JPH0313794A - Heat exchanger with fin - Google Patents

Abstract

PURPOSE:To improve the falling of water droplets, and to inhibit the increase of the draft resistance of an air current and the lowering of a heat transfer rate by forming flat grooves at plural stages and composing reference cores of plate fins, on downstream-side surfaces of which drainage surfaces communicating in the stepped direction are shaped, and flat pipes inserted into the flat grooves from side faces. CONSTITUTION:Flat grooves 6 constituted by notching front edge sides in the direction of an air current are shaped at plural stages, reference cores 10 are composed of plate fins 5, on stream-side surfaces of which lower than the flat grooves 6 drainage surfaces 7 communicating in the stepped direction are formed, and flat pipes 8 inserted into the flat grooves 6 of the plate fins 5 from side faces, and a plurality of the reference cores 10 are arranged in the direction of the air current. Consequently, even when the heat exchanger with the fins is used as an evaporator and water droplets L condense on outside surfaces, water droplets L staying on the top faces of the flat pipes 8 are pushed by the air current A, moved to the downstream side, transmitted on the drainage surfaces 7 communicating in the stepped direction and can be dropped to lower steps. Accordingly, falling in the direction of gravity (g) of the water droplets L is improved, and the increase of the draft resistance of the air current A and the lowering of a heat transfer rate can be inhibited.

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

Figs. 5 and 6 show the shapes of conventional finned heat exchangers. In Figs. 2 is a flat tube that is closely attached to the bent portions 1a at both the upper and lower ends of the corrugated fin 1, and a plurality of rectangular channels 3 are formed in the tube, and the cross section is A plurality of steps are formed in a meandering manner in the horizontal direction with a step pitch Pd so that the longitudinal direction is parallel to the air direction. 4 is a flat tube 2.
The headers connected to both ends of the flat tube 2 form a flow path for the refrigerant R together with the flat tube 2.

The heat exchanger with fins configured as described above has airflow A flowing between the parallel portions 1b of the corrugated fins 1 and refrigerant R flowing through the rectangular flow path 3 in the flat tubes 2.
Normally, the heat exchange ability is improved by reducing the fin pitch Pf of the corrugated fins 1 to improve the heat transfer coefficient with the airflow A and increase the heat transfer area with the airflow A. ing. The heat exchange capacity can also be improved by reducing the equivalent diameter of the rectangular flow path 3 in the flat tube 2, increasing the number of rectangular flows u3, improving the heat transfer coefficient with the refrigerant R, and increasing the heat transfer area of the refrigerant R. It's improving.

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 1a
Not only do water droplets accumulate inside the fins, but since the corrugated fins 1 of each stage are separated by flat tubes 2, the water droplets that travel along the surface of the corrugated fins 1 and fall in the direction of gravity g do not reach the lower stage. It is difficult to fall and accumulates on the upper surface of the flat tube 2, causing an increase in the ventilation resistance of the airflow A, causing water droplets to fly to the back surface, and furthermore impeding heat transfer between the corrugated fins 1 and the airflow A. Moreover, the greater the depth dimension in the air inflow direction, the more this phenomenon occurs.

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 8 Problems In order to solve the above problems, the finned heat exchanger of the present invention has a plurality of flat grooves formed by cutting out the leading edge side in the air flow direction, and a flat groove on the downstream side of the flat groove. A reference core is constituted by a flat plate fin having a drainage surface communicating in the step direction on its surface and a flat tube inserted from the side into the flat groove of the flat plate fin, and the reference cores are arranged in multiple rows in the airflow direction. It is equipped with the following.

Effect of the present invention With the above-described configuration, even 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 are pushed by the airflow and move downstream. After that, water drops can fall to the lower tier via the drainage surface that communicates with the tiers, making it easier for water droplets to fall.
It is possible to suppress an increase in airflow resistance and a decrease in heat transfer coefficient.

Furthermore, even if the depth dimension in the airflow direction increases, this can be handled by increasing the number of rows of reference cores, and the falling of water droplets will not be hindered.

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 finned heat exchanger according to an embodiment of the present invention, and Figure 3 shows the shape of a flat plate fin. A plurality of flat plate fins arranged in parallel with a fin pitch Pf are formed by cutting out the front edge side in the air inflow direction, and have flat grooves 6 arranged at a constant step direction pitch Pd, and a surface downstream from the flat grooves 6. A drainage surface 7 with a width W that communicates between the flat plate fins 5 in the step direction.
is provided. Reference numeral 8 denotes a flat tube that is inserted into the flat groove 6 of the flat plate fin 5 from the leading edge side, and a plurality of rectangular channels 9 are formed in the tube, and the tube is oriented horizontally so that the longitudinal direction of the cross section is parallel to the air inflow direction. A plurality of stages are provided at a stage pitch Pd. Reference numeral 10 denotes a reference core consisting of the flat fins 5 and a plurality of stages of flat tubes 8, which are arranged in four rows in the air inflow direction. 11 is a header connected to both ends of the flat tube 8;
Together, they form a flow path for the refrigerant R.

The heat exchanger with fins configured as described above has a structure in which the air flow A flowing between the flat plate fins 5 and the refrigerant R flowing in the rectangular flow path 9 in the flat tubes 8 are connected via the flat plate fins 5 and the flat tubes 8. Heat exchange takes place. Usually, the heat exchange ability is improved by reducing the fin pitch Pf of the flat fins 5 to improve the heat transfer coefficient with the air flow A and increase the heat transfer area with the air mA. The heat exchange capacity can also be improved by reducing the equivalent diameter of the rectangular flow path 9 in the flat tube 8, increasing the number of rectangular flows wr9, improving the heat transfer coefficient with the refrigerant R, and increasing the heat transfer area of the refrigerant R. It's improving.

Also, when this finned heat exchanger is used as an evaporator and water droplets Lf condense on the outer surface, as shown in Fig. 4,
The water droplets that accumulate on the upper surface of the flat tube 8 are pushed by the airflow and move downstream, and then fall to the lower stage through the drainage surface 7 that communicates with the stage direction. It is possible to suppress an increase in the ventilation resistance of the airflow A and a decrease in the heat transfer coefficient. Further, even if the depth dimension in the direction of the airflow A increases, this can be handled by increasing the number of rows of the reference cores 10, and the falling of water droplets will not be hindered.

As described above, according to this embodiment, a plurality of flat grooves 6 formed by cutting out the front edge side in the airflow A direction are provided, and a drainage surface 7 communicating in the step direction is provided on the surface downstream of the flat grooves 6. A reference core 10 is constituted by the provided flat plate fin 5 and a flat tube 8 inserted from the side into the flat groove 6 of the flat plate fin 5, and by arranging a plurality of the reference cores 10 in a plurality of rows in the airflow direction, this fin When the heat exchanger is used as an evaporator and water droplets L2y are condensed on the outer surface, the water droplets that accumulate on the upper surface of the flat tube 8 are pushed by the airflow A and move downstream, and are then drained to the stage direction. Since the water droplets can fall to the lower stage along the surface 7, 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.

Furthermore, even if the depth dimension in the air inflow direction increases, this can be handled by increasing the rows and number of reference cores 10, and water droplets will not be obstructed from falling.

Effects of the Invention As described above, the present invention provides a flat plate fin having a plurality of stages of flat grooves formed by cutting out the front edge side in the airflow direction, and a drainage surface communicating in the step direction on the surface downstream of the flat grooves. and a flat tube inserted into the flat groove of the flat plate fin from the side. By arranging multiple rows of the standard cores in the airflow direction, this finned heat exchanger can be used as an evaporator. Even when water droplets condense on the surface, the water droplets that accumulate on the upper surface of the flat tube can be pushed by the airflow and move downstream, and then travel along 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. Furthermore, even if the depth dimension in the airflow direction increases, this can be handled by increasing the number of rows of reference cores, and the falling of water droplets will not be inhibited.

[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, Figure 4, Figure 1
Figure 5 is a perspective view showing the shape of a conventional finned heat exchanger, Figure 6 is a perspective view of the main part of Figure 5, and Figure 7 is the water droplet in Figure 5. FIG. 3 is a cross-sectional view showing the state of adhesion. 5... Flat plate fin, 6... Flat groove, 7... Drainage surface, 8... Flat tube, 10... Reference core.

Claims (1)

[Claims] A flat plate fin having a plurality of stages of flat grooves formed by cutting out the front edge side in the airflow direction and a drainage surface communicating in the step direction on the surface downstream of the flat grooves, A finned heat exchanger characterized in that a reference core is constituted by the inserted flat tube, and the reference cores are arranged in a plurality of rows in the airflow direction.