JP2001336885A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger capable of increasing a heat exchanging amount, compacting and reducing in weight by improving a heat transfer rate. SOLUTION: The heat exchanger heat exchanges by allowing a refrigerant to flow into a plurality of tubes of flat shape. The tubes (12, 50 and 70) respectively have first surfaces (26 and 62) and second surfaces (28 and 54) opposed apart substantially in parallel with each other, and have a plurality of recesses (32 and 56) formed in a zigzag state on at least one of the first and second surfaces in such a manner that a flowing direction of the refrigerant is in a longitudinal direction and contacted with the other opposed surface. Further, a plurality of cooling grooves (34 and 72) are formed along a direction inclined at a prescribed angle to the flowing direction of the refrigerant on inside surfaces of the first and second surfaces of the respective tubes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat exchanger,
In particular, the present invention relates to a heat exchanger using a tube applicable to a vehicle air conditioner or the like.

[0002]

2. Description of the Related Art Conventionally, in a heat exchanger used in a vehicle air conditioner, a tube for a heat exchanger is used, and these are roughly classified into types shown in FIGS. . FIG. 9 shows a so-called electric resistance welded tube 1. The electric resistance welded tube 1 includes a flat tube 2 and a corrugated inner fin 4 inserted into an opening 3 of the tube 2. The tops 4a of the inner fins 4 are fixed to the inner surface of the tube 2 by welding or the like. FIG. 10 shows an extruded tube 5,
The extruded tube 5 is formed by integrally extruding a tube portion 6 and a wall surface 7.

[0003]

However, in the case of the heat exchanger using the electric resistance welded tube 1 shown in FIG. 9, the inner fin 4 inserted into the opening 3 of the tube 2 has a corrugated shape.
Is changed to increase the heat transfer area in contact with the refrigerant flowing through the tube 2 and improve the heat transfer coefficient. However, the processing of the inner fin 4 is restricted, and the improvement of the heat transfer coefficient is not It is almost the limit. In the case of the heat exchanger using the extruded tube 5 shown in FIG. 10, by changing the pitch of the wall surface 7 in the tube portion 6, the heat transfer area in contact with the refrigerant flowing in the tube 2 is enlarged, Although the heat transfer coefficient is improved, the tube 6 and the wall 7
It is difficult to further reduce the wall thickness, and the improvement of the heat transfer coefficient is almost at its limit.

Accordingly, the present invention has been made to solve the problems of the prior art, and has been made to improve the heat transfer coefficient, thereby increasing the amount of heat exchange, making the heat exchanger compact and lightweight. It is intended to provide an exchanger.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention provides a heat exchanger for exchanging heat by flowing a refrigerant into a plurality of tubes having a flat shape. A first surface and a second surface which are substantially parallel to each other and are opposed to each other, and at least one of the first surface and the second surface is staggered with a plurality of depressions whose longitudinal direction is the flow direction of the refrigerant. And the plurality of recessed portions abut on other surfaces facing each other. Furthermore, the inner surfaces of the first surface and the second surface of the tube have a predetermined angle with respect to the flow direction of the refrigerant (preferably, (About 5 degrees to about 30 degrees). A plurality of cooling grooves are formed along the inclined direction.

In the present invention configured as described above,
Since at least one of the first surface and the second surface of the tube is formed in a staggered manner with a plurality of depressions whose longitudinal direction is the flow direction of the refrigerant, the flow of the refrigerant is on the front side of the depressions. Since it collides and then flows along the depression, the boundary layer of the refrigerant is kept thin, so that a high heat transfer coefficient can be obtained. Further, since a plurality of cooling grooves are formed on the inner surfaces of the first surface and the second surface of the tube along a direction inclined at a predetermined angle with respect to the flow direction of the refrigerant, disturbance of the flow of the refrigerant is reduced. A higher heat transfer rate is obtained because of the enhanced heat transfer area.

In the present invention, it is preferable that the depression has an elliptical or elliptical shape having a major axis in the longitudinal direction. In the present invention, the plurality of cooling grooves are preferably formed so as to alternately intersect along a direction inclined at a predetermined angle (preferably, about 5 degrees to about 30 degrees) with respect to the longitudinal direction.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing an embodiment of the heat exchanger of the present invention, FIG. 2 is a partial perspective view of a tube used in the heat exchanger of FIG. 1, and FIG. FIG. 4 is a sectional view taken along the line, and FIG. 4 is a partial plan view of the tube of FIG. 2. As shown in FIG.
The heat exchanger 10 of the present embodiment includes a plurality of flat tubes 12 and a pair of heads provided at both ends of the tubes 12 so as to communicate with inner portions (flow paths) of the tubes 12. Corrugated fins 16 arranged between pipes 14 and 15 and a plurality of tubes 12, some of which are in contact with each tube 12.
And In addition, the head pipe 14 on the left
A refrigerant inlet pipe 18 is attached to the upper side of the head, and a refrigerant outlet pipe 20 is attached to the lower side of the head pipe 15 on the right side in the drawing. Here, a partition plate 22 is provided slightly below the middle of the head pipe 14 on the left side in the figure, so that the gas refrigerant and the liquid refrigerant are not mixed. In the heat exchanger 10, the refrigerant flows from left to right in the upper region a, and flows from right to left in the lower region b, as shown by the arrow A. It is a heat exchanger. The present invention can be applied not only to the opposed heat exchanger, but also to a one-way heat exchanger and other types of heat exchangers.

As shown in FIGS. 2 to 4, the tube 12 used in the heat exchanger 10 of the present embodiment has a first surface 26 and a second surface 28 which are formed by bending a flat plate 24. A coolant passage 30 is formed in a portion surrounded by the first surface 26 and the second surface 28. Dimples 32, which are concave portions, are provided on both surfaces of the first surface 26 and the second surface 28, respectively.
Are formed. As shown in FIG. 3, dimples 32 formed on both of the first surface 26 and the second surface 28 are provided.
Have their bottom surfaces 32a in contact with each other in the flow path 30 and are joined by a brazing or the like. In FIG. 3, a description of a cooling groove 34 described later is omitted. Further, as shown in FIG. 4, these dimples 32 are formed in an oval or elliptical shape whose longitudinal direction is the flow direction A of the refrigerant flowing in the tube 12. These dimples 32 are arranged in a zigzag pattern along the flow direction A of the refrigerant at a predetermined interval. As described above, since a plurality of dimples 32, which are depressions having the longitudinal direction of the refrigerant flow direction, are formed and arranged in a staggered manner, the refrigerant flow collides with the front side of the dimples 32. Since the turbulence increases and then flows along the dimple 32, the boundary layer of the refrigerant is kept thin. As a result, a high heat transfer coefficient is obtained.

Further, the first surface 26 and the second surface 26 of the tube 12
A plurality of cooling grooves 34 are formed on the inner surface of each of the 28 along a direction inclined by a predetermined angle θ with respect to the flow direction A of the refrigerant. These cooling grooves 34 are formed between the first surface 26 and the second surface 26.
Since the surface 28 is formed by bending the flat plate 24, it is formed in the same direction when the tube 12 is unfolded, but in the tube 12 formed state, it is in the opposite direction when viewed in plan. The predetermined angle θ is an angle at which the turbulence of the refrigerant is promoted, and is preferably about 5 degrees to about 30 degrees, and most preferably about 15 degrees to about 20 degrees. This is because a flow along the cooling groove 34 occurs while maintaining the speed of the refrigerant in the tube 12. If the angle θ is too large, the turbulence of the refrigerant becomes too large, and the flow resistance (pressure loss on the refrigerant side) is reduced. The reason for this is that the effect of reducing the flow rate due to the pressure loss and the performance decrease due to the change in the temperature of the refrigerant become greater than the effect of improving heat transfer. In consideration of such a pressure loss of the refrigerant, the effect of improving the heat transfer coefficient increases in the range of the angle θ. As a result, a plurality of cooling grooves 34 are formed on the inner surfaces of the first surface 26 and the second surface 28 of the tube 12 along a direction inclined at a predetermined angle θ with respect to the flow direction A. In addition, the disturbance of the flow of the refrigerant is promoted, and the heat transfer area is increased, so that a higher heat transfer rate can be obtained.

The tube 12 has a leading edge portion 36 and a trailing edge portion 38 in the inflow direction B of air for performing heat exchange. The leading edge portion 36 and the trailing edge portion 38 have a predetermined thickness. Splitter plate portions 40 and 42 each having a function of rectifying the flow of the inflow air around the tube 12 are formed to be thin. In the present embodiment, the leading edge 36
The rear edge 38
Only the splitter plate section 42 may be provided.

Next, the operation and effect of the heat exchanger according to the present embodiment will be described. First, according to the present embodiment, since the plurality of dimples 32, which are depressions whose longitudinal direction is the flow direction of the refrigerant, is formed and arranged in a staggered manner, the flow of the refrigerant is Since the collision with the front side of the turbulence increases and then flows along the dimple 32,
The boundary layer of the refrigerant is kept thin. As a result, a high heat transfer coefficient is obtained.

Second, according to the present embodiment, the tube 12
A plurality of cooling grooves 34 are formed on the inner surface of each of the first surface 26 and the second surface 28 along a direction inclined by a predetermined angle θ with respect to the flow direction A. Turbulence is promoted, and the heat transfer area is increased, so that a higher heat transfer coefficient can be obtained.

Third, according to the present embodiment, since the flat plate 24 which is a plate material is manufactured by bending or the like, a tube is required.
12 can be formed thinner than the conventional extruded tube 5 shown in FIG. Specifically, in the conventional extruded tube 5, since the tube is manufactured by extrusion, the minimum wall thickness is 0.25 mm due to manufacturing limitations. On the other hand, in the tube 12 according to the present embodiment, 0.25
It is possible to make the thickness less than mm.

Fourth, since the splitter plate portions 40 and 42 are formed on the front edge 36 and the rear edge 38 of the tube 12 of the heat exchanger 10 of the present embodiment, the rear edge of the tube 12 Even if the flow separates in the vicinity, the splitter plate part 38, 40
As a result, the formation of a vortex street is hindered, and only a vortex street smaller than the conventional one is generated. Further, since the flow around the tube 12 is rectified by the splitter plate portions 38 and 40, the noise level accompanying the air flow can be reduced.

Fifth, in the present embodiment, a plurality of dimples 32 are formed, and the opposing bottom portions 32a of these dimples 32 are joined by brazing.
Strength is improved. As a result, if the strength is the same as that of the conventional extruded tube 5, the present embodiment can reduce the wall pressure of the tube 12.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a partial plan view showing a tube according to another embodiment used in the heat exchanger of the present invention, and FIG. 6 is a sectional view taken along the line VI-VI of FIG. In this embodiment, the tubes 50 used in the heat exchanger
Has a flat shape due to the first surface 52 and the second surface 54. In the tube 50, a plurality of dimples 56 are formed only on the first surface 52 side. Therefore, the first surface
The bottom portion 56a of the dimple 56 formed on the inner surface 52 and the inner surface of the second surface 54 are in contact with each other and are joined by a brazing or the like. Further, a cooling groove (not shown) is formed on the inner surface of the tube 50 along a direction inclined by a predetermined angle θ with respect to the direction of the flow of the refrigerant. Others are the same as those of the embodiment shown in FIGS. 1 to 4, and can exhibit the same excellent operational effects as described above.

Further, another embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a partial plan view showing the inner surface of one surface of a tube according to still another embodiment used in the heat exchanger of the present invention, and FIG. 8 is a partial plan view of the tube used in the heat exchanger of the present invention. FIG. 10 is a partial plan view showing an inner surface of one surface of a tube according to another example of another embodiment. As shown in FIGS. 7 and 8, in this embodiment, a plurality of cooling grooves 72 are inclined at a predetermined angle with respect to the longitudinal direction on the inner surface of each of the first surface and the second surface of the tube 70. It is formed so as to intersect alternately along the direction. The predetermined angle in this embodiment is the same as the predetermined angle θ in the embodiment shown in FIG.
Degrees are preferred, and especially about 15 to about 20 degrees is optimal. According to this embodiment, similarly to the above-described embodiment, the disturbance of the flow of the refrigerant is promoted, and the heat transfer area is increased, so that a higher heat transfer coefficient can be obtained.

[0019]

As described above, according to the heat exchanger of the present invention, it is possible to improve the heat transfer coefficient, thereby increasing the heat exchange capacity of the heat exchanger. Further, since the heat transfer coefficient is improved, the heat exchanger can be made compact and lightweight.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a heat exchanger of the present invention.

FIG. 2 is a perspective view showing a tube used in the heat exchanger of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a partial plan view of the tube of FIG. 2;

FIG. 5 is a partial plan view showing a tube according to another embodiment used in the heat exchanger of the present invention.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is a partial plan view showing an inner surface of a tube according to still another embodiment used in the heat exchanger of the present invention.

FIG. 8 is a partial plan view showing another example of still another embodiment shown in FIG. 7;

FIG. 9 is a perspective view showing an example of a heat exchanger tube used in a conventional heat exchanger.

FIG. 10 is a perspective view showing another example of a heat exchanger tube used in a conventional heat exchanger.

[Explanation of symbols]

 10 Heat exchanger 12,50,70 Tube 24 Flat plate 26,52 First surface 28,54 Second surface 30 Flow path 32,56 Dimple (dent) 34,72 Cooling groove A Coolant flow direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masashi Inoue 3-1-1 Asahimachi, Nishi-Biwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside the Cooling Business Division, Mitsubishi Heavy Industries, Ltd. (72) Inventor Hirohiro Nakato Nishi-Biwajima, Nishi-Kasugai-gun, Aichi Prefecture 3-1-1 Asahi-cho, Municipal Mitsubishi Heavy Industries, Ltd. Cooling Business Division F-term (reference) 3L103 AA05 AA37 BB38 CC22 CC28 DD06 DD32 DD36

Claims (4)

[Claims] 1. A heat exchanger for exchanging heat by flowing a refrigerant into a plurality of tubes having a flat shape, wherein said tubes are separated from each other in a substantially parallel manner so as to face a first surface and a second surface.
A plurality of depressions having a longitudinal direction in the flow direction of the coolant are formed in at least one of the first surface and the second surface in a zigzag manner, and the plurality of depressions are opposed to each other. A plurality of cooling grooves are formed on the inner surface of each of the first surface and the second surface of the tube along a direction inclined at a predetermined angle with respect to the flow direction of the refrigerant. Characterized heat exchanger. 2. The heat exchanger according to claim 1, wherein the depression is an ellipse or an ellipse having a major axis in a longitudinal direction. 3. The heat exchanger according to claim 1, wherein the plurality of cooling grooves are formed so as to intersect alternately along a direction inclined at a predetermined angle with respect to the longitudinal direction. 4. The heat exchanger according to claim 1, wherein the predetermined angle is about 5 degrees to about 30 degrees.