JPH02309193A - heat exchanger with fins - Google Patents

Abstract

PURPOSE:To allow condensed water to easily drop by a method wherein drainage surfaces for intercommunicating flat plate fins in the direction of a stage are formed in the surfaces, on the downstream side of a flat groove, of the flat plate fins each having flat grooves formed in stages such that the front edge side in the direction of an air flow is notched, and louvers inclined in the direction of gravity from the upper stream side of an air flow to the down-stream side thereof are provided. CONSTITUTION:Drainage surfaces 9 for intercommunicating flat fins 7 in the direction of a stage are formed in the surface, on the downstream side of a flat groove 8, of the flat fin 7 having flat grooves 8 in stages formed such that the fron edge side in the direction of an air flow is notched. Louver 10 inclined in the direction of gravity from the upper streams side to the downstream side are provided. Thus, even when a heat exchanger with a fin is used as a vaporizer and water drops are condensed on an outer surface, water drops residing between the louvers 10 inclined in the direction of gravity from the upper stream side of an air flow to the downstream side thereof are influenced by an air flow and gravity and moved over the upper surface of a flat pipe 11 on the downstream side along the louvers 10. Thereafter, the water drops can drop to a lower stage along the drainage surfaces 9 for intercommunicating the flat fins in the direction of a stage. This constitution effects excellent drop of water drops and enable suppression of the increase of draft resistance of an air flow and lowering of the efficiency of heat transfer.

Description

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

BACKGROUND OF THE INVENTION In recent years, finned heat exchangers have been required to be more compact in terms of equipment design, and efforts have been made to improve efficiency by improving the fin shape and tube inner surface shape.

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

8 and 9 show the shape of a conventional finned heat exchanger, FIG. 10 shows the fin shape constituting the conventional finned heat exchanger, and FIG. 11 shows the flat tube shape. Figures 8 to 11
In the figure, reference numeral 1 denotes wave-shaped fins that are bent in a wave shape and arranged in parallel with a constant fin pitch Pf, with bent portions 2 at both ends.
A louver 3 is provided which is divided perpendicularly to 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 fin 1, and is composed of a long side 4a, a short side 4b, and a dividing plate 4C that divides the inside of the tube, and the long side 4a is parallel to the airflow direction A. A plurality of stages are provided in the horizontal direction with a stage pitch Pd. 5 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.

Regarding the finned heat exchanger configured as above,
The operation will be explained below using FIG. 12 and FIG. 13.

Heat exchange is performed between the airflow A flowing between the corrugated fins 1 and the refrigerant R flowing within the flat tube 4 via the corrugated fins 1 and the flat tube 4. At this time, since the louver 3 is divided and provided on the surface of the corrugated fin 1, the development of a temperature boundary layer of the air flow A generated on the surface of the corrugated fin 1 is suppressed, and the air pA
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 4C, 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, with the above configuration, when this finned heat exchanger is used as an evaporator and water droplets condense on the outer surface, as shown in FIG. Bent part 2
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 The air will accumulate on the upper surface of the pipe 4, and the airflow A
This causes an increase in ventilation resistance, and also impedes heat transfer between the corrugated fins 1 and the airflow A.

In view of the above problems, the present invention has been developed to improve the falling of water droplets even when water droplets condense on the outer surface by using this finned heat exchanger as an evaporator, thereby increasing the ventilation resistance of airflow and reducing the heat transfer coefficient. This is to suppress the decline.

Means for Solving the Problems In order to solve the above problems, the finned heat exchanger of the present invention includes a flat plate fin having a plurality of flat grooves formed by cutting out the front edge side in the airflow direction, and a flat plate fin. It consists of a flat pipe inserted into a flat groove from the side, and a drainage surface is provided on the surface downstream of the flat groove of the flat plate fin to communicate between the flat plate fins in the step direction, and the air flow is connected from the upstream side to the downstream side in the direction of gravity. It is equipped with a louver that is slanted.

Effect The present invention has the above-described configuration, so that even when this finned heat exchanger is used as an evaporator and water droplets condense on the outer surface, the airflow does not accumulate between the louvers that are inclined from the upstream side to the downstream side with respect to the direction of gravity. The accumulated water droplets move along the louver to the upper surface of the flat pipe on the downstream side under the influence of air current and gravity, and then fall to the lower stage through the drainage surface that communicates with the stage direction. This makes it possible to suppress increases in airflow resistance and decreases in 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 shape of the flat tube. In FIGS. 1 to 4, reference numeral 7 denotes a plurality of flat plate fins arranged in parallel at a constant fin pitch Pf, and flat grooves 8 formed by cutting out the leading edge side in the air inflow direction and forming at a constant pitch Pd in the stepped direction. and flat groove 8
A drainage surface 9 having a width W that communicates between the flat plate fins 7 in the step direction is provided on the more downstream surface. Further, on the surface of the flat plate fin 7, a louver 10 is also provided, which is formed by dividing the flat plate fin 7 and tilting it from the upstream side to the downstream side with respect to the direction of gravity. Reference numeral 11 denotes a flat tube that is inserted into the flat groove 8 of the flat plate fin from the front edge side and is tightly fitted, and is composed of a long side 11a, a short side 11b, and a dividing plate 11c that divides the inside of the tube.
A plurality of stages are provided with a stage pitch Pd. 12 is a header connected to both ends of the flat tube 11, and together with the flat tube 11 constitutes an internal flow path for the refrigerant R.

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

Heat exchange occurs between the airflow A flowing between the flat fins 7 and the refrigerant R flowing through the flat tube 11 via the ladder 12 via the flat fins 7 and the flat tube 11.

At this time, since the louver 10 is provided on the surface of the flat fin 7, the development of a temperature boundary layer of the airflow A generated on the surface of the flat fin 7 is suppressed, and the heat transfer coefficient between the airflow A and the flat fin 7 is reduced. Improvements are being made.

Moreover, the inside of the flat tube 11 is made into a microchannel by the dividing plate 11c, and the heat transfer coefficient between the flat tube 11 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 Figure 7,
Water droplets that accumulate between the louvers 10, which are inclined from the upstream side of the airflow to the downstream side with respect to the direction of gravity, move along the louvers 10 to the upper surface of the flat pipe 11 on the downstream side under the influence of the airflow A and gravity, and then become flattened. Since water can move downstream along the upper surface of the pipe 11 and fall to the lower stage along the drainage surface 9 that communicates with the subsequent stage, it improves the falling of water droplets and reduces the ventilation resistance of the airflow A. It is possible to suppress the increase in heat transfer coefficient and the decrease in heat transfer coefficient.

As described above, according to this embodiment, the flat fin 7 is provided with a plurality of flat grooves 8 formed by cutting out the front edge side in the airflow A direction, and the flat fin 7 is inserted into the flat groove 8 of the flat fin 7 from the side. A drainage surface 9 is provided on the surface of the flat plate fin 7 on the downstream side of the flat groove 8 to communicate the seven flat plate fins in the step direction. By providing the inclined louver 10, when this finned heat exchanger is used as an evaporator and water droplets condense on the outer surface, the louver is inclined from the upstream side to the downstream side with respect to the direction of gravity. The water droplets that accumulate between 10 and 10 move along the louver 10 to the upper surface of the flat pipe 11 on the downstream side under the influence of the airflow A and gravity, and then fall to the lower tier via the drainage surface 9 that communicates with the tier direction. As described above, the present invention has an advantage in that the leading edge side in the airflow direction is cut off. It consists of a flat plate fin with multiple stages of flat grooves, and a flat tube inserted into the flat groove of the flat plate fin from the side.
By providing a drainage surface that communicates between the flat plate fins in the step direction on the surface downstream of the flat groove of the flat plate fin, and providing a louver that is inclined from the upstream side of the airflow to the downstream side with respect to the direction of gravity, this fin-attached heat Even when the exchanger is used as an evaporator and water droplets condense on the outer surface, the water droplets that accumulate between the louvers, which are inclined from the upstream side of the airflow to the downstream side with respect to the direction of gravity, are affected by the airflow and gravity, and the water droplets condense on the outer surface. After moving along the upper surface of the flat tube on the downstream side, water droplets can fall to the lower tier along the drainage surface that communicates with the tiers. Decrease in transmissibility can be suppressed.

[Brief explanation of the drawing]

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. 7... Flat plate fin, 8... Flat groove, 9... Drainage surface, 10... Louver, 11... Flat tube. Name of agent Patent attorney Shigetaka Awano Haka 1 Rudder V-1 Glaze → Figure 3 IO-11 Louver 7- Kazuko Kei Finman 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure C 12 factors 3 Figure 13

Claims (1)

[Claims] Consisting of a flat fin having multiple stages of flat grooves formed by cutting out the front edge side in the airflow direction, and a flat tube inserted into the flat groove of the flat fin from the side, the flat fin is located downstream of the flat groove of the flat fin. A heat exchanger with fins, characterized in that a drainage surface is provided on the surface to communicate between the flat plate fins in the step direction, and a louver is provided that is inclined from one side upstream to the downstream side with respect to the direction of gravity.