JP3941646B2 - Ejector type decompression device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vapor compression refrigerator (ejector) using an ejector (see JIS Z 8126 number 2.1.2.3) that is a momentum transport pump that transports fluid by the entrainment action of a working fluid ejected at high speed. Cycle).
[0002]
[Prior art and problems to be solved by the invention]
As is well known, the ejector cycle circulates the low-pressure side refrigerant, that is, the refrigerant in the evaporator, by the pump action of the ejector, and converts the dynamic pressure to static pressure at the boosting part in the ejector to suck the compressor suction pressure. However, if the energy conversion efficiency of the ejector, that is, the ejector efficiency is reduced, the suction pressure cannot be sufficiently increased by the ejector, and the compressor power consumption is reduced. Cannot be sufficiently reduced, and a sufficient amount of refrigerant cannot be circulated through the evaporator.
[0003]
In view of the above, the present invention firstly provides a novel ejector-type decompression device different from the conventional one, and secondly, it is an object to improve ejector efficiency.
[0004]
In order to achieve the above object, according to the present invention, in the invention described in claim 1, a radiator (20) for cooling a high-temperature and high-pressure refrigerant compressed by a compressor (10), and a low-temperature and low-pressure reduced. This is an ejector-type decompression device that is applied to a vapor compression refrigerator that has an evaporator (30) that evaporates the refrigerant and moves the low-temperature side heat to the high-temperature side, and flows out from the radiator (20) The pressure energy of the refrigerant is converted into velocity energy to decompress and expand the refrigerant, and the throat portion (41a) where the passage cross-sectional area is reduced most in the middle of the passage, and the divergent portion (41b) where the passage cross-sectional area increases toward the downstream side. The Laval type nozzle (41) having a) and the refrigerant injected from the nozzle (41) and the refrigerant sucked from the evaporator (30) are mixed while the velocity energy is converted to pressure energy to increase the refrigerant pressure. Higher speeds to cause a step-up portion (42, 43), the change ratio of the cross-sectional area of the divergent portion (41b) is formed in a substantially constant boosting unit (42, 43) is injected from the nozzle (41) The refrigerant flowing from the nozzle (41) and the mixing part (42) for mixing the gas-phase refrigerant with the gas-phase refrigerant mixed while sucking the gas-phase refrigerant evaporated in the evaporator (30) by the refrigerant flow, and the nozzle (41) The refrigerant (43) has a diffuser (43) whose passage sectional area increases toward the downstream side, and the rate of change of the passage sectional area of the diffuser (43) is substantially constant. The inner wall that is formed and forms a passage in the nozzle (41) is formed of a smooth curved surface having no corners, and the refrigerant passage from the mixing portion (42) to the outlet of the diffuser (43) has a corner portion. No smooth curved surface Made is characterized in that is.
[0005]
As a result, the refrigerant can flow smoothly while suppressing the occurrence of loss such as vortex loss in the passage in the nozzle (41), so that the ejector efficiency can be improved and the new ejector different from the conventional one can be obtained. A pressure reducing device of the type can be obtained.
[0007]
Furthermore, since the rate of change of the passage cross-sectional area of the divergent portion (41b) is formed to be substantially constant , the refrigerant can flow smoothly while suppressing loss due to sudden expansion in the divergent portion (41b). It is possible to improve the ejector efficiency.
[0009]
Furthermore, the refrigerant path from the mixing section (42) to the outlet of the diffuser (43) is formed of a smooth curved surface without corners, so that the refrigerant from the mixing section (42) to the outlet of the diffuser (43) is obtained. The refrigerant can flow smoothly while suppressing the occurrence of loss such as vortex loss in the passage, and the ejector efficiency can be improved.
[0011]
Further, by changing ratio of the cross-sectional area of the diffuser (43) is formed in a substantially constant, Ru can flow a coolant smoothly while suppressing the loss due to rapid expansion occurs in the diffuser (43) Therefore, the ejector efficiency can be improved.
[0012]
The invention according to claim 2 is characterized in that the outer wall surface (41c) of the nozzle (41) is formed in a curved shape that is depressed toward the refrigerant passage inside.
[0013]
Thereby, the collision angle of the suction flow sucked from the evaporator (30) and the driving flow blown from the nozzle (41) can be reduced, and both can be brought into contact in a substantially parallel state. Therefore, the suction flow and the driving flow can be smoothly mixed while suppressing the occurrence of collision loss, so that the ejector efficiency can be improved.
The invention according to claim 3 includes a radiator (20) for cooling the high-temperature and high-pressure refrigerant compressed by the compressor (10) and an evaporator (30) for evaporating the decompressed low-temperature and low-pressure refrigerant. An ejector-type decompression device applied to a vapor compression refrigerator that moves low-temperature heat to a high-temperature side, converting the pressure energy of the refrigerant flowing out of the radiator (20) into velocity energy and A Laval nozzle (41) having a throat portion (41a) whose passage cross-sectional area is reduced most in the middle of the passage and a divergent portion (41b) whose passage cross-sectional area increases toward the downstream side, A pressure increasing unit (42, 43) for increasing the pressure of the refrigerant by converting the velocity energy into pressure energy while mixing the refrigerant injected from the nozzle (41) and the refrigerant sucked from the evaporator (30); The inner wall forming the passage in the nozzle (41) has a smooth curved surface with no corners, and the outer wall surface (41c) of the nozzle (41) is recessed toward the refrigerant passage inside. It is formed in a curved surface shape.
According to this, similarly to the ejector-type decompression device according to the first aspect, the refrigerant can flow smoothly in the passage in the nozzle (41), so that the ejector efficiency can be improved. Further, similarly to the ejector-type decompression device according to the second aspect, the suction flow and the drive flow can be smoothly mixed to improve the ejector efficiency.
[0014]
Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
In the present embodiment, the ejector according to the present invention is applied to an ejector cycle for a vehicle air conditioner, and FIG. 1 is a schematic diagram of an ejector cycle 1 using CFC (134a) or carbon dioxide as a refrigerant. FIG. 3 is a schematic diagram of the ejector 40, and FIG. 3 is a ph diagram showing the overall macro operation of the ejector cycle.
[0016]
The compressor 10 is a well-known variable capacity compressor that obtains power from the traveling engine and sucks and compresses the refrigerant. The radiator 20 exchanges heat between the refrigerant discharged from the compressor 10 and the outdoor air to obtain the refrigerant. A high-pressure side heat exchanger for cooling.
[0017]
The evaporator 30 is a low-pressure side heat exchanger that cools the air blown into the room by evaporating the liquid phase refrigerant by evaporating the liquid phase refrigerant by exchanging heat between the air blown into the room and the liquid phase refrigerant.
[0018]
The ejector 40 expands the refrigerant under reduced pressure and sucks the gas-phase refrigerant evaporated in the evaporator 30 and converts the expansion energy into pressure energy to increase the suction pressure of the compressor 10.
[0019]
As shown in FIG. 2, the ejector 40 converts the pressure energy of the inflowing high-pressure refrigerant into velocity energy to cause the refrigerant to be isentropically decompressed and expanded, and a high-speed refrigerant flow ejected from the nozzle 41. While sucking the gas-phase refrigerant evaporated in the evaporator 30, the mixing unit 42 that mixes the refrigerant flow ejected from the nozzle 41 and the refrigerant ejected from the nozzle 41 and the refrigerant sucked from the evaporator 30 are mixed. It comprises a diffuser 43 or the like that converts velocity energy into pressure energy to increase the pressure of the refrigerant.
[0020]
At this time, in the mixing unit 42, the driving flow and the suction flow are mixed so that the sum of the momentum of the driving flow ejected from the nozzle 41 and the momentum of the suction flow sucked from the evaporator 30 is preserved. Also in the mixing part 42, the refrigerant pressure (static pressure) increases.
[0021]
On the other hand, in the diffuser 43, the velocity energy (dynamic pressure) of the refrigerant is converted into pressure energy (static pressure) by gradually increasing the cross-sectional area of the passage, so that in the ejector 40, the mixing section 42 and the diffuser 43 Both increase the refrigerant pressure. Therefore, hereinafter, the mixing unit 42 and the diffuser 43 are collectively referred to as a boosting unit.
[0022]
And in order to accelerate the speed of the refrigerant | coolant ejected from the nozzle 41 to a sound speed or more, the Laval nozzle (refer to fluid engineering (The University of Tokyo Press)) which has the throat part 41a in which the passage area was reduced most in the way is adopted. .
[0023]
Further, the inner wall forming the passage in the nozzle 41 is configured by a smooth curved surface having no corners. In particular, the divergent portion 41b has a substantially constant passage cross-sectional area change rate with respect to the refrigerant flow direction. Is set to
[0024]
Similarly, the refrigerant passage extending from the mixing portion 42 to the outlet of the diffuser 43 is also configured with a smooth curved surface having no corners, and the diffuser 43 has a change rate of the passage cross-sectional area substantially constant and goes toward the downstream side. It is expanding.
[0025]
Further, the outer wall surface 41c of the nozzle 41 is formed in a curved shape that is recessed toward the internal refrigerant passage.
[0026]
In FIG. 1, the gas-liquid separator 50 is gas-liquid separation means for storing the refrigerant by flowing the refrigerant flowing out from the ejector 40 and separating the flowing refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant, The gas-phase separator outlet of the gas-liquid separator 50 is connected to the suction side of the compressor 10, and the liquid-phase refrigerant outlet is connected to the inlet side of the evaporator 30 side. The throttle 60 is a decompression unit that decompresses the liquid-phase refrigerant flowing out of the gas-liquid separator 50.
[0027]
And in this embodiment, as shown in FIG. 3, the high pressure refrigerant | coolant which flows in into the nozzle 41 with the compressor 10 is pressure | voltage-risen more than the critical pressure of a refrigerant | coolant. Incidentally, the symbol indicated by ● in FIG. 3 indicates the state of the refrigerant at the symbol position indicated by ● in FIG.
[0028]
Next, a manufacturing method and characteristics of the ejector 40 will be described.
[0029]
1. Method for Manufacturing Nozzle 41 In the present embodiment, a metal (for example, stainless steel) powder is filled into a mold, the shape of nozzle 41 is compression-molded, and then sintered at a high temperature or high pressure. The nozzle 41 is manufactured, and the hardness of the nozzle 41 is increased by setting the filling rate when the powder is filled in the mold to 96% or more.
[0030]
Incidentally, a normal sintered metal has a filling rate of about 80%. If the nozzle 41 is manufactured at a filling rate of 80%, the hardness is small, and the throat 41a and the subsequent parts may be eroded by cavitation generated in the throat 41a. is high, in the present embodiment, since the filling rate of 96% or more, it is possible to prevent subsequent throat 41a is corrupted diet (erosion) by cavitation.
[0031]
2. Method for Manufacturing Booster In this embodiment, the booster is manufactured by subjecting a metal (for example, stainless steel) tube material to plastic working. Examples of the plastic working method include swaging, pressing, spinning, and spatula drawing (see JIS B 0122).
[0032]
Next, the general operation of the ejector cycle will be described (see FIG. 3).
[0033]
The refrigerant discharged from the compressor 10 is circulated to the radiator 20 side. As a result, the refrigerant cooled by the radiator 20 is isentropically decompressed and expanded at the nozzle 41 of the ejector 40 and flows into the mixing unit 42 at a speed equal to or higher than the speed of sound.
[0034]
Then, since the refrigerant evaporated in the evaporator 30 is sucked into the mixing unit 42 by the pumping action accompanying the entrainment action of the high-speed refrigerant flowing into the mixing unit 42, the low-pressure side refrigerant is reduced to the gas-liquid separator 50 → throttle. It circulates in order of 60-> evaporator 30-> ejector 40 (pressure | voltage riser)-> gas-liquid separator 50.
[0035]
On the other hand, the refrigerant sucked from the evaporator 30 (suction flow) and the refrigerant blown out from the nozzle 41 (driving flow) are mixed by the mixing unit 42 and the dynamic pressure thereof is converted into static pressure by the diffuser 43. Return to the liquid separator 50.
[0036]
Next, the effect of this embodiment is described.
[0037]
In the present embodiment, the inner wall forming the passage in the nozzle 41 is configured with a smooth curved surface having no corners. Therefore, the inner wall is smooth while suppressing the occurrence of loss such as vortex loss in the passage in the nozzle 41. Thus, the refrigerant can be flowed through, and the ejector efficiency can be improved.
[0038]
Further, since the divergent portion 41b is set so that the passage cross-sectional area change rate with respect to the refrigerant flow direction is substantially constant, the refrigerant can be smoothly supplied while suppressing loss due to sudden expansion in the divergent portion 41b. The ejector efficiency can be improved.
[0039]
Moreover, since the refrigerant path from the mixing part 42 to the outlet of the diffuser 43 is also formed with a smooth curved surface without corners, losses such as vortex loss occur in the refrigerant path from the mixing part 42 to the outlet of the diffuser 43. Accordingly, it is possible to smoothly flow the refrigerant while suppressing this, and it is possible to improve the ejector efficiency.
[0040]
Further, since the diffuser 43 is enlarged toward the downstream side with the change rate of the passage cross-sectional area being substantially constant, the refrigerant can flow smoothly while suppressing the loss caused by the sudden expansion in the diffuser 43. The ejector efficiency can be improved.
[0041]
Furthermore, since the outer wall surface 41c of the nozzle 41 is formed in a curved shape that sinks toward the internal refrigerant passage side, as shown in FIG. 4, the collision angle between the suction flow and the drive flow is reduced and both Can be brought into contact in a substantially parallel state. Therefore, the suction flow and the driving flow can be smoothly mixed while suppressing the occurrence of collision loss, so that the ejector efficiency can be improved.
[0042]
(Other embodiments)
In the above-described embodiment, the present invention is applied to the vehicle air conditioner, but the application of the present invention is not limited to this.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an ejector cycle according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of an ejector according to an embodiment of the present invention.
FIG. 3 is a ph diagram.
FIG. 4 is an explanatory diagram of an ejector according to an embodiment of the present invention.
[Explanation of symbols]
40 ... ejector, 41 ... nozzle, 41a ... throat part, 41b ... divergent part,
42: mixing unit, 43 ... diffuser.

Claims (3)

It has a radiator (20) that cools the high-temperature and high-pressure refrigerant compressed by the compressor (10), and an evaporator (30) that evaporates the low-temperature and low-pressure refrigerant that has been decompressed. An ejector-type decompression device applied to a vapor compression refrigerator that is moved to
The pressure energy of the refrigerant flowing out of the radiator (20) is converted into velocity energy to decompress and expand the refrigerant, and the throat portion (41a) having the smallest passage cross-sectional area in the middle of the passage, and the passage toward the downstream side. A Laval nozzle (41) having a divergent portion (41b) with an enlarged cross-sectional area;
And a refrigerant between the evaporator (30) the velocity energy while mixing the sucked refrigerant is converted into pressure energy from the boosting section for boosting the pressure of the refrigerant injected (42, 43) from the nozzle (41) ,
The rate of change of the cross-sectional area of the divergent portion (41b) is formed to be substantially constant,
The said pressure | voltage rise part (42, 43) is injected from the said nozzle (41), attracting | sucking the gaseous-phase refrigerant | coolant which evaporated by the said evaporator (30) with the high-speed refrigerant | coolant flow injected from the said nozzle (41). The mixing section (42) that mixes the refrigerant and the gas-phase refrigerant, and the pressure of the refrigerant injected from the nozzle (41) and the gas-phase refrigerant are increased while being mixed, and the passage cross-sectional area increases toward the downstream side. A diffuser (43)
The rate of change of the cross-sectional area of the diffuser (43) is formed substantially constant,
An inner wall forming a passage in said nozzle (41) is constituted by a smooth curved surface corners without further refrigerant passage leading to the outlet of the diffuser (43) from the mixing unit (42), corner portions An ejector-type decompression device characterized by comprising a smooth curved surface . 2. The ejector-type decompression device according to claim 1 , wherein the outer wall surface (41 c) of the nozzle (41) is formed in a curved shape that is recessed toward the internal refrigerant passage. It has a radiator (20) that cools the high-temperature and high-pressure refrigerant compressed by the compressor (10), and an evaporator (30) that evaporates the decompressed low-temperature and low-pressure refrigerant. An ejector-type decompression device applied to a vapor compression refrigerator that is moved to
  The pressure energy of the refrigerant flowing out of the radiator (20) is converted into velocity energy to decompress and expand the refrigerant, and the throat portion (41a) whose passage cross-sectional area is reduced in the middle of the passage and the passage toward the downstream side. A Laval nozzle (41) having a divergent portion (41b) with an enlarged cross-sectional area;
A pressure increasing section (42, 43) for increasing the pressure of the refrigerant by converting the velocity energy into pressure energy while mixing the refrigerant injected from the nozzle (41) and the refrigerant sucked from the evaporator (30); ,
  The inner wall forming the passage in the nozzle (41) is composed of a smooth curved surface without corners,
  Further, the outer wall surface (41c) of the nozzle (41) is formed in a curved surface shape so as to sink into the internal refrigerant passage side.

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