JPS59107190A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve a heat radiating characteristic, while realizing an inexpensive core of reduced diameter and weight, by employing specific values for the width, louver pitch and the angle of fin that lines in parallel to an air stream, in a corrugated fin type heat exchanger for a vehicle. CONSTITUTION:A corrugated fin 1b is molded by bending a brass or an aluminium sheet in the corrugated shape of sine curve. The flat plate portion of fin 1b is integrally formed with a number of louvers by cutting and raising transversely to the direction X of cooling air stream. In this case, a louver pitch Lw is preset in the range of 0.7-1.3mm., and a louver angle theta defined by cutting and raising is preset in the range of 32.5-40 deg. for realizing a reduction in dimension and weight. The width (c) of core is preset in the range of 10-20mm. which is advantageous from the viewpoint of heat radiating characteristic and air loss level. Furthermore, by presetting the louver angle theta in the range of 32.5-40 deg., a heat radiating efficiency, that is, the heat radiating capability of core can be improved. Besides, the smaller than louver pitch is, the more the number of louver blade is, the better the coefficient of overall heat transfer is. However, the louver pitch should be restricted to 0.7mm. for processing reasons.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger used as a heater core of an automobile radiator and an automobile heating system, and particularly relates to an improvement of corrugated fins constituting the core.

In a heat exchanger, such as an automobile radiator, a corrugated hu-in core that exchanges heat between engine coolant and cooling air is used to exchange coolant fluid in two or three rows in a direction parallel to the cooling air flow. A flat tube for circulation, a corrugated fin that is interposed between the flat tubes parallel to the air flow direction and has a width spanning the entire length of the tube arrangement, and an inlet and an outlet in which both ends of the flat tube are press-fitted, respectively, in a watertight manner. Each seat plate has an inlet and an outlet tank for cooling liquid.

The width and pitch of the corrugated fins used in conventional radiators of this type are relatively large in terms of heat dissipation performance and air resistance.
There is a problem in terms of weight reduction.However, in recent years, due to the miniaturization and weight reduction of automobiles and the installation of equipment to prevent exhaust gases, the space inside the gin room has become smaller, and as a result, the location of the radiator has become smaller. However, space is limited, and it is desired that the radiator be made thinner and lighter.

This invention was made to satisfy the above requirements, and the purpose is to provide a heat exchanger with corrugated fins that improves heat dissipation performance and enables a thinner core, lighter weight, and lower cost. do.

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show a case where the corrugated fin structure according to the present invention is applied to a heat exchanger, more specifically a radiator for an automobile.

In the figure, 1 is a corrugated fin-shaped core constituting a radiator, and the core 1 is in the direction of flow of cooling air
flat metal tubes 1α arranged in parallel with the flat tubes 1α, metal corrugated fins 71b interposed in contact between the flat tubes 1a and la, and an inlet in which the upper and lower ends of the flat tubes 1cL are respectively press-fitted and fixed in a watertight manner. and an exit side seat plate IC11d, and the entrance side seat plate I
C is attached with an inlet tank 2 that introduces the coolant from the water jacket of the engine (not shown), and the outlet side seat plate 1d collects the coolant that has passed through the flat tube 1cL of the core 1, and collects the coolant that has passed through the flat tube 1cL of the core 1. The outlet tank 3 that supplies water to the water jacket can be seen.

Further, the corrugated fin 1b- has a thickness of 0.05 to
It is made of 006 brass or aluminum plate bent into a sinusoidal wave shape, and the fin pitch Pf is about 1.7 TM1, and the wavy top of the fin 1b and the flat surface in contact with it. Cheap 14
and are integrated by soldering. Also, fin 1
As shown in FIG. 3, a large number of louvers 4 are cut and raised and integrally formed on the flat plate portion of b, perpendicular to the cooling air flow direction X, and the louver pitch LW at this time is 07 to 1. .3
trrrh, and the louver angle θ due to the cutting and raising is set to 325° to 40°. Still core 1
The width C is 10 to 20 mm, and the tube pitch PT is set in a range of 85 to 14 mm.

Next, the reason why the heat dissipation performance of the radiator can be improved and the radiator can be made thinner will be explained when the corrugated fins set to the above values are applied to the radiator.

Therefore, the dimensions of the core 1 shown in Fig. 1 were changed to tl = 610.
．． The effect on the heat dissipation performance of the O radiator was investigated when the width of the core 1, that is, the width C of the fin 1h was varied, with tz=360 fixed.

Figure 4 shows the thermal transmission coefficient K on the vertical axis and the thickness C of core 1 on the horizontal axis, and shows the measurement results for the thermal transmission coefficient when the thickness C of core 1 is changed. 3, where the louver angle θ = 28°, the louver pitch LW = 1.0, and the cooling air flow rate V a = 10 m/s.

Let the coolant flow rate G w = 120 t/min.

In this Figure 4, the characteristic curve I is the one when the height of the fin is 5 mm, the characteristic curve (■) is when the height of the fin is = 6-1, and the characteristic curve (■) is when the height of the fin is -7, and the core is 1. When the width C of the core 10 is gradually decreased, the heat flow rate increases, particularly when the width C of the core 10 is around 20 mm, it rises rapidly, and it is observed that it reaches the highest value around the width C of the core 101. This means that fin 1b
Louver angle θ, louver pitch Lw and fin height Hl
This means that if f is set to an appropriate value, the width C of the core 1 can be made thinner.

In addition, in Fig. 5, the core size is 610 x 360, the fin pitch P f "" is 1.7, the louver angle θ = 28°,
Louver pitch L W-1, Orim, cooling air flow rate ■α = 10 m/s, coolant flow rate G W: 1
201/min.

It shows the experimental results of the heat dissipation rate H and core thickness C of the radiator when the fin height Hf=7wn.

As is clear from the characteristic curve ■ in Figure 5, core 1
If the thickness C of the core 1 is gradually decreased, the heat dissipation area of the core 1 decreases, and the heat dissipation rate H also decreases in a quadratic curve, but the heat dissipation rate H is not proportional to the heat dissipation area. For example, when comparing the thickness C of core 1 with 16 mm and 13 mm, using the thickness of 16 mm as the standard, the heat dissipation area of core 1 of 13 + II m is 19% of that of core 1 with a thickness of 16 mm. However, as is clear from FIG. 4, since the heat transfer coefficient K is large, it is recognized that the actual heat dissipation rate decreases by only 15% corresponding to the increase.

In addition, in Figure 6, the core size is 610 x 360 degrees, fin pitch P f = 1.7 mm, louver angle θ = 28 degrees, louver pitch L w = 1.0 mm, and cooling air flow rate V.
a==10 m/s, coolant flow rate GW: 12
01/rn, in.

It shows the experimental results of the air loss ΔPα and the core thickness C of the radiator core when the fin height Hf=7 mm.

As is clear from the characteristic curve (■) in Fig. 6, when the thickness C of the core 1 is gradually reduced, the air loss △Pa decreases linearly, and the thinner the core 1 is, the more advantageous it is. Become. For example, when comparing the thickness C of core 1 with 16mm and 13cm, it is recognized that the air loss △Pa of the 13cm core can be reduced by 920% compared to that of 16mm, based on the thickness of 16mm. ing.

The above haluha angle θ-28°, louver pitch Lw = 10
This is the experimental result when the fin height Hf is 5~
Even if it changes to 7 mm, the core thickness should be kept at 10 to 20 rtrm.
It can be seen that setting the range is most advantageous in terms of heat dissipation performance and air loss.

As is clear from the measurement results in Figures 4 and 5 as described in Section 2, if the fin structure is set to the above-mentioned values,
The amount of heat transmission and the rate of heat dissipation are both necessary and sufficient, but as automobiles become smaller and lighter, thinner devices with even higher heat dissipation performance are desired.

Therefore, this invention sets one louver angle θ to 325° to 40°.
If it is set within this range, the heat dissipation rate, that is, the heat dissipation performance of the core can be improved. The reason for this will be explained below based on experimental results.

FIG. 7 shows the dimensions 11 of the core 1 shown in FIG. t2 is 268 m and 330 m, respectively, fin pitch P f = 1.1 rrrm, and fin height Hf - 7 m1
It shows the experimental results of the heat transmission coefficient and the louver angle θ when the cooling air flow velocity ■α=i 0 m/s.

In this FIG. 7, the characteristic curve ■ is louver pitch Lw=
08. The characteristic curve ■ is when the louver pitch L w = 10, and the characteristic curve ■ is when the louver pitch L w = 1.3. As the louver angle θ is gradually increased, the thermal transmission coefficient increases, and It was observed that the rate of rise suddenly increases when the louver angle θ is around 30°, and it becomes a steep rising curve until it reaches around 400°.Furthermore, FIG. i ■
, fin height Hf-7, cooling air flow rate V a =
Heat radiation rate H and louver angle θ when set to 10 m/s
This shows the experimental results. In the same figure, characteristic curve ■ is louver pitch Lw-08, characteristic curve X is louver pitch L w-1,0% characteristic curve X is louver pitch L
This is a characteristic diagram when w=13, and as is clear from these characteristic curves, when the louver angle θ is changed,
It is observed that the heat dissipation rate H increases rapidly when the louver angle θ is in the range from around 30° to around 40°.Furthermore, FIG.
Fin pitch P f-1,1% Fin height Hf=7
The relationship between the air loss △Pα and the louver angle θ when the shell and louver pitch L w = 1.0% and the cooling air flow velocity Va: 10 m/s is obtained from the experimental results, and from the same figure. As is clear from the above, when the louver angle θ is gradually increased, the core air loss ΔPcL increases rapidly when the louver angle θ is around 40°, and below that, the rate of change in the air loss ΔPa is relatively small and gradual. It was recognized that .

Therefore, it can be said from the experimental results shown in Figures 7 to 9 above that if the louver angle θ is set to 325° to 40°, the heat transfer coefficient K and the heat radiation rate H can be adjusted to the air loss Δpa. The louver angle θ can be increased without much influence, and this improves the heat dissipation performance of the core compared to a case where the louver angle θ is set to 30° or less, and makes it easier to make the core thinner.

Note that it has been theoretically proven that the smaller the louver pitch LW and the larger the number of louvers, the greater the heat mass flow rate K, and this tendency is shown in FIG.

This is also clear from Figure 8. However, the louver pitch LW
There are restrictions on current fin processing to reduce the size of 0.
The limit is about 7 Rui. Therefore, in order to further increase the heat transfer coefficient K, it is currently most effective and practical to set the louver angle θ to 325° to 40° as described in the present invention.

As described above, according to the present invention, in the corrugated 7-inch heat exchanger, the air flow parallel to the corrugated fin airflow,
The width C in the direction is 10 to 20 mm, and the louver pitch L of the corrugated fin is 07 to 13.
In addition, since the louver angle θ is set to 325° to 40°, the heat dissipation performance of the core can be significantly improved compared to a case where the louver angle is set to 30° or less without significantly increasing air resistance. This has the effect of further promoting thinning of the core, and also making it possible to reduce the weight and cost of the heat exchanger.

[Brief explanation of drawings]

Fig. 1 is a front view showing an example of a case where the heat exchanger according to the present invention is applied to a radiator, Fig. 2 is a perspective view showing a part of the core according to the invention, and Fig. 3 is a corrugated fin according to the invention. Cross-sectional views, Figures 4 to 6 are graphical representations of the experimental results of the nine inventions. Figure 4 is a characteristic diagram showing the relationship between heat transmission coefficient and core thickness, and Figure 5 is a graph showing the relationship between heat transfer coefficient and core thickness. A characteristic diagram showing the relationship between the core thickness and FIG. 6 is a characteristic diagram showing the relationship between the air loss and the core height. In addition, Figures 7 to 9 are graphical representations of experimental results in this invention, with Figure 7 being a characteristic diagram showing the relationship between heat transmission coefficient and louver angle, and Figure 8 being a characteristic diagram showing the relationship between heat transfer coefficient and louver angle. FIG. 9 is a characteristic diagram showing the relationship between air loss and louver angle. 1. Core, 1α...Flat tube, 1b. Corrugated fin, 1G, 1d... Seat plate, 2. Inlet tank.
3. Outlet tank, 4. Louver. Patent applicant: Japan Radiator Co., Ltd.
1. Nia, T-, 1, Agent Patent Attorney Fumi Furuya jJ%'
,"":j/9 and near' Figure 2 Figure 3 Figure 4 Core thickness C (1 point) Core lI-': ICC meeting)

Claims (1)

[Claims] In a corrugated fin type heat exchanger having a core, an inlet, and an outlet tank, the width C of the corrugated fin in the direction parallel to the air flow to the core is between 10 and 20, and the pinch Lw of the louver formed in the corrugated fin is
A heat exchanger characterized in that the angle θ of the louver is 32.5° to 40°.