JPH05157402A - Heat exchanger - Google Patents

Abstract

PURPOSE:To optimize the flow rate of a refrigerant with a simple constitution and improve thereby the heat exchanging efficiency. CONSTITUTION:A lamination type heat exchanger 1 is constituted of a refrigerant heat exchange section 7 and refrigerant evaporation section 9. The refrigerant heat exchange section 7 is for heat exchange between the refrigerant of an inlet flow channel 13 and the refrigerant of an outlet flow channel 14 by arranging the refrigerant inlet flow channel 13 and outlet flow channel 14 close to each other through a plate 12, and on the other hard the refrigerant evaporation section 9 is constituted of a plurality of evaporation flow channels 30 that branch off from the downstream end side of the inlet flow channel 13 and fins that are arranged between the evaporation channels 30 in close contact with them. Further, on the surface of the plate 12 of the refrigerant heat exchange section 7 many minute grooves are formed in order to promote heat transfer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger, and more particularly to a heat exchanger used in a refrigerating cycle such as an automobile air conditioner.

[0002]

2. Description of the Related Art Generally, a heat exchanger used in a refrigeration cycle of an air conditioner for an automobile is composed of a compressor, a condenser, a liquid receiver, an expansion valve, an evaporator, etc. By circulating the refrigerant through the circuit, heat is exchanged between the refrigerant in the evaporator and the room air to cool the room.

In the refrigeration cycle, the refrigerant adiabatically expanded through the expansion valve enters the evaporator in a two-phase flow state of gas and liquid, where it absorbs heat from the outside and evaporates (evaporates). ), The isothermal expansion is continued to perform the cooling action of the room air, and the expanded refrigerant becomes superheated vapor and is sucked into the compressor.

In recent years, a laminated heat exchanger has been developed in view of its superior performance to the conventional heat exchanger, and many tube sheets are laminated on this laminated heat exchanger. And an evaporating portion having a plurality of evaporating flow passages formed therein, a refrigerant heat exchanging portion having a plurality of tube plates stacked and different refrigerant passages (inlet and outlet) formed in close proximity to each other. Then, by distributing and supplying the refrigerant to the evaporation passage, heat exchange between the refrigerant and room air is performed, and at the same time, the refrigerant passages of the inlet and the outlet arranged close to each other flow into the evaporation portion or Refrigerants with different temperatures flowing out from the evaporation section are caused to flow to perform heat exchange between the refrigerants.

[0005]

However, since the tube sheets constituting the flow path of the laminated heat exchanger as described above are usually punched by a press and have a smooth surface, the tube sheets are separated from each other. In the refrigerant heat exchange section in which evaporation and condensation proceed and heat is exchanged, there is a problem that the efficiency of heat exchange is not necessarily high.

That is, if the surface is smooth, it is difficult to obtain boiling nuclei on the evaporation side, and the liquid film remains thick on the condensation side, so that it is difficult to achieve high heat conductivity on either side. There was a problem. The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat exchanger capable of improving the efficiency of heat exchange with a simple configuration.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a heat exchanger provided downstream of an expansion valve in a refrigeration cycle in which the refrigerant is circulated to introduce the refrigerant flowing out from the expansion valve. Is provided between the inlet flow path and the branch flow path, and a plurality of branch flow paths branching from the downstream end side of the inlet flow path into a plurality of branch flow paths that serve as evaporation regions of the refrigerant. And a fin provided in close contact with each of the branch flow passages, and an outlet flow for sending the refrigerant flowing out from the downstream end of each branch flow passage through a predetermined distance. A passage, the inlet flow passage and the outlet flow passage are arranged in proximity via a partitioning portion,
A refrigerant heat exchange part for exchanging heat between the refrigerant of the inlet flow path and the refrigerant of the outlet flow path, and a partition part of the refrigerant heat exchange part has a roughened surface, The main point is a heat exchanger.

[0008]

In the heat exchanger of the present invention having the above-mentioned structure, the refrigerant flowing out from the expansion valve is introduced into the inlet passage, passes through the predetermined distance, and is introduced into the evaporation passage through the throttle valve. Then, as the refrigerant evaporates in the evaporation passage, the temperature becomes lower,
Heat exchange between the refrigerant and air, for example. Next, the refrigerant that has passed through the evaporation passage exchanges heat with the refrigerant in the inlet passage in the refrigerant heat exchange section by passing through the outlet passage for a predetermined distance.

Particularly, in the present invention, since the surface of the partition portion of the refrigerant heat exchange portion is roughened, the following operations are performed on the evaporation side and the condensation side of the refrigerant. That is, since the refrigerant is evaporated by absorbing heat on one side and condensing the refrigerant by radiating heat on the other side across the partition part, the surface of the partition part is rough due to the formation of fine grooves or holes, for example. Since the surface is made flat, minute grooves, holes and the like serve as bubble nuclei on the evaporation surface to promote boiling heat transfer and evaporation heat transfer. On the other hand, on the condensing surface, the liquid refrigerant becomes thin due to the liquid refrigerant penetrating into the fine grooves, holes, etc., so that condensation heat transfer is promoted.

As described above, since the heat transfer properties are promoted on the evaporation side and the condensation side of the refrigerant, that is, on both sides of the partition section, the efficiency of heat exchange between the refrigerants is improved.

[0011]

EXAMPLES In order to further clarify the constitution and operation of the present invention described above, preferred examples of the heat exchanger of the present invention will be described below. As shown in FIGS. 1 and 2, a laminated heat exchanger (hereinafter, simply referred to as a heat exchanger) 1 is used in a refrigeration cycle for an automobile, and is provided downstream of an expansion valve 3.

The heat exchanger 1 is mainly equipped with a joint block 5 for introducing the refrigerant flowing out from the expansion valve 3 and for sending out the vaporized refrigerant to the outside of the heat exchanger 1, and a refrigerant heat for exchanging heat between the refrigerants. It is composed of an exchange section (super heater) 7 and a refrigerant evaporation section 9 for exchanging heat between the refrigerant and air.

The joint block 5 includes an expansion valve 3
Inlet 10 serving as an inlet for the two-phase refrigerant flowing out from the
And an outlet 11 for sending out the vaporized refrigerant. The refrigerant heat exchange portion 7 is a portion where heat is exchanged between the inlet refrigerant and the outlet refrigerant, and many plates (tube plates) 12 are laminated by brazing.

As shown in FIG. 3, the plate 12 is provided with an inlet refrigerant inflow hole 12a and an outlet refrigerant outflow hole 12b in its lower portion, and an inlet refrigerant outflow hole 12c in its upper portion.
And an outlet refrigerant inflow hole 12d are provided, and further, a plurality of concavities and convexities that form a refrigerant passage are provided in the entire central portion. That is, as shown in the cross section I-I of FIG.
By stacking the pair of plates 12 symmetrically, an inlet passage 13 and an outlet passage 14 for the refrigerant are formed adjacent to each other, and the inlet passage 13 and the outlet passage 14 respectively have an inlet refrigerant and an outlet refrigerant. Is configured to flow. Further, innumerable fine grooves 15 of about 1 to 100 μm as shown in FIG. 5 are formed on both front and back surfaces of the plate 12 by bending the plate 12 in a wave shape.

As shown in FIGS. 1 and 2, the refrigerant evaporating portion 9 has corrugated fins 26 (hereinafter referred to as fins) in the shape of a corrugated plate for cooling air, and has the irregularities shown in FIG. A large number of plates (tube plates) 27 are laminated by brazing. The plate 27 has a substantially rectangular plate shape, and a cylindrical inlet tank 28 and outlet tank 29 are provided above the plate 27.
And are formed. Inlet tank 28 and outlet tank 2
Reference numeral 9 denotes an inlet refrigerant outflow hole 12c and an outlet refrigerant inflow hole 12d formed in an upper portion of the plate 12 of the refrigerant heat exchange section 7.
Are provided at positions that match with.

The plate 27 is formed with a central concave surface portion 33 so that a refrigerant evaporation passage 30 is formed between the plates 27 when stacked, and for promoting heat transfer of the refrigerant. A plurality of cross ribs 35 and a central partition wall 3 that guides the refrigerant downward and further redirects the refrigerant to the outlet tank 29.
7 is formed in a convex shape.

When manufacturing the heat exchanger 1 having the above-described structure, first, a large number of fine irregularities are formed in advance on the press surface of a press machine (not shown), and the plate 12 and the plate are pressed at the same time. A large number of grooves 15 are formed on the surface of 12. After that, the plate 12 having the groove 15 formed therein, the plate 27 of the refrigerant evaporating portion 9, and the fins 26 are laminated, the joint block 5 is fixed, and these members are heated and brazed to be integrally joined and formed. ..

Next, the flow of the refrigerant in the heat exchanger 1 manufactured in this manner is shown by the arrows in FIGS. 1, 3 and 6. First, as shown in FIG. 1, the refrigerant sent from the expansion valve 3 to the inlet 10 of the joint block 5 is sent to each inlet tank 28 through the inlet passage 13 (FIG. 3) of the refrigerant heat exchange section 7. It is distributed here and sent to each evaporation channel 30. Then, as shown in FIG. 6, the refrigerant that has flowed into the evaporation passage 30 from the narrowed portion 34 flows downward between the central concave portions 33 while evaporating, and further changes direction at the lower portion to face upward. It flows into the outlet tank 29. Next, as shown in FIG. 1, the refrigerant merged in the outlet tank 29 is sent to the refrigerant heat exchange section 7, passes through the outlet passage 14 (FIG. 3), and reaches the outlet 11.

Next, the operation of the heat exchanger 1 configured as described above will be described with reference to FIG. FIG. 7 is a Mollier diagram showing the state of the refrigerant on the refrigeration cycle. The high-pressure refrigerant compressed by the compressor radiates heat in the condenser and undergoes a phase change from a gas refrigerant to a liquid refrigerant. Then, the refrigerant reaches the refrigerant heat exchange section 7 from the expansion valve 3, and the refrigerant heat exchange section 7 exchanges heat between the inlet refrigerant and the outlet refrigerant, thereby changing the refrigerant from point a to point b and liquefying it. That is, the inlet refrigerant condenses in the inlet passage 13 having a small diameter, but since the condensate enters the fine grooves 15 formed on the wall surface on the inlet passage 13 side to thin the liquid film, the heat transfer property is reduced. Is improved.

Next, the liquid refrigerant at the point b is decompressed to the point c by the throttle portion 34 at the inlet of the inlet tank 28 to be in a gas-liquid two-phase state, and thereafter, the inlet tank of the refrigerant evaporator 9 is reached. From 28, it is evenly distributed to each evaporation channel 30, and heat is exchanged with air via the fins 26 to start evaporation.
Next, the refrigerants are combined in the gas-liquid two-phase state at the point d in the outlet tank 29 of the refrigerant evaporation unit 9 and sent to the refrigerant heat exchange unit 7.

By passing through the outlet passage 14, the outlet refrigerant is heat-exchanged with the inlet refrigerant at points e to f to become superheated steam, and is sent to the compressor. That is, the outlet refrigerant evaporates in the outlet passage 14 having a large diameter, but the fine grooves 15 formed on the wall surface on the outlet passage 14 side serve as boiling nuclei to promote evaporation, so that the heat transfer property is improved. ing.

As described above, the heat exchanger 1 of this embodiment
According to the above, since many fine grooves 15 are formed on the surface of the plate 12 of the refrigerant heat exchange section 7, that is, the grooves 15 are formed on the surface of the inlet flow path 13 and the surface of the outlet flow path 14. Therefore, on the inlet flow path 13 side, the condensed liquid refrigerant enters the grooves 15 on the surface and the liquid film on the surface is thinned to improve the condensation heat transfer performance. On the other hand, on the outlet flow path 14 side, Since the surface grooves 15 serve as boiling nuclei to promote evaporation, the evaporation heat transfer performance is improved. As a result, the efficiency of heat transfer on both sides of the plate 12 is improved, so that high performance of the heat exchanger 1 can be realized.

The embodiment of the present invention has been described above.
The present invention is not limited to these examples, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. For example, as a method for roughening the surface of the plate 12, by brushing both surfaces of the press-molded plate 12,
Fine grooves 15 may be formed on the surface.

Alternatively, the surface of the plate 12 may be sprayed with aluminum or the like to form a porous surface. Furthermore, fine unevenness may be formed by the flux attached to the surface of the plate 12. That is, in order to prevent the oxidation of the plate 12 during brazing, a non-corrosive flux such as Nokorok (registered trademark) is applied to the surface of the plate 12, but this flux is left as it is on the surface of the plate 12. By
Fine irregularities may be formed.

In this embodiment, the refrigerant evaporating section 9 and the refrigerant heat exchanging section 7 are integrated with each other, but the refrigerant evaporating section 9 and the refrigerant heat exchanging section 7 are separated from each other and connected by a pipe or the like. May be type. For example, in the case of an automobile air conditioner, the refrigerant evaporating section 9 may be installed inside the vehicle compartment and the refrigerant heat exchanging section 7 may be installed outside the vehicle compartment and connected by piping.

[0026]

As described above in detail, according to the heat exchanger of the present invention, since the surface of the partition of the refrigerant heat exchange section is roughened, the heat transfer efficiency on the evaporation side and the condensation side of the refrigerant is high. Of the heat exchanger, thereby improving the performance of the heat exchanger. In addition, although the roughening of the partition portion can be easily realized, there is an advantage that it greatly contributes to the improvement of the heat exchange performance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is a front view showing a heat exchanger.

FIG. 3 is a plan view of a plate of a refrigerant heat exchange section.

FIG. 4 is a cross-sectional view showing a II cross section of the plate in FIG.

FIG. 5 is a perspective view showing a groove on the plate surface with a part thereof broken away.

FIG. 6 is a plan view showing a plate of a refrigerant evaporation unit.

FIG. 7 is a Mollier diagram showing the state of the refrigerant.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stacked heat exchanger (heat exchanger), 7 ... Refrigerant heat exchange part, 9 ... Refrigerant evaporation part, 12, 27 ...
Plate, 15 ... Groove, 26 ...
Corrugated fin (fin)

Claims (1)

[Claims] 1. A heat exchanger provided downstream of an expansion valve in a refrigeration cycle in which a refrigerant is circulated, wherein an inlet flow path for introducing the refrigerant flowed out of the expansion valve and passing the refrigerant through a predetermined distance is provided. A plurality of branch channels that branch from the downstream end side into a plurality of refrigerant vaporization regions, a narrowing portion that is provided between the inlet channel and the branch channel to narrow the channel area, and each of the branch channels. Fins provided in close contact with each other between the passages, an outlet passage for sending out the refrigerant flowing out from the downstream end of each branch passage after passing a predetermined distance, and a partition for the inlet passage and the outlet passage. And a refrigerant heat exchanging portion for exchanging heat between the refrigerant in the inlet passage and the refrigerant in the outlet passage, the partition portion of the refrigerant heat exchanging portion having a roughened surface. Exchange characterized by having a textured surface .