JPS6231273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a finned tube heat exchanger used in air conditioners and the like.

BACKGROUND ART Conventionally, a finned tube heat exchanger as shown in FIG. 1 has been used as a heat exchanger in an air conditioner or the like. That is, the fins 1a are arranged in parallel at predetermined intervals to form a flat plate fin group 1, and the heat exchanger tubes 2 are inserted in multiple stages at right angles to the flat plate fin group 1. The air flows in the direction of the arrow between the flat fins 1a and exchanges heat with the refrigerant in the conduction pipe 2.

However, the thickness of the temperature boundary layer 3 on the heat transfer surface of the flat fin 1a of the heat exchanger having such a configuration is as follows.
As shown in Figure 2, the heat transfer coefficient increases in proportion to the square root of the distance from the air inlet, so the farther away from the air inlet, the air side heat transfer rate decreases significantly, and the heat transfer coefficient as a heat exchanger decreases. It had the disadvantage of low performance. In addition, when this conventional heat exchanger is used as an evaporator, the fin 1 near the heat exchanger tube 2
Water droplets that condense on the surface a do not fall immediately and remain accumulated on the surface of the fin 1a, which increases air ventilation resistance and further deteriorates heat transfer performance.

The present invention solves the above-mentioned conventional drawbacks,
The purpose is to significantly improve the heat transfer coefficient on the air side heat transfer surface, and also to improve the drainage of water droplets that condense on the fin surface near the heat transfer tubes when the heat exchanger is used as an evaporator. be.

Hereinafter, the present invention will be explained with reference to FIGS. 3 and 4 of the accompanying drawings showing one embodiment thereof. Here, the heat exchanger of the present invention basically has the same configuration as the conventional one, except that the structure of the fins is different.

In FIG. 3, the flat plate fin 1a has a fin collar portion 1b which is barred at regular intervals, and a heat transfer tube 2 is inserted into the fin collar portion 1b, and the heat transfer tube 2 is inserted in the direction perpendicular to the air flowing in the direction of the arrow. Heat exchanger tubes 2 adjacent in the step direction of the heat tubes 2
An uneven strip 4 is provided between the heat exchanger tubes 2 along a straight line connecting the heat exchanger tubes 2 in the step direction, and a plurality of cut-outs 5, 6, 7, and 8 are provided on the left and right sides thereof.

Parts 5, 6 of these cut-outs 5, 6, 7, 8 are arranged to have a constant inclination degree and direction with respect to the surface of the flat plate fin 1a, to the left and right with the uneven strip 4 as a boundary, as shown in FIG. It is cut and raised on the front and back surfaces of the flat plate fin 1a. The remaining cut-outs 7 and 8 are cut and raised alternately on one side of the flat plate fin 1a so as to have the same inclination and direction as the cut-outs 5 and 6 with respect to the flat plate fin 1 side. Also, cut and raise 5, 6,
7, 8 are openings 9, 10, 1 that are open in the ventilation direction on both the front and back sides of the flat plate fin 1a or on either one side.
1, 12.

In the above configuration, the uneven strips 4 are provided on the flat plate fin 1a.
Since the flat plate fins 1a have short fins (heat exchange pieces) lined up in the air flow direction, the uneven strips 4 and the cut-outs 5, 6, 8 are provided. The thickness of the temperature boundary layer formed on each of the fins 7 and 8 is thin, and the air flows from the back side of the fin to the front side through the openings 9, 10, 11, and 12, promoting mixing and turbulence of the air flow. Moreover, since the air flow is disturbed by the uneven strips 4, the heat transfer performance is greatly improved.

Furthermore, when this heat exchanger is used as an evaporator, the condensed water generated near the heat exchanger tubes 2 on the surface of the flat plate fins 1a is accelerated to fall due to the capillary phenomenon of the uneven strips 4, so that water drains easily. will improve.
As a result, the openings 9 of the cut-outs 5, 6, 7, 8,
10, 11, and 12 are not blocked by condensed water, and the cut-outs 5, 6, 7, and 8 can maintain the effect of reducing the thickness of the temperature boundary layer for a long time. can.

As is clear from the above embodiments, the finned tube heat exchanger of the present invention has an uneven strip extending in the step direction of the heat transfer tube group in the mutual gap in the step direction of the heat transfer tube group in each fin of the fin group. and further provided with a plurality of cutouts opening in the air flow direction on both sides of the uneven strip so as to have the same inclination and direction with respect to the front and back surfaces of the fin,
In the air flow, the thickness of the temperature boundary layer is reduced and the mixing and turbulence of the flowing air is promoted, so the air side heat transfer coefficient is significantly improved, and even when this heat exchanger is used as an evaporator, Since the uneven stripes improve the drainage of water droplets near the heat transfer tube, it has various effects such as good ventilation over a long period of time and improved heat exchange performance.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional finned tube heat exchanger, Fig. 2 is a thermal fluid characteristic diagram of the same heat exchanger, and Fig. 3 is a finned tube heat exchanger according to an embodiment of the present invention. FIG. 4 is a sectional view of the main part of the heat exchanger taken along line A--A in FIG. 3. 1a... Flat plate fin, 1b... Fin collar portion, 2... Heat exchanger tube, 4... Uneven strip, 5, 6, 7,
8...Cut up.

Claims (1)

[Claims] 1. A fin group consisting of a large number of fins arranged in parallel at predetermined intervals and through which air flows;
A finned tube heat exchanger is constituted by a group of heat transfer tubes which are inserted perpendicularly into the group of fins and through which a refrigerant passes, and each fin of the group of fins has a plurality of heat transfer tubes inserted in the group at right angles. An uneven strip extending in the direction of the steps of the heat transfer tube group is provided in the gap, and a plurality of cutouts opening in the air flow direction on both sides of the uneven strip are provided with the same inclination and angle with respect to the front and back surfaces of the fins. Tube heat exchanger with fins installed in the same direction.