JPS59212693A - Heat conducting fin - Google Patents

Abstract

PURPOSE:To improve the heat conducting performance of a fin in a corrugated heat conducting fin by setting the louver spacing/fin pitch and the louver slanting angle to a predetermined value respectively. CONSTITUTION:By bending the fin material which has multiple cutouts 10 that are directed perpendicularly to the flowing air and staggered like a stair case when viewed from an end at a bending area 9, corrugated fins are continuously formed. Since the cutouts 10 are staggered like a stair case that forms respective louvers 5, a gap 11 is formed between the louvers, and the edges of the respective louvers are directed in the same direction. Respective louvers are facing with each other with a matching stair case-like staggerings. The length of the cutout L1 is L0 between hair pins 7, 7'. The ratio of the louver spacing (l) and the fin pitch Pf is set to be 0.2-0.6, and the louver slanting angle to be 5-43 deg.. Thus, the cutout can be made as large as possible, the accuracy of the gap between the louvers can be secured, and the heat conducting performance of the fin can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to the shape of corrugated fins in a heat exchanger consisting of flat heat transfer tubes and corrugated fins used in air conditioners, refrigerators, etc.

[Background of the invention]

An example of a conventional corrugated heat transfer fin that is considered to be closest to the present invention is shown in FIG. This example shows multiple cuts 1
. The structure is such that it can be bent in a dogleg shape. 3 is a flat heat exchanger tube. However, since corrugated fins are originally made from a continuous long ribbon, depending on the size of the heat exchanger, the work of first bending them into a dogleg shape from around the center is actually extremely low in productivity. , there may be a problem that dimensional accuracy is difficult to achieve. Second, when bending the center of the corrugated fin into a dogleg shape, one side is stretched and the other side is compressed, so the excess material on the compressed side is compressed into the hairpin section. It is thought that it will stand out. In such a case,
If the flatness of the hairpin portion is poor, there is a concern that a serious problem may arise in that the smooth connection with the heat exchanger tube 3 is hindered. As described above, the conventional example has many problems when it is actually implemented.

[Purpose of the invention]

An object of the present invention is to improve the heat transfer performance of the fins by increasing the length of the louvers, that is, the strips formed by the cuts, and by improving the arrangement of the louvers.

[Summary of the invention]

In order to improve the performance of corrugated heat transfer fins, the shape and arrangement of the louvers are important, as well as making the louver cut length as long as possible.

The feature of the present invention is that the louver gap/fin pitch is 0.2
~0.61 The feature is that the angle B of the lubba peak is 5° to 43°.

[Embodiments of the invention]

Examples of the present invention will be described below. First, 1 of the present invention
The configuration of the embodiment will be explained with reference to FIGS. 3 to 8. FIG. 3 shows a developed view of the heat transfer fin according to the present invention. This fin has a large number of cuts 9 in a direction substantially perpendicular to the incoming air 4 (the longitudinal direction of the fin), and these cuts are provided so that the positions of the ends of the cuts are staggered. Further, the large number of louvers 5 formed by the cuts are formed at an obtuse angle with a ridgeline 6 at the center along the longitudinal direction. The louver 5 and the hairpin part 7.7' are connected by an inclined part 8 formed at both ends of the louver.

FIG. 4 shows a sectional view taken along line I-1 in FIG. 3. The protruding direction of the ridge line 6 of the louver is changed for each block so that when the fin is bent to form a corrugated shape, it will be in the same direction. FIG. 5 is a cross-sectional view taken along the line ■-■ in FIG.
In this block, each louver has a Δ-shaped cross section. On the other hand, FIG. 6 is a sectional view taken along the line -■ in FIG. 3, and the cross section of each louver in this flock is recessed in a V-shape. Next, FIG. 7 shows an external view when the bent portion 9 of FIG. 3 is bent to completely form corrugated heat transfer fins.

In FIG. 3, if the bending direction of the bending portion 9 is reversed at both ends of the louver, corrugated fins as shown in FIG. 7 can be formed continuously. Since the notches forming the louvers are staggered, the gaps 11 between the louvers are formed by simply bending the louvers as shown in FIG. The direction of the bending line of the bending part 9 and the notch 10 forming the louver are almost perpendicular to each other, so that the corrugated fin shown in FIG. 7 can be formed naturally without stretching or contracting the fin material. Shaped. FIG. 8 shows a sectional view (for one mountain) taken along the line ■-■ in FIG. 7, and as shown, the edges 6 of each louver are all in the same protruding direction.

The operation of this embodiment will be explained below. A corrugated heat transfer fin consisting of a group of minute louvers, the shape of the louvers is important for improving heat transfer performance.

The length L' of the cuts 10 forming the array and the louver. , the present embodiment has the following effect on the former. As shown in FIG. 8, which shows the fin cross section and the phase of the air flow between the fins, each louver does not move stepwise, so the air flow flows through the louver gap at approximately the same flow speed without being significantly bent. The delta-shaped louver cross section promotes the flow of air between the upper and lower strips. As a result, each louver is effectively utilized, greatly contributing to improving the heat transfer performance of the fins.

Regarding the latter, that is, the length Li of the notch 10 of the louver, it is important to make it as thick as possible in order to make the most of the effect of the louver. In this regard, as explained in FIG. 7, the length Ll of the cut 10 is set to the distance between the upper and lower hairpins 7.7'.

The configuration is such that it is equivalent to, that is, can be provided at maximum. As a result, the effect of each louver is maximized,
It plays an important role in greatly improving the heat transfer performance of the fins. By the way, with this type of heat transfer fin, the positioning of the bent portion 9 forming the hairpin portion 7 has often been a problem in the past. In the fin according to the present invention, as described above, each louver projects in a Δ shape, so that the positions of the bent ridges 8 at both ends can be determined extremely accurately.

As a result, the gap 11 between the valley louvers can reliably have a specific dimension.

As described above, the heat transfer fin according to the present invention has a shape that has extremely excellent heat transfer performance, and has a configuration with high manufacturing precision and excellent productivity.

FIG. 9 shows another embodiment of the invention. This example has three edges on each louver, 7 (12° 13.14)
In this example, the cross section taken along line V--■ in FIG. 9 has the shape shown in FIG. 10. This example also has the same effect as the previous example, but the position of the bent portion 9 is particularly clear 9, and an improvement in manufacturing accuracy can be expected.

Next, the performance characteristics of the heat exchanger according to the present invention will be specifically explained.

First, Fig. 11 shows the louver cutting rate r2L+/L.

X100 (%) and the increase rate of heat transfer coefficient are shown.

Experimental results show that when the cutting depth r of the louver is increased, the heat transfer coefficient increases almost proportionally. In the fin according to the present invention, as shown by the solid line, the louver cut length Ll can theoretically be made 100%, so the effect of the louver can be utilized to the maximum extent.

On the other hand, as shown by the broken line, in the conventional technique, the louver cutting depth r is at most 90%, and the rate of increase in the heat transfer coefficient remains as shown in the figure. Note that due to the difference in the shape of the louvers, the tendency of increase in the heat transfer coefficient depending on the louver cutting rate differs between the conventional heat exchanger and the heat exchanger according to the present invention.

Next, Figure 12 shows the distance between the upper and lower louvers/fin pitch (
=t/Pt> and the louver peak angle β0 (see Figure 8!@) are the results of a study on how they affect the heat exchange amount Q of the heat exchanger. As a matter of fact, all blowing power must be compared in a certain way. In the case of the fin of the heat exchanger according to the present invention, the louver peak angle β0 and the upper and lower louver spacing/
Due to the combination of fin pitch C=t/Pi), Q is the first
As shown in Figure 2, there are appropriate combinations for increasing Q. FIG. 13 shows the influence of the louver peak angle β0 and the upper and lower louver spacing/fin pitch, with the heat exchange amount Q plotted on the vertical axis. First, regarding the louver spacing, the appropriate range is louver spacing/fin pitch=0.2 to o, 6 (FIG. 13 ■), regardless of β0. On the other hand, the relationship between the louver peak angle β0 and the heat exchange amount Q is shown in Fig. 14 (upper and lower louver spacing/fin pitch = 0.4
in the case of). When β〉5°, the rate of increase in Q decreases, and β〉43
Q decreases significantly at °. Therefore, the appropriate range of β is 5°<β<43° (1 in FIG. 14).

Unfortunately, at 10°〈β〈38° (■ in Figure 14), Q
is the maximum, so this range can be said to be the most desirable range.

〔Effect of the invention〕

According to the present invention, in a corrugated heat transfer fin made of fine particles (louvers), the depth of cut can be maximized and the louver and louver cap KM degree can be secured, so the heat transfer performance of the fin is improved. Significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a partial view of a conventional heat transfer fin, FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a developed view of the fin of the first embodiment of the present invention, and FIG. Figure 5 is a cross-sectional view of Figure 3
Figure 6 is a sectional view taken along line 3, Figure 7 is an external view of the corrugated heat transfer fin according to the first embodiment of the present invention, Figure 8 is a sectional view taken along line IV-IV of Figure 7, and Figure 9 is a sectional view taken along line IV-IV of Figure 7. The fin development view of another embodiment of the present invention, the 1θ figure is a sectional view of FIG.
FIG. 4 is an explanatory diagram of the performance of the fin according to the embodiment of the present invention. 1.2...notch, 3...flat heat exchanger tube, 4...
Air inflow direction, 5...louver, 6...ridge line, 7...
・Hairpin part, 8... Inclined part, 9... Bent part, 10
...notch, 11... gap between strips. Figure 1 Figure 3 Figure '0-4 Rain 5 Figure 10 10 10 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] In corrugated heat transfer fins in which the fin plates are continuously bent in a hairpin shape, when the fins are stretched out to form a flat plate, a large number of cuts are made in the fin plate in the direction in which nitrogen air flows between the fins. , the positions of the ends of adjacent notches are shifted from each other, and the louver formed by the notch is formed at an obtuse angle with the ridge line at any point along the longitudinal direction, and the ends of all the louvers are bent. When a hairpin-shaped corrugated fin is made, the bend of the strip bending portion is almost perpendicular to the p-line and the direction of the cut, and the louver gap/fin pitch is 0.2 to 0.6.
A heat transfer fin characterized in that a louver projection angle B is in a range of 5° to 43°.