy elastic member as the driving means may be employed. Further, a drive unit that displaces the passage forming member 35 by an electric motor may be employed.

  (4) Although the details of the liquid-phase refrigerant outlet of the liquid-phase refrigerant outlet 31c of the ejector 13 are not described in the above-described embodiment, decompression means (for example, an orifice or A side fixed throttle made of a capillary tube) may be arranged.

  (5) In the above-described embodiment, the example in which the ejector refrigeration cycle 10 including the ejector 13 of the present invention is applied to a vehicle air conditioner has been described. However, the application of the ejector refrigeration cycle 10 including the ejector 13 of the present invention is described. Is not limited to this. For example, the present invention may be applied to a stationary air conditioner, a cold storage container, a cooling / heating device for a vending machine, and the like.

  (6) In the above-described embodiment, an example in which a subcool type heat exchanger is employed as the radiator 12 has been described. However, an ordinary radiator including only the condensing unit 12a may be employed. In the above-described embodiment, the example in which the constituent members such as the body 30 of the ejector 13 are formed of metal has been described. However, the material is not limited as long as the functions of the respective constituent members can be exhibited. Therefore, you may form these structural members with resin.

DESCRIPTION OF SYMBOLS 10 Ejector-type refrigeration cycle 13 Ejector 13a Nozzle passage 13b Suction passage 13c Diffuser passage 30 Body 30m Minimum passage area portion 35 Passage formation member 131 Pointer 132 Homogenization portion 133 Wide end portion

Claims (7)

An ejector applied to a vapor compression refrigeration cycle apparatus (10),
A swirling space (30a) for swirling the refrigerant flowing in from the refrigerant inlet (31a), a decompression space (30b) for decompressing the refrigerant flowing out of the swirling space (30a), and a refrigerant flow downstream of the decompression space (30b) The suction passage (13b) that communicates with the outside and sucks the refrigerant from the outside, and the pressure rising that mixes the injection refrigerant injected from the decompression space (30b) and the suction refrigerant sucked from the suction passage (13b) A body (30) in which a space (30e) is formed;
At least a portion is disposed in the decompression space (30b) and in the pressurization space (30e), and is formed in a conical shape whose cross-sectional area increases with distance from the decompression space (30b). A passage forming member (35) formed,
The refrigerant passage formed between the inner peripheral surface of the body (30) forming the decompression space (30b) and the outer peripheral surface of the passage forming member (35) is the swirling space (30a). A nozzle passage (13a) that functions as a nozzle for depressurizing and injecting the refrigerant flowing out from
The refrigerant passage formed between the inner peripheral surface of the body (30) forming the pressurizing space (30e) and the outer peripheral surface of the passage forming member (35) is the injection refrigerant and the suction A diffuser passage (13c) that functions as a diffuser for mixing and increasing the pressure of the refrigerant;
Furthermore, the nozzle passage (13a) has a minimum passage area portion (30m) having the smallest refrigerant passage area, and is disposed downstream of the refrigerant flow in the minimum passage area portion (30m) and is a velocity component in the swirling direction of the refrigerant. And a divergent portion (133) in which the refrigerant passage area gradually increases from the outlet side of the homogenizing portion (132) toward the downstream side of the refrigerant flow. And ejector.   An inner diameter of a portion of the body (30) that forms the minimum passage area (30m) is outside of a gas phase refrigerant that is unevenly distributed in a columnar shape on the turning center side when the refrigerant swirls in the swirling space (30a). The ejector according to claim 1, wherein the ejector is formed larger than the diameter.   The inner peripheral wall surface of a part of the body (30) that forms the homogenizing part (132) extends in the axial direction of the passage forming member (35). Ejector.   The said homogenization part (132) is formed in the refrigerant | coolant passage area uniformly from the said minimum channel | path area part (30m) toward a refrigerant | coolant flow downstream, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Ejector as described in. The homogenization part (132) is formed in a shape in which the refrigerant passage area gradually increases from the minimum passage area part (30m) toward the refrigerant flow downstream side,
The degree of expansion of the refrigerant passage area of the homogenization part (132) is smaller than the degree of expansion of the refrigerant passage area of the divergent part (133), according to any one of claims 1 to 3. Ejector. The shape of the homogenizing portion (132) is converted into a truncated cone shape whose upper surface is equivalent to the refrigerant passage area of the minimum passage area portion (30 m), and the spread angle in the axial cross section of the truncated cone shape is defined as θ. sometimes,
0 <θ ≦ 0.5 °
The ejector according to claim 5, wherein: The shape of the homogenizing part (132) is the same as that of the refrigerant passage area of the minimum passage area part (30m) or the upper surface and the bottom face of the cylindrical passage or the upper face is equivalent to the refrigerant passage area of the minimum passage area part (30m). The axial length of the columnar shape or the truncated cone shape when converted into a truncated cone shape is L,
When the equivalent diameter of the refrigerant passage area in the minimum passage area portion (30 m) is D,
0.1 ≦ L / D ≦ 6
The ejector according to claim 1, wherein the ejector is configured as follows.

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