JP4690605B2 - Corrugated fin heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchanger having a number of flat tubes spaced at regular intervals and corrugated fins arranged between them, based on the relationship between the louver raising angle and the amount of heat radiation at each position of the corrugated fins. The invention relates to an improvement in heat exchange performance.
[0002]
[Prior art]
A large number of louvers are cut and raised on the surface of the fins of the corrugated fin heat exchanger slightly spaced apart in the air flow direction.
FIG. 12 is a longitudinal cross-sectional explanatory view of a main part of a fin of a conventional corrugated fin type heat exchanger, and an air flow 5 flows from left to right in the figure. A return louver 4 is arranged in the center of the corrugated fin 2 in the width direction, and the inclination direction of the louver 3 is cut and raised in the opposite direction before and after the return louver 4 as a boundary. That is, each louver 3 in the leeward louver group 3a is inclined to the left upward, and each louver 3 in the leeward louver group 3b is inclined to the right upward. The cut-and-raised inclination angles α of the leeward louver group 3a and the leeward louver group 3b are formed to be the same.
[0003]
[Problems to be solved by the invention]
In the conventional corrugated fin heat exchanger as shown in FIG. 12, the air flow 5 flows from the left end to the right end, and the difference between the temperature of the air flow 5 at each position in the flow direction and the temperature of the fin surface is As shown in FIG. 13, it was confirmed by the inventors' experiment. That is, the temperature difference between the airflow 5 and each part of the fin is rapidly reduced by each louver 3 of the windward louver group 3a located between the left end of the corrugated fin 2 and the return louver 4. On the other hand, on the leeward side of the return louver 4, the decreasing rate of the temperature difference between the air flow 5 and each fin portion is relatively small, and there is almost no temperature difference at the right end portion of the corrugated fin 2.
[0004]
This indicates that the amount of heat released from the leeward louver group 3b with respect to the return louver 4 is significantly smaller than that of the leeward louver group 3a. Nevertheless, the pressure loss of the airflow in the leeward louver group 3b is equivalent to that of the leeward louver group 3a.
Based on the knowledge of the above experimental results, the present inventors have developed a corrugated fin type heat exchanger with a small pressure loss of the air flow and high heat dissipation performance as a whole.
[0005]
[Means for Solving the Problems]
The present invention according to claim 1 is located between a plurality of flat tubes (1) arranged at regular intervals and an adjacent flat tube (1), and the longitudinal direction of the cross section of the flat tubes (1) A plurality of corrugated fins (2) whose tops and troughs, which correspond to the width direction of the wave, are fixed to the outer surface of the flat tube (1).
In the corrugated fin type heat exchanger in which the air flow (5) flows in the long axis direction of the flat tube (1),
In the corrugated fin (2), a large number of louvers (3) are formed obliquely spaced apart from each other in the width direction, and a return louver (4) is disposed in the middle, and the return louver The only leeward louver group (3a) located upstream of the air flow (5) and the only leeward louver group (3b) located downstream of the air flow (5) via The cutting and raising direction of (3) is formed in reverse,
Corrugated fin type heat exchanger in which the cut-and-raised angle β of each louver (3) of all leeward louver groups (3b) is smaller than the cut-and-raised angle α of all louver groups (3a) on the leeward side It is.
[0006]
The present invention according to claim 2 is the method according to claim 1,
This is a corrugated fin heat exchanger in which the louver width (S2) of each louver (3) of the leeward louver group (3b) is formed larger than the louver width (S1) of the leeward louver group (3a).
The present invention according to claim 3 provides the method according to claim 1,
This is a corrugated fin heat exchanger in which the group width (L2), which is the entire width of the leeward louver group (3b), is formed larger than the group width (L1) of the leeward louver group (3a).
[0007]
The present invention according to claim 4 provides the method according to claim 1,
This is a corrugated fin heat exchanger in which the group width (L2), which is the entire width of the leeward louver group (3b), is smaller than the group width (L1) of the leeward louver group (3a).
The present invention according to claim 5 provides the method according to any one of claims 1 to 4,
The cut-and-raised angle α of each louver (3) in the leeward louver group (3a) is 24 to 30 degrees, and the cut-and-raised angle β of each louver (3) in the leeward louver group (3b) is 11 to 23 degrees. The corrugated fin-type heat exchanger has a fin width B in the air flow direction of the corrugated fin (2) of 24 mm to 64 mm.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, each embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal cross-sectional explanatory view of a main part of a corrugated fin 2 of a corrugated fin type heat exchanger according to the present invention, and is a schematic cross-sectional view taken along line II in FIG. FIG. 5 schematically shows only one corrugated fin 2, but actually a large number of flat tubes 1 and corrugated fins 2 are arranged in parallel at regular intervals.
[0009]
That is, in this corrugated fin type heat exchanger, a large number of flat tubes 1 are arranged at regular intervals and in a plurality of rows, and corrugated fins 2 are positioned between the flat tubes 1, and the top portions are both ends of the wave amplitude direction. The troughs are fixed to the outer surface of the flat tube 1 by means such as brazing to constitute a core, and both ends of each flat tube 1 are fixed in fluid-tight communication with a pair of tanks (not shown). Then, a fluid to be cooled flows from one tank to the other tank through a number of flat tubes 1, and an air flow 5 for cooling flows in the width direction on the outer surface of the flat tubes 1 and the corrugated fins 2. Exchange is to be performed.
[0010]
In FIG. 1, the air flow 5 flows from the left end to the right end. The return louver 4 is positioned at the center of the corrugated fin 2 in the width direction, and only one group of the windward louver group 3a is provided on the left side of the return louver 4, and only one group of the leeward louver group 3b is provided on the right side. Yes. The cut-and-raised angle β of each louver 3 of the leeward louver group 3b is formed smaller than the cut-and-raised angle α of each louver 3 of the leeward louver group 3a, and the air resistance of the leeward louver group 3b to the air flow 5 is reduced. It comes to reduce.
In this example, the group width L1 of the leeward louver group 3a and the group width L2 of the leeward louver group 3b are the same. The corrugated fin 2 has a fin width B of 24 mm to 64 mm, a cut-and-raised angle α of the louver 3 of the windward louver group 3a is 24 to 30 degrees, and a cut-and-raised angle of each louver 3 of the leeward louver group 3b. β is 11 degrees to 23 degrees.
[0011]
Next, FIG. 2 shows a second embodiment of the present invention. This embodiment is different from that of FIG. 1 in that the louver width S2 of each louver 3 in the leeward louver group 3b is different from the leeward louver group 3a. Each louver 3 is cut and raised larger than the louver width S1, and the others are the same. 1 to 4 (FIGS. 3 and 4 will be described later) each have a smaller number of louvers than the actual corrugated fins, and others are simplified, but as an example, the corrugated fin type of FIG. The heat exchanger is actually formed as shown in FIGS.
[0012]
This heat exchanger is an example in which the fin width B is 36 mm, the width and the louver pitch of the louver group 3a in the windward louver group 3a are 15 mm, and there are 15 louvers 3 and the width of the louver 3 in the leeward louver group 3b. The louver pitch is 1.6 mm, and the louver 3 is nine. The cut-and-raised angle α of each louver in the windward louver group 3a is 26 degrees, and the cut-and-raised angle β of each louver in the leeward louver group is 14 degrees. Further, the amplitude A of the fin is 6.5 mm, the length of the major axis of the cross section of the flat tube 1 is 16 mm, and the length of the minor axis is 1.4 mm.
[0013]
And if fin width B becomes longer than the above, the number of louvers will increase accordingly. At the same time, the length of the long axis of the cross section of the flat tube is increased or the number of flat tubes is increased. However, in any case, the number of leeward louver groups and the number of leeward louver groups are one by one.
In each of the examples of FIGS. 1, 3 and 4, the louvers and others are formed in accordance with FIGS.
[0014]
Next, FIG. 3 shows a third embodiment of the present invention. The difference between this embodiment and that of FIG. 1 is that the return louver 4 is located upstream of the center of the corrugated fin 2 in the width direction. The group width L1 of the leeward louver group 3a is shorter than the group width L2 of the leeward louver group 3b. Others are the same as FIG.
Next, FIG. 4 shows a fourth embodiment of the present invention. In this example, the return louver 4 is located downstream of the center in the width direction of the corrugated fin 2 and the windward side is opposite to that of FIG. The group width L1 of the louver group 3a is formed larger than the group width L2 of the leeward louver group 3b, and the others are the same as in FIG.
[0015]
【Example】
In the example of FIG. 1, the air flow direction (fin width B) of the corrugated fins 2 is 48 mm, and the cut-and-raised angle α of all the louvers 3 in the windward louver group 3a is 26 degrees. The louvers 3 in the leeward louver group 3b are all 11 degrees and corrugated fin type heat exchanges having six kinds of fins at each inclination angle of 14, 17, 17, 19, 21, and 23 degrees. A vessel was prepared. Further, as a comparative example, the corrugated fin 2 shown in FIG. 12 is configured such that the cut-and-raised angles α of the louver 3 of the leeward louver group 3a and the louver 3 of the leeward louver group 3b are both 26 degrees, and the others are all the same. A corrugated fin-type heat exchanger with the following conditions was prepared. Then, heat dissipation performance and pressure loss of the heat exchanger of the comparative example and the heat exchanger of each cut-and-raised angle β of FIG. 1 were measured in a wind tunnel under a wind speed of 4 m / sec.
[0016]
The experimental results are shown in FIG. In the figure, STD present at the left end is a heat exchanger using the conventional corrugated fin shown in FIG. 12, which is a pressure loss and a heat radiation performance when the wind speed is 4 m / sec. And In comparison with this, the pressure loss and the heat radiation performance of six types of heat exchangers each having the cut-and-raised angle β of each louver in the leeward louver group 3b are compared.
[0017]
The following becomes clear from the results of FIG.
Each heat exchanger in which the cut-and-raised angle β of each louver 3 of the leeward louver group 3b is in the range of 17 degrees to 23 degrees has the same or approximately the same heat dissipation performance as that of the conventional type (STD), The pressure loss of the air flow is reduced by about 3% to 8%. This means that when each of these heat exchangers is actually mounted in the engine room as an automotive heat exchanger, the wind speed that circulates through the heat exchanger is increased compared to the conventional heat exchanger of the comparative example. Means. As a result, the heat dissipation performance of the heat exchanger can be improved as the wind speed increases.
[0018]
That is, according to the experimental result of FIG. 8, since the heat dissipation performance is almost the same and the ventilation resistance is reduced by about 3% to 8%, the ventilation performance of the heat exchanger in the vehicle mounted state is improved accordingly, It can be seen that the wind speed increases accordingly and the heat dissipation performance improves.
In the heat exchanger in which the cut-and-raised angle β of each louver 3 in the leeward louver group 3b is 14 degrees, the heat radiation performance is reduced by about 7% compared to that of the conventional type, but the pressure loss is about 16% more than that. Decrease in pressure loss more than deterioration in heat dissipation performance. Thereby, the heat exchanger at the time of mounting in a vehicle can further improve the ventilation, and based on that, the flow rate of the air flow through the heat exchanger can be increased to obtain a heat exchange performance higher than that of the conventional heat exchanger. .
Similarly, even in a heat exchanger in which the cut-and-raised angle β of each louver 3 in the leeward louver group 3b is 11 degrees, the pressure loss is lower than the heat dissipation performance compared with the conventional heat exchanger. When the exchanger is mounted on a car, the overall heat exchange performance can be expected to be higher than conventional.
[0019]
Next, FIG. 9 is a comparison between each heat exchanger using the corrugated fins 2 of FIG. 2 and a conventional heat exchanger, and the fin width B of each heat exchanger is a comparative example. 2 is set to be 26 degrees as in the case of FIG. 1 and the cut angle of each louver 3 of the leeward louver group 3b is cut. Production of heat exchangers of 11 degrees and 14 degrees, 17 degrees, 19 degrees, 21 degrees, and 23 degrees, respectively, and compared them with conventional heat exchangers It is.
[0020]
In the conventional heat exchanger (STD), the cut-and-raised angle of each louver 3 of the leeward louver group 3a and the cut-and-raised angle of each louver 3 of the leeward louver group 3b are 26 degrees as in FIG. In the wind tunnel, the wind speed was 4 m / sec. As a result, although the heat radiation performance is reduced by about several percent as compared with each heat exchanger in the case of FIG. 8, the pressure loss is further reduced by about 5% as compared with the heat exchanger of FIG.
As a result, it can be seen that, when this heat exchanger is mounted on an actual vehicle, the flow rate is greatly increased and the heat exchange performance is improved as a whole when the heat exchanger is mounted on an actual vehicle.
[0021]
Next, FIG. 10 shows each heat exchanger using the corrugated fins 2 of FIG. 3, which is the ratio of the group width L1 of the leeward louver group 3a to the group width L2 of the leeward louver group 3b, the group width L1 / group. In the case where the ratio of the width L2 is 0.8, the wind speed was set to 2 m / sec in the wind tunnel experiment, and the same experiment as FIG. 8 was performed. This heat exchanger is used under conditions where the wind speed is not so high, and the pressure loss is reduced as much as possible. Next, FIG. 11 uses the corrugated fin 2 of FIG. 4, and when the ratio, group width L1 / group width L2 is 1.2, the wind speed is set to 6 m / sec and the same as FIG. The experiment was conducted. This heat exchanger is used under conditions where the wind speed can be increased, and aims to improve the heat dissipation performance on the windward side as much as possible.
[0022]
The results of FIGS. 10 and 11 also obtain the same actions and effects as in FIG.
Further, in the above experimental example, the thickness of the radiator was fixed to 48 mm, but it was set to 24 mm and 36 mm, and other conditions were the same even when the same experiment was performed in FIGS. The result was obvious.
Furthermore, in the above experiment, the windward louver angle and the conventional louver angle were fixed at 26 degrees, respectively, but the same results were obtained when they were set at 24 degrees, 28 degrees, and 30 degrees.
[0023]
[Operation and effect of the invention]
According to the corrugated fin type heat exchanger according to claim 1, cut-and-raised angle of the louver 3 of all leeward louver group 3b with respect to the return louver 4 located in the middle portion β are all windward louver group 3a is formed to be smaller than the cut-and-raised angle α, the air resistance of all the leeward louver groups 3b in which the heat dissipation amount is reduced is reduced, and the overall air circulation speed is increased by that amount, resulting in the heat dissipation amount. Can be increased.
[0024]
According to the corrugated fin heat exchanger according to claim 2, the louver width S2 of the louver 3 of the leeward louver group 3b is formed larger than the louver width S1 of the leeward louver group 3a. By reducing the number of cuts on the leeward side, the air resistance of the leeward louver group 3b can be further reduced, the air circulation speed can be increased, and the heat radiation amount can be increased.
According to the corrugated fin type heat exchanger according to claim 3, the group width L2 which is the width of the entire leeward louver group 3b is formed larger than the group width L1 of the leeward louver group 3a. Therefore, in a heat exchanger in which the flow rate of the air flow must be relatively small, the air resistance on the leeward side can be greatly reduced, and as a result, the amount of heat radiation can be maximized.
[0025]
According to the corrugated fin heat exchanger according to claim 4, the group width L2, which is the entire width of the leeward louver group 3b, is formed smaller than the group width L1 of the leeward louver group 3a. , In which the flow rate of air flowing through the heat exchanger can be made relatively fast, increase the number of louvers in the leeward louver group and maximize the heat radiation in that part, and the flow resistance of the leeward louver group And as a result, the overall heat exchange amount can be increased.
According to the corrugated fin heat exchanger according to claim 5, the cut-and-raised angle α of the louver 3 of the leeward louver group 3a, the cut-and-raised angle β of the leeward louver group 3b, and the fin width B in the air flow direction. Since it is in a specific range, it is possible to provide a product with better heat dissipation performance.
[Brief description of the drawings]
FIG. 1 is a longitudinal cross-sectional explanatory view of a main part of a corrugated fin heat exchanger showing a first embodiment of the present invention, and is a schematic cross-sectional view taken along line II in FIG.
FIG. 2 is a longitudinal sectional explanatory view of a main part of a corrugated fin type heat exchanger showing a second embodiment of the present invention, cut along the same plane as FIG.
FIG. 3 is a longitudinal cross-sectional explanatory view of a main part of a corrugated fin type heat exchanger showing a third embodiment of the present invention, cut along the same plane as FIG. 1;
FIG. 4 is a longitudinal sectional explanatory view of a main part of a corrugated fin type heat exchanger showing a fourth embodiment of the present invention, cut along the same plane as FIG.
FIG. 5 is a perspective view of an essential part of a corrugated fin heat exchanger according to the present invention.
6 is a cross-sectional view of the main part showing details of the corrugated fin heat exchanger in the embodiment of FIG. 2;
FIG. 7 is a schematic view taken along the line VII-VII.
8 is a comparison diagram of heat radiation performance and pressure loss for a heat exchanger of each leeward louver angle using the corrugated fin in FIG. 1. FIG.
9 is a comparison diagram of heat radiation performance and pressure loss for a heat exchanger of each leeward louver angle using the corrugated fin in FIG. 2. FIG.
10 is a comparison diagram of heat radiation performance and pressure loss for a heat exchanger of each leeward louver angle using the corrugated fin in FIG. 3. FIG.
11 is a comparison diagram of heat radiation performance and pressure loss for a heat exchanger of each leeward louver angle using the corrugated fins in FIG. 4. FIG.
FIG. 12 is a longitudinal sectional explanatory view of a main part of a conventional corrugated fin type heat exchanger.
FIG. 13 is a measurement diagram showing the difference between the fin surface temperature at each position in the air flow direction of the corrugated fin and the temperature of the air flow 5;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flat tube 2 Corrugated fin 3 Louver 3a Upwind louver group 3b Downwind louver group 4 Return louver 5 Air flow S1, S2 Louver width L1, L2 Group width A Amplitude B Fin width F Fin pitch

Claims (5)

A number of flat tubes (1) arranged at regular intervals;
Located between the adjacent flat tubes (1), the long axis direction of the cross section of the flat tube (1) coincides with the width direction, and the top and valley portions at both ends of the wave amplitude direction are flat tubes ( A number of corrugated fins (2) fixed to the outer surface of 1),
In the corrugated fin type heat exchanger in which the air flow (5) flows in the long axis direction of the flat tube (1),
In the corrugated fin (2), a large number of louvers (3) are formed obliquely spaced apart from each other in the width direction, and a return louver (4) is disposed in the middle, and the return louver The only leeward louver group (3a) located upstream of the air flow (5) and the only leeward louver group (3b) located downstream of the air flow (5) via The cutting and raising direction of (3) is formed in reverse,
Corrugated fin type heat exchanger in which the cut-and-raised angle β of each louver (3) of all leeward louver groups (3b) is smaller than the cut-and-raised angle α of all louver groups (3a) on the leeward side . In claim 1,
A corrugated fin heat exchanger in which the louver width (S2) of each louver (3) of the leeward louver group (3b) is formed larger than the louver width (S1) of the leeward louver group (3a). In claim 1,
A corrugated fin heat exchanger in which the group width (L2), which is the entire width of the leeward louver group (3b), is formed larger than the group width (L1) of the leeward louver group (3a). In claim 1,
A corrugated fin heat exchanger in which the group width (L2), which is the entire width of the leeward louver group (3b), is smaller than the group width (L1) of the leeward louver group (3a). In any one of Claims 1-4,
The cut-and-raised angle α of each louver (3) in the leeward louver group (3a) is 24 to 30 degrees, and the cut-and-raised angle β of each louver (3) in the leeward louver group (3b) is 11 to 23 degrees. A corrugated fin-type heat exchanger in which the corrugated fin (2) has a fin width B in the air flow direction of 24 mm to 64 mm.

Images