JPH02197796A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To permit the falling of water drips from gaps between flat tubes to a lower stage along the draining surface of a flat plate fin even when a heat exchanger is used as an evaporator and the water drips are produced by condensation and are adhered to the outer surface of the heat exchanger by a method wherein draining surfaces, pinched by flat groove provided at the side of a fore rim and the same provided at the side of an aft rim, are provided on the surface of the flat plate fin while the flat tubes are divided by the draining surface utilizing it as a boundary. CONSTITUTION:A heat exchanger is constituted of flat plate fins 7, provided with a plurality of stages of flat grooves 8 constituted by notching both ends of fore and aft rims, and flat tubes 1, inserted from side surfaces into the flat grooves 8 of the flat plate fins 7 arranged in parallel to each other with a given fin pitch Pf, and is provided with draining surfaces 9, pinched by a fore rim side flat groove 8f and aft rim side flat grooves 8r, on the flat plate fins 7 while the flat tubes 11 are divided by the draining surface 9 utilizing it as a boundary. When the finned heat exchanger is used as an evaporator and water drips L adhered to the outer surface of the heat exchanger by condensation, the water drips L may be dropped to a lower stage through the gaps (w) between the divided flat tubes 11 along the draining surface 9 of the flat fins 7. Accordingly, the increase of the ventilating resistance of air stream A as well as the deterioration of heat transfer rate 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 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.

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 8 divided in the direction of the airflow A is provided.

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.

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 via the corrugated fins 1 and the flat tube 4. At this time, since the louver 3 is provided in sections on the surface of the corrugated fin 1, the development of a temperature boundary layer of the airflow A generated on the surface of the corrugated fin 1 is suppressed, and the airflow A
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 plates 4 and C, 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 This accumulates on the upper surface of the tube 4, causing an increase in ventilation resistance to the airflow, and also impeding heat transfer between the corrugated fins 1 and the airflow.

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 both ends of the front and rear edges, and It consists of a flat tube inserted from the side into a flat groove, and a drainage surface is provided on the surface of the flat plate fin sandwiched between the flat groove on the front edge side and the flat groove on the rear edge side, and the flat tube is inserted with this drainage surface as a boundary. This is a modification of the structure of dividing.

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 water droplets are transmitted through the drainage surface of the flat fin from the gap between the divided flat tubes. Since the water droplets can fall to the lower level, 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.

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. 3 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, which are formed by cutting out both ends of the front and rear edges in six directions of airflow, and are arranged at a constant pitch Pd in the step direction. A drainage surface 9 having a width W is provided between the flat grooves 8 on the leading edge side and the flat grooves 8f on the leading edge side and the flat grooves 8r on the rear edge side. Further, on the surface of the flat fin 7, louvers 10 are also provided, which are obtained by dividing the flat fin 7 into six directions of air flow. Reference numeral 11 denotes a flat tube inserted into the flat groove 8 of the flat plate fin from both ends of the front and rear edges, and the long side 11
a, a short side 11b, and a dividing plate 11c that divides the inside of the tube, and the flat tube 1 on the leading edge side is formed with a gap of width W in the direction of the step pitch Pd so that the long side 11a is parallel to the direction of the airflow A.
1. f and a flat tube 11r having a trailing edge 1Itq. Headers 12 are connected to both ends of the flat tube 11, and together with the flat tube 11 constitute 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.

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 microchannels by the dividing plate 10c, 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 can flow down the drain surface 9 of the flat plate fin 7 from the gap of the width W of the divided flat tube 11 to the lower stage, making it easier for the water droplets I- to fall and providing ventilation to the airflow. It is possible to suppress an increase in resistance and a decrease in heat transfer coefficient.

As described above, according to this embodiment, the flat plate fins 7 are provided with a plurality of flat grooves 8 formed by cutting out both ends of the front and rear edges, and the flat plate fins 7 are arranged in parallel at a constant fin pitch Pf. A flat tube 11 is inserted into the flat groove 8 from the side, and a flat groove 8 on the front edge side is formed on the surface of the flat plate fin 7.
By providing a drainage surface 9 sandwiched between f and the flat groove 8r on the trailing edge side, and dividing the flat tube 11 along this drainage surface 9, this finned heat exchanger can be used as an evaporator, and the outer surface When the water droplets condense in the flat pipe 11, the water droplets I pass through the drainage surface 9 of the flat plate fin 7 from the gap of the width W of the divided flat tube 11.
- can fall to the lower stage, so water droplets can fall smoothly, and an increase in ventilation resistance of the airflow A and a decrease in heat transfer coefficient can be suppressed.

Effects of the Invention As described in 2., the present invention provides a flat plate fin having a plurality of flat grooves formed by cutting out both ends of the front and rear edges, and a flat tube inserted from the side into the flat groove of the flat plate fin. This finned heat exchanger is made of Even when used as an evaporator and water droplets condense on the outer surface, the water droplets can fall to the lower stage through the gap between the divided flat tubes and the drainage surface of the flat fin, making it easier for water droplets to fall. This makes it possible to suppress increases in airflow resistance and decreases in heat transfer coefficient.

[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, 11... Flat pipe. Name of agent: Patent attorney Shigetaka Awano and 1 other person No. 3 Fig. Wako board fin rO-1-12-B Fig. 4 7 Noor Peng back 4' Office Fig. Fig. 1 O-Rouba Jl-Flat pipe Kasumi° Gusushi No. 10 Fig. 11 C

Claims (1)

[Claims] It consists of a flat plate fin with a plurality of flat grooves formed by cutting out both ends of the front and rear edges, and a flat tube inserted into the flat groove of the flat plate fin from the side. A finned heat exchanger characterized in that a drainage surface is provided between the groove and the flat groove on the trailing edge side, and the flat tube is divided along the drainage surface.