JP2000274251A - Plate fin type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate fin type heat exchanger satisfactory in heat conduction efficiency allowing improvement in heat exchange efficiency without a change in size of the heat exchanger. SOLUTION: In this plate fin type heat exchanger, plural heat transmission plates 5a, 5b are stacked opposite to each other to form gaps 5c, 6c provided with fin plates 5f, 6f, while a first fluid Ah and a second fluid Ac to exchange heat are alternately communicated the gaps 5c, 6c to exchange heat. The fin plate 5f provided in the gap 5c, through which at least the first fluid Ah of the first and second fluids Ah, Ac passes is formed with wide connection parts 5p brought into face-to-face contact with the heat transmission plates 5a, 5b, and slant fin parts connecting with the wide connection parts 5p, parallel to each other, and slant to the heat transmission plates 5a, 5b, while the slant fin parts form the sidewalls of the communicating flow cell (gap) 5c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate fin heat exchanger particularly suitable for an engine intercooler.

[0002]

2. Description of the Related Art In a supercharged engine such as a turbocharger of an automobile or the like, the air compressed by a compressor rises in temperature and expands. The supercharged efficiency and the charging efficiency are increased by cooling the heated and expanded air with an intercooler to increase the air density.

As the intercooler, a plate heat exchanger or a plate fin heat exchanger, which is compact and has excellent heat exchange performance, is often used. The heat exchange plates are formed by laminating heat transfer plates pressed into a mold, and heat exchange is performed while two fluids to be heat exchanged alternately flow through gaps (channels) formed between the heat transfer plates.

On the other hand, a plate fin type heat exchanger is obtained by adding a fin portion to a plate type heat exchanger. As shown in FIG. 1, fin plates and heat transfer plates (flat plates) are alternately stacked and bonded. As shown in FIG. 9, the side surfaces 15fs of the fin plate 15f are arranged in the gap between the heat transfer plates 15a and 15b of the plate heat exchanger, and the heat transfer plates 15a,
The same effect as when the fin portion is formed on 15b is exerted, and the heat exchange performance is improved.

The shape of the fin plates of these prior art plate-fin heat exchangers is generally, for example,
As in the case of a fin plate of a heat exchanger described in JP-A-14442 and JP-A-53-43147, the cross section of a flow cell through which a fluid flows has a corrugated, triangular or rectangular shape. It is formed in a cross-sectional shape such as a continuous waveform, a continuous triangle, or a continuous U-shape.

That is, these fin plates have not only a fin plate 15f shown in FIG. 9 but also a fin plate 25f shown in FIG. 10 as well as a fin plate 25f shown in FIG.
As described above, the flow cells 25c and 35c between the heat transfer plates 25a, 25b, 35a and 35b are formed so as to be triangular, corrugated, or the like.

[0007]

However, there is a strong demand for lighter and smaller engines in automobiles, so that it is necessary to further reduce the size of the intercooler, and it is strongly required to increase the heat transfer efficiency. Considering the shape of the fin portion of the prior art from this aspect, there are the following problems.

In other words, in the case of a rectangular flow cell 15c as shown in FIG. 9, the fin portion (side wall portion) 15fs that exerts the fin effect of the fin plate 15f is perpendicular to the heat transfer plates 15a and 15b. Since the width H of the lever fin portion 15fs is the minimum length, there is a problem that the heat transfer area is small and the improvement of the heat transfer efficiency cannot be expected.

When the distribution cells 25c, 35c are formed in a triangular or corrugated form, as in the case of the fin plates 25f, 35f having a triangular NO continuous or corrugated shape shown in FIG.
Since 35 fs becomes longer and the heat insulation area becomes larger, the heat of the fluid passing through the flow cells 25c and 35c can be efficiently transferred to the fin plate.
Heat can be transferred to 25f and 35f.

However, the fin plates 25f, 35 shown in FIG.
f, the portions that come into contact with and contact the heat transfer plates 25a, 25b, 35a, and 35b come into linear contact, and the heat transfer surface becomes very small. Board
The heat transfer efficiency to the heat transfer plates 25a, 25b, 35a, 35b is poor because the heat transfer efficiency to the heat transfer plates 25a, 25b, 35a, 35b cannot be efficiently transferred to the heat transfer plates 25a, 25b, 35a, 35b. However, there is a problem that heat cannot be efficiently transferred to the other fluid.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to improve the heat exchange efficiency without changing the size of the heat exchanger. To provide an exchange.

[0012]

A plate fin type heat exchanger for achieving the above object is formed by laminating a first fluid and a second fluid for heat exchange on a plurality of heat transfer plates facing each other. In a plate-fin heat exchanger in which fin plates are provided in the gaps while alternately circulating heat through the gaps, the fin plates are disposed in the gaps through which at least one of the first fluid and the second fluid passes. The fin plate is formed of a wide connecting portion that is in surface contact with the heat transfer plate, and parallel slanted fin portions that are connected to the wide connecting portion and are inclined with respect to the heat transfer plate. The side wall of the distribution cell is formed by the fin portion.

Further, an intercooler of the supercharged engine is formed by the plate fin type heat exchanger, and the inclined fin portion is disposed in the gap through which the high-temperature side compressed air flows.
This heat transfer plate is formed of a corrosion-resistant material such as stainless steel or titanium, and the fin plate is often formed of a material such as aluminum, stainless steel, or copper.

According to the plate fin type heat exchanger having the above structure, since the cross section of the flow cell is a parallelogram, the width of the inclined fin portion is larger than the distance between the heat transfer plates. The heat transfer area of the part is large, the heat transfer efficiency from the fluid to the fin plate is improved, and the wide connecting part is in surface contact with the heat transfer plate, so the heat transfer from the fin plate to the heat transfer plate is good, The efficiency of heat exchange between one fluid and the other fluid is improved.

That is, the fin portion of the plate fin type heat exchanger is provided not so as to be perpendicular to the heat transfer plate but inclined so that the cross section of the flow cell becomes a parallelogram. As the contact area with the fluid flowing inside, that is, the heat transfer area increases, and the wide connecting portion which comes into surface contact with the heat transfer plate increases the heat transfer efficiency between the fin plate and the heat transfer plate, so that the overall heat Transmission efficiency is improved.

In particular, the increase in the heat transfer area due to the inclined fin portion and the wide connecting portion is limited to a size, such as an intercooler provided for lowering the temperature of intake air of a supercharged engine of an automobile and increasing the amount of intake air. This is effective when there is difficulty in improving heat transfer efficiency.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a plate fin type heat exchanger according to an embodiment of the present invention will be described with reference to the drawings, taking an intercooler of a supercharged engine as an example.

As shown in FIG. 1, an intercooler 1, which is a plate-fin heat exchanger, includes a first fluid inlet header 2 for a first fluid, which is a high-temperature fluid, which communicates with a compressor on the supercharger side, and an engine. And a first fluid outlet head 3 that communicates with the intake manifold. Further, a second fluid inlet header 8 and a second fluid outlet header 9 for a second fluid, which is a low-temperature fluid, are provided on both sides of the heat exchange unit 4, and cooling air Ac flows through the heat exchange unit 4. It is configured so that it can be distributed.

As shown in FIGS. 1 and 2, the heat exchange section 4 is a flat tube 5 formed by processing a cylinder into a flat shape.
Are formed by laminating the fin plate 6f therebetween. That is, the heat exchange portions 4 are formed by forming the heat transfer surfaces 5a and 5b at the flat portions of the tubes 5 and laminating the gaps 5c inside the tubes 5 and the gaps 6c outside the tubes 5 with each other.

An inclined fin plate 5f is provided in the gap 5c between the heat transfer plates 5a and 5b. The inclined fin plate 5f includes a wide connecting portion 5p in surface contact with the heat transfer plates 5a and 5b, and parallel inclined fins connected to the wide connecting portion 5p and inclined with respect to the heat transfer plates 5a and 5b. 5 fs.

The inclined fin portion 5fs is called an inner fin, and is inclined with respect to the heat transfer plates 5a and 5b which are parallel to each other and face each other, as shown in FIG. 3 (b). Inclination angle θ with respect to vertical surface 5h of hot plates 5a, 5b
> 0. This inclination allows the compressed air Ah, which is a high-temperature fluid, to pass therethrough, and the cross section of the first fluid side flow cell 5c having the inclined fin portion 5fs as a side wall is formed in a parallelogram.

As shown in FIG. 3B, when the inclination angle θ from the vertical plane is increased, the width B increases and the heat transfer area also increases, but the flow cell 5c becomes flat and the flow resistance increases. The angle is most preferably 10 to 45 degrees, and is most preferably 10 to 45 degrees from the balance between the increase in the flow resistance and the increase in the heat transfer surface. Then, as shown in FIG. 4A, the ends of the inclined fin portions 5fs are alternately connected by the wide connecting portions 5p to form the inclined fin plate 5f.

On the other hand, a fin plate 6f having a fin portion 6fs called an outer fin is sandwiched between the tubes 5, and the tubes 5 and the fin plates 6f are alternately laminated to form a fin plate 6f. A flow cell 6c on the second fluid side through which the cooling air low Ac flows is formed.

As shown in FIG. 2, the fin plate 6f of the outer fin is formed in a continuous sine shape. In addition to the sine shape, the cross-section of the flow cell 6c on the second fluid side is triangular or rectangular. Etc. can also be formed. Also,
Similarly to the inclined fin plate 5f, the flow cell 6c on the second fluid side
Can also be formed so that the cross section of the shape becomes a parallelogram.

The heat exchange part 4 is formed by laminating the tube 5 and the fin plate 6f, and the first fluid inlet header 2 and the first fluid outlet which respectively combine the inlet side and the outlet side of the flow cell 5c on the first fluid side. A header 3 is provided, and a second fluid inlet header 8 and a second fluid outlet header 9 are provided to combine the inlet side and the outlet side of the flow cell 6c on the second fluid side.

As shown in FIG. 2, the direction of the tube 5 and the fin plate 6f, that is, the first fluid Ah
When the flow direction of the second fluid Ac of the low-temperature side fluid is a cross flow (cross flow), the headers 2 and 3 on the first fluid side and the headers 8 and 9 on the second fluid side are separated in different directions (X, Y). Although it is preferable because it can be easily manufactured, a countercurrent type can also be used.

The tube 5 forming the facing heat transfer plates 5a and 5b is formed of a corrosion-resistant material such as stainless steel or titanium, and the inclined fin plate 5f is formed of a material such as aluminum, stainless steel or copper. The fin plate (outer fin) 6f is formed of a material such as aluminum, stainless steel, or copper. And the inclined fin plate 5f in this tube 5
Is processed and inserted into the tube 5 in the following manner.

First, in the first method, as shown in FIG. 5, the inclined fin plate 5f is provided with a fin material plate 5t between press dies 50a and 50b provided with inclined projections. It is formed by moving the press dies 50a and 50b in the direction S and pressing.

In the second method, the inclined fin plate 5f
Is a normal vertical fin press type as shown in FIG.
After the fin material plate 5t is placed between 51a and 51b and pressed in the vertical direction N, when the press dies 51a and 51b are separated, the press dies 51a and 51b are moved in opposite lateral directions T, respectively. It is formed.

In the third method, the inclined fin plate 5f is formed by placing the fin material plate 5t between the inclined press dies 52a and 52b and pressing in the vertical direction N as shown in FIG. .

Further, in the fourth method, as shown in FIG. 8, press rollers 53a to 53e having an uneven surface are provided in multiple stages, and the fin material plate 5t is connected to these press rollers 53a.
By passing between a to 53e, the unevenness is gradually deepened and inclined to form the inclined fin plate 5f.

As shown in FIG. 4, the inclined fin plate 5f manufactured by these methods is cut at both ends to adjust the size. An adhesive is applied to a portion 5ps outside the portion 5p and inserted into the tube 5, and after insertion, the adhesive is heated to melt the adhesive, and then cooled and solidified to form the wide connecting portion 5p. Is adhered to the heat transfer surfaces 5a and 5b which are the inner surfaces of the tube 5, and the inclined fin plate 5f is fixed in the tube 5.

Next, the heat exchange in the plate fin type heat exchanger (intercooler) 1 will be described. The high-temperature air (first fluid) Ah compressed by the supercharger is introduced into the tube 5 of the heat exchange unit 4 from the first fluid inlet header 2 and passes through the first fluid-side flow cell 5c to the first fluid. It is discharged to the exit header 3. On the other hand, cooling air (second fluid) Ac
From the second fluid inlet header 8 to the tube 5 of the heat exchange section 4
It is introduced into the outer fin plate 6f and is discharged to the second fluid outlet header 9 through the inside of the second fluid side flow cell 6c.

At this time, the heat of the high-temperature compressed air Ah passing through the flow cell 5c on the first fluid side passes through the inclined fin portion 5f and the heat transfer plates 5a and 5b, that is, through the tube 5, It is transmitted to the fin plate 6f. Then, the low-temperature air Ac, which is the outside air for cooling, passing through the inside of the flow cell 6c on the second fluid side comes into contact with the fin plate 6f and the heat transfer plates 5a and 5b, and takes away the heat transferred.

By this heat exchange, the heat of the high-temperature compressed air Ah is transmitted to the low-temperature cooling air Ac introduced from the front of the vehicle, and the compressed air Ah is cooled. [Effect] According to the intercooler 1 having the above configuration, the first
Since the inclined fin portion 5fs is inclined with respect to the heat transfer surfaces 5a and 5b in a cross section perpendicular to the flow direction of the compressed air Ah, which is a fluid, and is arranged so as to be parallel to each other. The contact surface area between the air Ah and the inclined fin plate 5f, that is, the heat transfer area,
Since a large contact area with the a and 5b, that is, a heat transfer area can be secured at the same time and the heat transfer path to the tube 5 can be increased, the cooling efficiency can be increased.

According to the experimental results, when the flow cell 5c is formed in a parallelogram as shown in FIG. 3, the side surface 15fs of the fin plate 15f as shown in FIG.
Was raised vertically, that is, by about 80% of the thermal efficiency of the intercooler in which the flow cell 15c was made rectangular, and the temperature was further increased by 2 to 3%.

Therefore, the heat transfer efficiency of the intercooler 1 can be improved, the intake air temperature of the air Ah that has been heated and expanded by the compressor of the supercharger can be reduced, the density can be increased, and the combustion temperature can be reduced. NOx can be reduced, and the amount of air supplied to the cylinder can be increased to increase the charging efficiency and bring about good combustion.

[0038]

As described above, according to the plate fin type heat exchanger of the present invention, the cross section of the flow cell is a parallelogram, and the width of the inclined fin portion is larger than the distance between the heat transfer plates. In addition, since the heat transfer area of the inclined fin portion is increased, and the wide connecting portion also has a heat transfer area, the efficiency of heat transfer from the fluid to the fin plate can be improved. And
A large heat transfer area can be obtained, and heat transfer efficiency can be improved.

Further, since the wide connecting portion is brought into surface contact with the heat transfer plate, heat transfer from the fin plate to the heat transfer plate can be improved, and as a result, the space between the first fluid and the second fluid can be improved. Can improve the heat exchange efficiency.

In particular, the present invention is effective in a case where it is difficult to improve the heat transfer efficiency due to a limited size, such as an intercooler provided for lowering the temperature of intake air and increasing the amount of intake air in a supercharged engine of an automobile. In addition, the intake air temperature can be efficiently reduced, thereby lowering the combustion temperature and reducing NOx.

[Brief description of the drawings]

FIG. 1 is a diagram of an intercooler according to an embodiment of the present invention, wherein (a) is a front view, (b) is a side view, and (c) is a plan view.

FIG. 2 is a partial perspective view of an intercooler showing a heat exchange unit of FIG. 1;

3A and 3B are cross-sectional views of a tube showing an inner fin according to the present invention, wherein FIG. 3A is an overall cross-sectional view and FIG. 3B is an enlarged partial cross-sectional view.

4A and 4B are diagrams showing a relationship between the inclined fin plate and the tube according to the present invention, wherein FIG. 4A shows a state before the inclined fin plate is inserted, and FIG. 4B shows a state after the inclined fin plate is inserted.

FIGS. 5A and 5B are schematic views showing a first method for forming the inclined fin plate according to the present invention, wherein FIG. 5A shows a state before pressing, FIG. 5B shows a state when pressed, and FIG.

FIGS. 6A and 6B are schematic views showing a second method for forming the inclined fin plate according to the present invention, wherein FIG. 6A shows a state before pressing, FIG. 6B shows a state when pressed, and FIG.

FIGS. 7A and 7B are schematic views showing a third method of forming the inclined fin plate according to the present invention, wherein FIG. 7A shows a state before pressing, FIG. 7B shows a state when pressing, and FIG.

FIG. 8 is a schematic view showing a fourth method for forming the inclined fin plate according to the present invention, and schematically shows a method using a roller press.

FIGS. 9A and 9B are cross-sectional views of a tube showing an inner fin according to the related art, wherein FIG. 9A is an overall cross-sectional view and FIG. 9B is an enlarged partial cross-sectional view.

FIG. 10 is an enlarged sectional view of a tube showing another inner fin of the prior art, wherein (a) shows an inner fin having a triangular shape, and (b) shows an inner fin having a corrugated shape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intercooler (plate fin type heat exchanger) 2 1st fluid inlet head 3 1st fluid outlet head 4 Heat exchange part 5 Tube 5a, 5b Heat transfer surface 5c Flow cell on 1st fluid side 5f Inner fin (inclined fin part) 6) Fin plate 6c Flow cell on second fluid side 6f Outer fin 8 Second fluid inlet head 9 Second fluid outlet head Ac Low temperature air (second fluid) Ah Compressed air (first fluid)

Claims (2)

[Claims] A first fluid and a second fluid for heat exchange are alternately circulated through a gap formed by stacking a plurality of heat transfer plates facing each other to exchange heat, and a fin plate is provided in the gap. In the plate fin type heat exchanger provided, the fin plate disposed in the gap through which at least one of the first fluid and the second fluid passes is formed in a wide width so as to make surface contact with the heat transfer plates (5a, 5b). A connecting portion, connected to the wide connecting portion, and
A plate-fin type heat exchanger, wherein the heat-transfer plate is formed of parallel slanted fin portions which are slanted with respect to the heat transfer plate, and the slanted fin portions form side walls of the flow cell. 2. The heat exchanger according to claim 1, wherein the plate fin heat exchanger is an intercooler of a supercharged engine, and the inclined fin portion is disposed in the gap through which high-temperature side compressed air flows. Plate fin heat exchanger.