JPH0331693A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To improve the dropping of water drops, condensed on an outer surface, and prevent the increase of the ventilating resistance of air stream as well as the deterioration of heat transfer efficiency by a method wherein a water discharging surface, communicating the direction of the stage of flat plate fins linearly, is provided between a front rim side flat groove and a rear rim side flat groove on the flat plate fin while upstream side flat tubes and downstream side flat tubes arc arranged io zigzag. CONSTITUTION:In a plurality of flat plate fins 9, upstream side flat tubes 14 and downstream side flat tubes 15 are inserted into and contacted with front rim side and rear rim side flat grooves 10, 11, formed by notching the front rim side and the rear rim side of the flat plate fins 9 in the direction of air stream A, while the flat tubes 14, 15 are arranged in zigzag whereby the development of the temperature boundary layer of the air stream A is restricted and the improvement of heat transfer efficiency between the air stream A and the upstream side flat tubes 14 as well as the downstream side flat tubes 15 is contrived. When the finned heat exchanger is used as an evaporator and water drips L are condensed on the outer surface thereof, the water drips, stagnating on the upper surfaces of the upstream side flat tubes 14 and the downstream side flat tubes 15, can be dropped along a water discharging surface 12, communicated linearly in the direction of the stages, whereby the dropping of the water drips may be improved and the increase of the ventilating resistance of the air stream A as well as the deterioration of the heat transfer efficiency may be restrained.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a finned heat exchanger that is used in air conditioners, refrigeration equipment, automobile equipment, etc., and transfers heat between fluids such as refrigerant and air. .

Conventional technology In recent years, finned heat exchangers have been required to be made more compact in terms of equipment design, and as shown in Japanese Patent Application Laid-Open No. 116291/1983, improvements in the fin shape and tube inner surface shape have been made. Efforts are being made to improve efficiency.

Hereinafter, the conventional finned heat exchanger mentioned above will be explained with reference to the drawings.

8 and 9 show the shape of a conventional finned heat exchanger, FIG. 10 shows the shape of the fins constituting the conventional finned heat exchanger, and FIG. 11 shows the cross-sectional shape of a flat tube. 8 to 11, reference numeral 1 denotes wave-shaped fins bent in a wave shape and arranged in parallel at a constant fin pitch Pf, and provided with bent portions 2 at both ends and louvers 3 divided in the air inflow direction. .

Reference numeral 4 denotes a flat tube that is closely attached to the bent portions 2 at both the upper and lower ends of the corrugated tube 1, and is composed of a long side 5, a short side 6, and a dividing plate 7 that divides the inside of the tube, with the long side 5 facing in the airflow direction A. A plurality of stages are provided in the horizontal direction with a stage pitch Pd so as to be substantially parallel to each other. 8 is a header connected to both ends of the flat tube 4, and together with the flat tube 4 constitutes an internal flow path for the refrigerant R.

The structure configured as above is shown below in Figure 12 and Figure 1.
The operation will be explained using FIG.

Heat exchange is performed between the airflow A flowing between the corrugated fins 1 and the refrigerant R flowing within the flat tube 4 through the corrugated fins 1 and the flat tube 4. At this time, since the looper 3 is divided and provided on the surface of the corrugated fin 1, the development of the temperature boundary layer of the air flow A generated on the surface of the corrugated fin 1 is suppressed, and the air mA
The heat transfer coefficient between the corrugated fins 1 and the corrugated fins 1 is improved. Moreover, the inside of the flat tube 4 is made into a microchannel by the dividing plate 7, and the heat transfer coefficient between the flat tube 4 and the refrigerant R is also improved.

Problems to be Solved by the Invention However, in the above configuration, a temperature boundary layer of air inflow develops on the downstream side of the flat tube 4 with respect to the air IA, so the heat transfer coefficient decreases, and this finned heat The exchanger is used as an evaporator and water droplets condense on the outer surface. In this case, as shown in FIG.
Not only do water droplets accumulate inside the fins, but also because the corrugated fins 1 of each stage are separated by the flat tubes 4, the water droplets that travel down the surface of the corrugated fins 1 are difficult to fall to the lower stage, and the flat pipes Since the air accumulates on the upper surface of the tube 4 and causes an increase in the ventilation resistance of the air flow, there is a problem that heat transfer between the corrugated fins 1 and the air flow A is also inhibited.

In view of the above problems, the present invention aims to improve the heat transfer coefficient of a flat tube, and also improves the falling of water droplets even when this finned heat exchanger is used as an evaporator and water droplets condense on the outer surface. This suppresses increases in airflow resistance and decreases in heat transfer coefficient.

Means for Solving the Problems In order to solve the above problems, the heat exchanger with fins of the present invention includes a flat plate fin having a plurality of flat grooves on the front and rear edges in the airflow direction, and a flat plate fin inserted into the flat groove on the front edge side of the flat plate fin. and a downstream flat tube inserted into the flat groove on the trailing edge of the flat fin. In addition to providing a drainage surface that runs through the drain, the upstream flat pipe and the downstream flat pipe are arranged in a staggered manner.

Effect The present invention has the above-described configuration to improve the heat transfer coefficient in the downstream part of the flat tube, and even when water droplets condense on the outer surface of the finned heat exchanger when used as an evaporator, they do not accumulate on the upper surface of the flat tube. Since the collected water droplets can fall to the lower stage through the drainage surface communicating in the direction of the stage, it is possible to improve the falling of the water droplets and suppress the increase in the ventilation resistance of the airflow and the decrease in the heat transfer coefficient.

EXAMPLE Hereinafter, a finned heat exchanger according to an example of the present invention will be described with reference to the drawings.

1 and 2 show the shape of a finned heat exchanger in an embodiment of the present invention, and FIG. 8 shows the shape of a flat fin,
FIG. 4 shows the cross-sectional shape of the flat tube.

In Figures 1 to 4, 9 is a constant fin pitch P
A plurality of flat plate fins arranged in parallel at f have a leading edge side flat groove 10 formed by cutting out the leading edge side in the airflow A direction, a trailing edge side flat groove 11 formed by cutting out the trailing edge side, and a leading edge side flat groove 11 formed by cutting out the trailing edge side. A drainage surface 12 having a width W is provided between the groove 10 and the flat groove 11 on the trailing edge side, and the drainage surface 12 has a width W and communicates linearly with the step direction of the flat plate fin 9. Further, on the surface of the flat fin 9, a louver 13 is also provided, which is obtained by dividing the flat fin 9 in the direction of the airflow A. 14
15 is a flat tube on the upstream side that is inserted into the flat groove 10 on the front edge side of the flat plate fin 9, and 15 is the flat groove 11 on the rear edge side of the flat plate fin 9.
The downstream flat tube 14 is inserted into the downstream flat tube 14,
The downstream flat pipes 15 are arranged in a staggered manner. Further, the upstream flat tube 14 and the downstream flat tube 15 are composed of a long side 16, a short side 17, and a dividing plate 18 that divides the inside of the tube, and the long side 16 is provided in a plurality of stages with a step pitch Pd. A header 19 is connected to both ends of the upstream flat tube 14 and the downstream flat tube 15, and together with the upstream flat tube 14 and the downstream flat tube 15, constitutes an internal flow path for the refrigerant.

The operation of the finned heat exchanger constructed as above will be described below with reference to FIGS. 5 and 6.

The air flowing between the flat plate fins 9 and the refrigerant R flowing through the ladder 19 into the upstream flat tube 14 and the downstream flat tube 15 are connected to the flat plate fins 9, the upstream flat tube 14, and the downstream flat tube 15. Heat exchange takes place via. At this time, since the louver 13 is provided on the surface of the flat fin 9, the development of a temperature boundary layer of the airflow A generated on the surface of the flat fin 9 is suppressed, and the heat transfer coefficient between the airflow A and the flat fin 9 is reduced. Improvements are being made. Furthermore, by dividing the flat tube into the upstream side upstream flat tube 14 and the downstream side flat tube 15 and piping them in a staggered manner, the development of the temperature boundary layer of the airflow A can be suppressed, and the airflow A and the upstream side flat tube The heat transfer coefficient between the tube 14 and the downstream flat tube 15 is improved. In addition, the upstream flat tube 14
The inside of the downstream flat tube 15 is made into microchannels by the dividing plate 18, and the heat transfer coefficient between the upstream flat tube 14, the downstream flat tube 15, and the refrigerant R is improved.

Also, when this finned heat exchanger is used as an evaporator and water droplets condense on the outer surface, as shown in FIG. The accumulated water droplets can fall to the lower stage through the drainage surface 12 that communicates linearly in the direction of the stage, so that the water droplets can fall smoothly, increasing the ventilation resistance of air mA and decreasing the heat transfer coefficient. can be suppressed.

As described above, according to this embodiment, the flat plate fin 9 has a plurality of stages of the leading edge flat groove 10 and the trailing edge flat groove 11 formed by cutting out the rear edge on the leading edge in the airflow direction, and the flat plate fin 9. The upstream flat tube 1 inserted from the side into the front edge side flat groove 10 of
4 and a downstream flat tube 15 inserted from the side into the flat groove 11 on the rear edge side of the flat plate fin 9. By providing the drainage surface 12 that communicates in a straight line, and by arranging the upstream aS flat pipe 14 and the downstream flat pipe 15 in a staggered manner, the development of the temperature boundary layer of the airflow can be suppressed, so that the airflow A and the upstream side In addition to improving the heat transfer coefficient between the flat tube 14 and the downstream flat tube 15, this finned heat exchanger is used as an evaporator, and even if water droplets condense on the outer surface, the drainage water that communicates in the direction of the stages can be improved. Since the water droplets can be allowed to fall to the lower stage along the surface 12, it is possible to improve the falling of water droplets and to suppress an increase in the ventilation resistance of the airflow A and a decrease in the heat transfer coefficient.

Effects of the Invention As described above, the present invention provides a flat plate fin having multiple stages of flat grooves on the front and rear edges in the airflow direction, a downstream flat tube inserted from the side into the flat groove on the front edge side of the flat plate fin, and a flat plate fin. It consists of a downstream flat tube inserted into the trailing edge II flat groove from the side, and a drainage surface is provided between the leading edge side flat groove and the trailing edge side flat groove of the flat plate fin to communicate the step direction of the flat plate fin with the straight groove. By arranging the upstream and downstream flat tubes in a staggered manner, the development of a temperature boundary layer in the airflow can be suppressed, improving the heat transfer coefficient between the airflow and the flat tubes. Even when the heat exchanger is used as an evaporator and water droplets condense on the outer surface, the water droplets that accumulate on the upper surface of the flat tube can travel through the drainage surface that communicates with the tiers and fall to the lower tier. By improving the falling of water droplets, it is possible to suppress an increase in airflow resistance and a decrease in heat transfer coefficient.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the shape of a finned heat exchanger in an embodiment of the present invention, Fig. 2 is a perspective view of the main part of Fig. 1, and Fig. 3 is a plan view showing the shape of the flat plate fin in Fig. 1. Figure 4 is a cross-sectional view showing the shape of the flat tube in Figure 1, Figure 5 is a cross-sectional view showing the flow state of airflow in the operating condition of Figure 1, and Figure 6 is a cross-sectional view showing the refrigerant circuit in Figure 1. 7 is a sectional view showing the water droplet adhesion situation in FIG. 1, FIG. 8 is a perspective view showing the shape of a conventional finned heat exchanger, and FIG. 9 is a perspective view of the main part of FIG. 8. ,
Fig. 10 is a plan view showing the shape of the corrugated fin shown in Fig. 8, Fig. 11 is a sectional view showing the shape of the flat tube shown in Fig. 8, and Fig. 12 shows the flow state of the airflow in the operating state shown in Fig. 8. 13 is a perspective view showing the refrigerant circuit in FIG. 8, and FIG.
The figure is a sectional view showing the state of water droplet adhesion in FIG. 8. 9... Flat plate fin, 10... Front edge side flat groove, 11.
...Flat groove on the trailing edge side, 12...Drainage surface, 14...Flat pipe on the upstream side, 15...Flat pipe on the downstream side.

Claims (1)

[Claims] A flat plate fin having multiple stages of flat grooves on the front and rear edges in the airflow direction, an upstream flat tube inserted into the flat groove on the leading edge side of the flat plate fin, and a downstream flat tube inserted into the flat groove on the trailing edge side of the flat plate fin. A drainage surface is provided between the leading edge side flat groove and the trailing edge side flat groove of the flat plate fin, and a drainage surface is provided that communicates the flat plate fin step direction in a straight line, and the upstream side flat tube and the downstream side flat tube are arranged in a staggered manner. A finned heat exchanger characterized by piping.