JPH02251093A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To improve the dropping of water drips condensed on the outer surface of flat tubes and prevent the increase of the ventilating resistance of airflow as well as the deterioration of heat transfer rate by a method wherein a draining surface, communicating between flat fins in the direction of stages, is provided at the downstream side of flat grooves of the flat fin while the inserting direction of flat tubes into the flat grooves is slanted into the direction of gravity. CONSTITUTION:A finned heat exchanger is constituted of flat fins 7, provided with a plurality of stages of flat grooves 8 constituted by notching the leading edge of the fin in the direction of airflow A, and flat tubes 11, inserted into the flat grooves 8 of the flat fin 7 from the side thereof, while a draining surface 9, communicating between the flat fins in the direction of the stages, is provided at the downstream side of the flat grooves 8 of the flat plate fin 7 and the inserting direction of flat tubes 11 into the flat grooves 8 is slanted into the direction of gravity (g). When water drips L are condensed on the outer surface of the fin 7, the water drips L, stagnating on the upper surfaces of the flat tubes 11, move toward downstream side along the upper surfaces of the slanted flat tubes 11 and, thereafter, drop to a lower stage along the draining surface 9 communicated in the direction of the stages whereby the dropping of the water drips L may be improved and the increase of the ventilating resistance of the airflow A as well as the deterioration of the heat transfer rate of the title heat exchamber 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 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 device design, and efforts have been made to improve efficiency by improving the fin shape and the inner surface shape of the tubes.

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

8 to 14 show the shape of a conventional finned heat exchanger. In the figure, 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 a looper 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 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 direction of airflow 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. Then, 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 into three pages on the surface of the corrugated fin 1, the airflow A generated on the surface of the corrugated fin 1 is
The development of the temperature boundary layer is suppressed, and airflow A and corrugated fin 1
The aim is to improve the heat transfer coefficient between the In addition, the inside of the flat tube 4 is made into a microchannel by the dividing plate 4°C, and the flat tube 4
The heat transfer coefficient between the refrigerant R 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. Not only will water droplets accumulate inside the bent portion 2 of the fins, but also because the corrugated fins 1 of each stage are separated by the flat tubes 4,
Water droplets that travel down the surface of the corrugated fins 1 are difficult to fall to the lower stage and accumulate on the upper surface of the flat tube 4, causing an increase in the ventilation resistance of the airflow A, and the heat generated between the corrugated fins 1 and the airflow A. It also inhibits transmission.

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 the flat plate fin. and a flat tube inserted from the side into the flat groove of the flat plate fin, and a drainage surface that communicates between the flat plate fins in the step direction is provided on the surface downstream of the flat groove of the flat plate fin, and the flat tube is inserted into the flat groove. It has a configuration in which the direction is tilted in the direction of gravity.

Effect of the present invention With the above-described configuration, even when this finned heat exchanger is used as an evaporator and water droplets are condensed on the outer surface, the water droplets that accumulate on the upper surface of the flat tube are caused to flow along the slanted upper surface of the flat tube. After moving to the downstream side, water can fall to the lower tier via the drainage surface that communicates with the tiers, so water droplets can fall well and suppress the increase in airflow resistance and the decrease in heat transfer rate. I can do it.

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

Figures 1 and 2 show the shape of a heat exchanger with fins in an uninvented embodiment, and Figure 3 shows the shape of a flat fin,
FIG. 41 shows the shape of the flat tube.

In Figures 1 to 4, 7 is a constant fin pitch P
A plurality of flat plate fins arranged in parallel at f are cut out on the front edge side in the air inflow direction, and a flat groove 8 is formed at a constant pitch Pd in the stepped direction, diagonally from the front edge side in the direction of gravity g at about j, and a 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 surface downstream of the fins 8 . Further, on the surface of the flat fin 7, a louver 10, which is obtained by dividing the flat fin 7 in the air inflow direction, is also provided. Reference numeral 11 denotes a flat tube which is inserted and tightly fitted into the flat groove 8 of the flat plate fin from the front edge side with an inclination in the direction of gravity g, and is composed of a long side 11a, a short side 11b, and a dividing plate 11c that divides the inside of the tube. 11a is on the downstream side class 6
The pages are arranged in a plurality of slanted rows with a row pitch of Pd. 12
are headers connected to both ends of the flat tube 11, and together with the flat tube 11 constitute 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 on page 7, the water droplets accumulated on the upper surface of the flat tube 11 are A drainage surface 9 that moves downstream along the upper surface of the flat pipe 11 that is inclined in the direction and communicates with the downstream direction.
Since the water droplets can fall to the lower stage through the water, 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.

As described above, according to this embodiment, the flat fin 7 has a plurality of flat grooves 8 formed by cutting out the front edge side in six airflow directions, 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 downstream surface of the flat plate fins 7 from the flat grooves 8 to communicate between the flat plate fins 7 in the step direction, and a drain surface 9 is provided on the surface of the flat plate fins 7 on the downstream side from the flat grooves 8. By tilting the finned heat exchanger in the direction of gravity g, when this finned 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 11 are removed from the flat tube 11. After moving downstream along the sloping upper surface of the water droplet, the water can fall to the lower tier via the drainage surface 9 that communicates with the tiers, which improves the falling of water droplets and increases the ventilation resistance of the airflow A. Decrease in heat transfer coefficient can be suppressed.

Effects of the Invention As described above, the present invention comprises a flat fin having a plurality 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. 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 fin, and by slanting the insertion direction of the flat tube into the flat groove in the direction of gravity, this fin attachment 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 top surface of the flat tubes move downstream along the slanted top surface of the flat tubes and then communicate in the direction of the stages. Since the water droplets can fall to the lower level along the drainage surface, it is possible to improve the falling of water droplets and suppress an increase in the ventilation resistance of the airflow and a decrease in the heat transfer coefficient.

[Brief explanation of drawings]

Figure 1 on page 9 is a perspective view showing the shape of a finned heat exchanger in an embodiment of the present invention, Figure 2 is a perspective view of the main part of Figure 1, and Figure 3 shows the shape of the flat fin in Figure 1. FIG. 4 is a sectional view showing the shape of the flat tube shown in FIG. 1, FIG. 5 is a sectional view showing the flow state of airflow in the usage state of FIG. Figure 7 is a cross-sectional view showing the state of water droplet adhesion in Figure 1, Figure 8 is a perspective view showing the shape of a conventional finned heat exchanger, and Figure 9 is a cross-sectional view of the circuit shown in Figure 8. Perspective view of main parts,
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. 18 is a perspective view showing the refrigerant circuit in 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, 11... Flat pipe. Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 1O Figure 1C Figure 12 Figure 14

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 the insertion direction of the flat tubes into the flat grooves is inclined in the direction of gravity.