JPH1137577A - Nozzle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a cooling performance a freezing cycle provided with an ejector by a method wherein a nozzle effect is further improved while an increasing of an entire length of a nozzle main body assembled in the ejector is restricted to be a minimum value. SOLUTION: Throttle sections 17, 18 are arranged in the midway part of a refrigerant passage 15. A refrigerant passage 15 of a nozzle main body 12 is formed in such a way that a second spread angle θ2 of a passage wall surface of a fourth passage 24 ranging from a fluid peeling-off portion 19 to an injection port 20 is made smaller than a first spread angle θ1 at a passage wall surface of a third passage 23 ranging form the throttle section 18 to a fluid peeling-off section 19. With such as arrangement as above, the occurrence of peeling-off state of gas-liquid double-phase refrigerant from the passage wall surface within the fourth passage 24 and well as the occurrence of eddy flow is restricted, thereby making it possible to restrict reduction in pressure in respect to a uniform flow model without reducing a spread angle of entire region of the refrigerant passage 15 at a downstream side of the throttle section 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle device used as, for example, an ejector of a refrigeration cycle.

[0002]

2. Description of the Related Art Heretofore, as a means for improving the efficiency of a refrigeration cycle of a vehicle air conditioner, for example, a refrigerant condenser and a gas-liquid separator of a refrigeration cycle have been used in order to increase the circulation flow rate of the refrigerant circulating in a refrigerant evaporator. And an ejector is connected between them. In order to further improve the performance of the refrigeration cycle, it is essential to increase the efficiency of the ejector. Here, as a technique for improving the nozzle efficiency in order to increase the efficiency of the ejector, there is a technique described in Japanese Patent Application Laid-Open No. 5-149652.

[0003] As shown in FIG. 3A, this conventional technique uses a nozzle body 10 incorporated in an ejector body.
The two throttle portions 102, 10 on the upstream side of the
3 to make the refrigerant flowing into the gas-liquid two-phase flow state,
Further, the inside diameter of the fluid passage between the throttle portions 102 and 103 is enlarged, and the two-phase flow is re-condensed while leaving fine bubbles, thereby making it easy to boil in the next fluid passage. Thereby, the circulating flow of the refrigerant in the fluid passage from the throttle unit 103 to the ejection port 101 is made closer to a homogeneous flow by atomizing the droplets to reduce the difference in gas-liquid velocity, thereby improving the nozzle efficiency. I have to.

[0004]

However, in the prior art, there is a problem that the nozzle efficiency is about 80%, which is lower than the practically used efficiency of about 90%. The main cause of this is that, when the divergence angle of the inner wall surface of the fluid passage is a constant angle θ0 from the restricting portion 103 to the ejection port 101, the homogeneous flow model shown by the broken line in FIG. As can be seen from the rapid decrease in the pressure at the nozzle, it is assumed that a large separation occurred in the middle of the fluid passage from the throttle portion 103 to the ejection port 101, and that a vortex was generated on the inner wall surface of the fluid passage. Is done. Here, a mark in FIG. 3B represents the first conventional example A, and shows a case where the suction flow rate (Ge) sucked by the suction portion of the ejector is 0. 3 (b) indicates the second conventional example B,
The case where the suction flow rate (Ge) is suctioned by the suction unit of the ejector and is the maximum value is shown.

[0005] For this reason, in the prior art, there is a problem that the pressure drop of the refrigerant in the fluid passage is not well converted to velocity energy, and does not reach a nozzle efficiency of about 90% which is practically used. . To solve this problem, it is conceivable to reduce the spread angle of the fluid passage in the entire region. However, in the fluid passage, the passage length from the throttle portion 103 to the separated portion where the coolant is separated is increased. This allows
Since the dimension of the nozzle body 100 in the cylinder direction becomes longer, there is a problem that the ejector body becomes larger.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a nozzle device capable of obtaining a practical nozzle efficiency by further improving the nozzle efficiency while minimizing the increase in the size of the nozzle body in the cylinder direction. Is to do.

[0007]

According to the first aspect of the present invention, the fluid separation is made larger than the first spread angle of the passage wall surface of the fluid passage from the throttle portion to the fluid separation portion where the separation phenomenon of the fluid occurs. By reducing the second divergence angle of the passage wall surface of the fluid passage from the portion to the jet outlet, the separation of the fluid from the passage wall surface in the fluid passage and the generation of the vortex flow can be suppressed, and the pressure drop against the homogeneous flow can be suppressed. it can. Thereby, almost all the pressure drop of the fluid in the fluid passage can be converted into velocity energy. Further, the nozzle efficiency can be further improved without reducing the divergence angle of the entire area of the fluid passage from the throttle section to the ejection port. Therefore, it is possible to obtain practical nozzle efficiency while minimizing the increase in the dimension of the nozzle body in the cylinder direction.

According to the second aspect of the present invention,
By making the second spread angle a constant angle from the fluid separation portion to the jet port, it becomes easy to manufacture the nozzle body.
According to the third aspect of the present invention, by changing the second spread angle so as to follow the pressure change of the homogeneous flow,
Nozzle efficiency can be further improved with the minimum necessary dimension of the nozzle body in the cylinder direction.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[Structure of Embodiment] FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a diagram showing a refrigeration cycle of an air conditioner for a vehicle.

The refrigeration cycle 1 of the vehicle air conditioner of this embodiment is mounted on a vehicle such as an engine-mounted vehicle, an electric vehicle or a hybrid vehicle, and includes a refrigerant compressor 2, a refrigerant condenser 3, an ejector 9 and a gas-liquid compressor. This is an ejector cycle in which the separator 4 is annularly connected by the refrigerant flow path 5. In the refrigeration cycle 1, the liquid-phase refrigerant side of the gas-liquid separator 4 and the suction section of the ejector 9 are connected by a bypass flow path 6. A pressure reducing device 7 and a refrigerant evaporator 8 are provided in the middle of the bypass passage 6.

The refrigerant compressor 2 is rotationally driven by a drive source such as an engine or an electric motor mounted in an engine room of a vehicle, compresses a gas-phase refrigerant sucked into the compressor, and converts a high-temperature and high-pressure gas-phase refrigerant. This is a compressor that discharges to the refrigerant condenser 3 side. The refrigerant condenser 3 is installed in a place in the engine room of the vehicle that is susceptible to traveling wind, and the refrigerant compressor 2
Is a condenser for exchanging heat between the gaseous refrigerant discharged from the discharge port and outdoor air sent by a cooling fan (not shown) or the like to condense and liquefy the gaseous refrigerant.

The gas-liquid separator 4 is an accumulator for separating the gas-liquid two-phase refrigerant decompressed and expanded by the ejector 9 into gas and liquid. The decompression device 7 is a fixed throttle such as a capillary tube or an orifice that decompresses the liquid-phase refrigerant flowing from the liquid-phase refrigerant side of the gas-liquid separator 4 into a gas-liquid two-phase refrigerant. The refrigerant evaporator 8 is installed in an air conditioning duct (not shown), and performs heat exchange between the gas-liquid two-phase refrigerant flowing from the pressure reducing device 7 and air sent by a blower (not shown) to perform gas-liquid two-phase. An evaporator for evaporating and evaporating the refrigerant.

Next, the structure of the ejector 9 will be described with reference to FIGS. Here, FIG. 2A is a diagram illustrating a nozzle body of the ejector, and FIG. 2B is a graph illustrating a relationship between a refrigerant pressure and a sectional area ratio.

The ejector 9 corresponds to the nozzle device of the present invention, and includes an ejector main body 11 and a nozzle main body 12 provided in the ejector main body 11. The ejector main body 11 is formed of a metal material into a substantially cylindrical shape, and mixes the gas-phase refrigerant sucked from the suction part 13 in the diffuser 14 with the gas-liquid two-phase refrigerant ejected from the nozzle main body 12 and increases the pressure.

The nozzle body 12 is formed of a metal material into a substantially cylindrical shape, and converts the liquid-phase refrigerant flowing from the refrigerant condenser 3 into a gas-liquid two-phase refrigerant and jets it into the diffuser 14. A coolant passage 15 through which the coolant flows is formed inside the nozzle body 12. A first-stage throttle portion 17 and a second-stage throttle portion 18 are formed in the middle of the refrigerant passage 15. The first-stage throttle portion 17 and the second-stage throttle portion 18 are portions that reduce the liquid-phase refrigerant to a gas-liquid two-phase refrigerant by reducing the passage cross-sectional area of the refrigerant passage 15.
The outer shape on the upstream side of the nozzle body 12 is a cylindrical shape whose outer diameter does not change, whereas the outer shape on the downstream side is a truncated cone whose outer diameter gradually decreases toward the tip.

The refrigerant passage 15 is a portion corresponding to the fluid passage of the present invention. On the upstream side, the first passage 21 whose inner diameter gradually decreases from the inlet 16 of the nozzle body 12 to the throttle portion 17 is provided.
And a second passage 22 whose inner diameter gradually increases from the narrowed portion 17 to the narrowed portion 18 and then gradually decreases again. On the downstream side of the refrigerant passage 15, a third passage 23 whose inner diameter gradually increases from the throttle portion 17 to the fluid separation portion 19 where the refrigerant separation phenomenon occurs, and an inner diameter gradually increases from the fluid separation portion 19 to the jet port 20. A fourth passage 24 is provided. That is, the refrigerant passage 15 is formed such that the second spread angle (θ2) of the passage wall surface of the fourth passage 24 is smaller than the first spread angle (θ1) of the passage wall surface of the third passage 23. The first spreading angle (θ1) is 4 °
At a constant angle of about 5 °, the second spread angle (θ2) is 1
It is a constant angle of about °.

[Operation of Embodiment] Next, the operation of the refrigeration cycle 1 of this embodiment will be briefly described with reference to FIGS. Here, Gn in FIG. 1 indicates a drive flow rate, and Ge in FIG. 1 indicates a suction flow rate.

The high-temperature and high-pressure gas-phase refrigerant compressed by the refrigerant compressor 2 is condensed and liquefied by the refrigerant condenser 3 to become a high-temperature and high-pressure liquid-phase refrigerant. After that, it flows into the ejector 9. The liquid-phase refrigerant that has flowed into the nozzle body 12 of the ejector 9 is decompressed when passing through the two throttle portions 17 and 18 of the nozzle body 12 to become a gas-liquid two-phase refrigerant and become a gas-liquid two-phase refrigerant.
The gas is ejected from the second ejection port 20 into the diffuser 14.
Then, the pressure is increased when passing through the diffuser 14.

At this time, the gas phase refrigerant is sucked from the bypass passage 6 to the suction part 13 of the ejector 9 by utilizing the pressure drop around the refrigerant ejected from the nozzle body 12 at high speed.
Therefore, the gas-liquid two-phase refrigerant spouted from the spout 20 of the nozzle body 12 and the gas-phase refrigerant sucked from the suction part 13 are mixed in the diffuser 14. Thus, the gas-liquid two-phase refrigerant flowing out of the ejector 9 flows into the gas-liquid separator 4 and is separated into gas and liquid. Thereafter, the gas-phase refrigerant in the gas-liquid separator 4 is sucked into the refrigerant compressor 2 by the suction force of the refrigerant compressor 2.

The liquid-phase refrigerant accumulated at the bottom of the gas-liquid separator 4 flows into the pressure reducing device 7 by the suction effect of the suction portion 13 of the ejector 9 and is decompressed and expanded when passing through the pressure reducing device 7. And flows into the refrigerant evaporator 8 as a gas-liquid two-phase refrigerant. The refrigerant flowing into the refrigerant evaporator 8 exchanges heat with the air flowing through the duct and evaporates, and then is sucked by the suction part 13 of the ejector 9, and as described above, the nozzle body 12 in the diffuser 14. Is mixed with the gas-liquid two-phase refrigerant spouted from the spout 20 of the nozzle.

[Effects of Embodiment] As described above, the nozzle body 12 of the diffuser 14 of the present embodiment is
As shown in FIG.
The first divergence angle (θ) of the passage wall surface of the third passage 23 up to 9
By reducing the second divergence angle (θ2) of the passage wall surface of the fourth passage 24 from the fluid separation portion 19 to the jet port 20 as compared to 1), the fourth passage 24 is formed as shown in FIG. Since the separation of the gas-liquid two-phase refrigerant and the generation of the vortex from the wall surface of the passage in the passage 24 can be suppressed, the pressure drop with respect to the homogeneous flow model (shown by a broken line in the drawing) is reduced by the first and second conventional examples A,
B can be suppressed. As a result, the pressure drop of the gas-liquid two-phase refrigerant in the nozzle body 12 can be substantially entirely converted into velocity energy.

Therefore, a nozzle efficiency of 90% or more (95% in this embodiment) that can be practically used can be obtained, and the suction flow rate (Ge) of the refrigerant sucked into the suction portion 13 of the ejector 9 increases. As a result, the circulation flow rate of the refrigerant circulating through the refrigerant evaporator 8 increases. Thereby, the heat absorption performance of the refrigerant evaporator 8 is further improved, so that the cooling performance (cooling performance) of the refrigeration cycle 1 can be further improved.

Since the divergence angle is not reduced in the entire region of the refrigerant passage 15 (the third passage 23 and the fourth passage 24) from the throttle portion 18 to the jet port 20, the nozzle whose divergence angle is reduced in the entire region is reduced. As compared with the main body, the overall length of the nozzle main body 12 can be minimized. Thus, the entire length of the ejector body 11 of the ejector 9 can be shortened, so that a compact ejector 9 can be provided.

[Other Embodiments] In the present embodiment, the present invention is applied to the ejector 9 incorporated in the refrigeration cycle 1, but a nozzle device for jetting a water flow to a turbine for hydroelectric power generation, or water is jetted to a Pelton turbine. The present invention may be applied to a nozzle device that performs the following operations.

In the present embodiment, the second divergence angle (θ2) of the fourth passage 24 of the refrigerant passage 15 in the nozzle body 12 is set to a constant angle (for example, 1 °), but the second divergence angle (θ2) is set. May be changed while adjusting the spread angle to an optimum value so as to follow the pressure change of the homogeneous flow model of FIG.
However, the second divergence angle (θ2) is the first divergence angle (θ
The angle is smaller than 1).

In the present embodiment, the first spread angle (θ1)
Is set to 4 ° to 5 °, and the second spread angle (θ2) is set to 1 °.
, But the first spread angle (θ1) is 2 ° or more and 6 °
The angle may be set as follows, and the second spread angle (θ2) may be set to an angle larger than 0 ° and smaller than 2 °.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a refrigeration cycle of an air conditioner for a vehicle (embodiment).

FIG. 2A is a cross-sectional view illustrating a nozzle body of an ejector, and FIG. 2B is a graph illustrating a relationship between a refrigerant pressure and a cross-sectional area ratio (embodiment).

FIG. 3A is a cross-sectional view illustrating a nozzle body of an ejector, and FIG. 3B is a graph illustrating a relationship between a refrigerant pressure and an area of an ejection port / an area of a second-stage throttle portion (prior art). Technology).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 9 Ejector (nozzle apparatus) 11 Ejector main body 12 Nozzle main body 13 Suction part 14 Diffuser 15 Refrigerant passage (fluid passage) 16 Inlet 17 Restricted part 18 Restricted part 19 Fluid separation part 20 Spout 21 First passage 22 Second passage 23 third passage 24 fourth passage

Claims (3)

[Claims] A cylindrical nozzle body for ejecting a fluid from an ejection port provided at a tip, a fluid passage formed in the nozzle body, and a throttle provided in the middle of the fluid passage. The nozzle body, wherein the nozzle main body has a passage wall surface from the fluid separation portion to the ejection port, which is larger than a first spread angle of a passage wall surface from the throttle portion to a fluid separation portion where a fluid separation phenomenon occurs. The nozzle device, wherein the second spread angle is reduced. 2. The nozzle device according to claim 1, wherein the second spread angle is a constant angle from the fluid separation portion to the jet port. 3. The nozzle device according to claim 1, wherein the second diverging angle is changed so as to follow a change in pressure of the homogeneous flow.