JPS62284197A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent lowering of thermal conductivity between a fin and an air current even in a heat exchanger being long in an air current direction, by a method wherein, slit pieces, each having a front edge part positioned opposite to an air current, are formed in a parted state on a fin surface in two or more rows in a vertical direction to an air current, and the leg part of the slit piece is inclined based on an air current direction. CONSTITUTION:Fins 4 are positioned between straight tube parts 1', positioned facing each other, of a flat tube 1, and are secured in a wavefrom manner at intervals of a specified distance to the flat tube 1. Slit piece 5 are formed on the fin 4 surface so that a front edge part 5' extends vertically to an air flow B, and are parted in two or rows in a vertical direction to the air flow B. A leg part 5'', produced resulting from parting, is inclined based on the air flow B direction, and the leg parts 5'' are arranged in a mandering manner in the air current B direction. When heat exchange takes place between the air flow B and a heating medium flowing through the flat tube 1, the temperature boundary layer of the air current B, formed on the fin 4 surface, is parted by the slit pieces 5, the air flow B flows in a mandering manner on the fin 4 surface by means of the leg parts 5'', and a turbulence promoting effect is produced occasioned by production of an eddy current by virtue of the wake flow of the leg part 5''.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a heat exchanger used in air conditioning equipment, refrigeration equipment, etc.

Conventional technology In recent years, there has been a remarkable improvement in the performance of heat exchangers, and heat exchangers with corrugated fins, which feature a large air-side heat transfer area, have already been put into practical use mainly for automobiles. .

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

FIG. 4 shows a schematic shape of a conventional heat exchanger, and FIG. 6 shows its fin shape. In FIGS. 4 to 6, reference numeral 1 denotes a meanderingly bent flat tube having straight tube portions 1' substantially parallel to each other. 2 is a straight pipe part 1' facing the flat pipe 1;
The fins are provided between each other and are fixed to the flat tube 1 in a wave shape at regular intervals. Reference numeral 3 denotes a louver piece provided on the surface of the fin 2, with a front edge 3a facing the airflow A and a louver surface 3b inclined with respect to the airflow A.

The operation of the heat exchanger configured as above will be described below.

Heat exchange is performed between the airflow A flowing between the fins of the fins 2 and the heat medium flowing inside the flat tube 1 via the fins 2 and the flat tube 1. At this time, the louver piece 3 provided on the surface of the fin 2 interrupts the development of the temperature boundary layer of the airflow A generated on the surface of the fin 2, reducing the average thickness of the temperature boundary layer, and Due to the effect that the airflow A flowing on both sides is mixed and disturbed by the louver piece, the airflow A
A large heat transfer coefficient is obtained between the fins 20 and the fins 20.

Problems to be Solved by the Invention However, with the above configuration, the increase in ventilation resistance due to the louver pieces 3 is significantly large, and the temperature boundary layer of the airflow A generated on the surface of the fin 2 is not completely separated and flows downstream. The heat transfer coefficient between the air A and the fins 20 decreases as you go downstream, and especially in the case of a heat exchanger that is long in the air inflow direction, the heat exchange ability is extremely reduced. It had some problems.

In view of the above-mentioned problems, the present invention provides a heat exchanger that has a large heat exchange capacity without reducing the heat transfer coefficient between the fins and the airflow even in a heat exchanger that is long in the direction of the airflow.

Means for Solving the Problems In order to solve the above problems, the heat exchanger of the present invention has slit pieces on the fin surface whose front edges face the airflow and are divided into two or more rows in a direction perpendicular to the airflow. The leg portions of the slit pieces created by providing and dividing the airflow have an inclination with respect to the air flow direction.

Function: With the above-described configuration, the present invention divides the temperature boundary layer of the airflow generated on the fin surface by the slit piece to obtain a boundary layer leading edge effect, and also creates a vortex in the wake of the leg. A turbulent flow promotion effect is also obtained, and as a synergistic effect, the temperature boundary layer is further divided by the rear row slit pieces of the airflow that is turbulent due to the generation of vortices, so that the leading edge effect of the boundary layer is further increased. , the heat transfer coefficient between the airflow and the fins will be greatly improved.

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

FIG. 1 shows the fin shape of a heat exchanger according to an embodiment of the present invention. In FIGS. 1 and 2, reference numeral 1 denotes a flat tube, which has the same structure as the conventional one. 4 is flat tube 1
A fin provided between the opposite straight pipe portions 1',
They are fixed to the flat tube 1 in a wave shape at regular intervals. A slit piece 5 is provided on the surface of the fin 4 so that the front edge 6' is perpendicular to the direction of the airflow B, and is divided into two rows in the direction perpendicular to the airflow B, and a leg portion 6 formed by the separation. The legs 6'' are inclined in the direction of the airflow B, and the legs 6'' are arranged in a meandering manner in the direction of the airflow B.

The operation of the heat exchanger configured as described above will be explained below with reference to FIGS. 1 and 2.

Heat exchange is performed between the airflow B flowing between the fins of the fins 5 and the heat medium flowing inside the flat tube 4 via the fins 6 and the flat tube 4. At this time, the temperature boundary layer of the airflow B generated on the surface of the fin 6 is divided by the slit piece 6, so that a boundary layer leading edge effect is obtained that increases the leading edge where the local heat transfer coefficient is extremely high, and Airflow B by part 6
The turbulence promoting effect is obtained by flowing in a meandering manner on the surface of the fin 4 and generating vortices in the wake of the legs 6''.

In addition, as a synergistic effect, the temperature boundary layer of the airflow B disturbed by the legs 6' is further divided by the slit Katashima in the rear row, so that the leading edge effect of the boundary layer further increases, and the airflow and the fins are The heat transfer coefficient between the two is greatly improved.

As described above, according to this embodiment, the leading edge portion 6' is formed on the surface of the fin 4 by dividing the slit pieces 6 perpendicular to the airflow B direction into two rows in the direction perpendicular to the airflow B, and by dividing the slit pieces 6 into two rows perpendicular to the airflow B direction. The heat transfer coefficient between the fins 4 and the airflow B is greatly improved by making the leg portions 6'' inclined with respect to the direction of the airflow B and arranging the leg portions 6'' in a meandering manner in the direction of the airflow B. Even in a heat exchanger that is long in the direction of airflow B, the heat transfer coefficient does not decrease as it goes downstream, and a heat exchanger with a large heat exchange capacity can be obtained.

In this embodiment, the legs 6'' are arranged in a meandering manner in the airflow direction, but as shown in FIG. 3, the legs 5'' may be arranged in an intersecting shape in the airflow direction.

Effects of the Invention As described above, the present invention provides a fin surface with slit pieces whose front edges face the airflow divided into two or more rows in a direction perpendicular to the airflow, and legs of the slit pieces created by the separation. By making the fins slope with the airflow direction, the heat transfer coefficient between the fins and the airflow can be improved, and even in heat exchangers that are long in the airflow direction, the heat transfer coefficient can be maintained without decreasing the heat transfer coefficient toward the downstream side. A heat exchanger with excellent heat exchange ability can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a main part showing the fin shape of a heat exchanger in an embodiment of the present invention, Fig. 2 is a sectional view of the main part of Fig. 1, and Fig. 3 shows another embodiment of the invention. FIG. 4 is a perspective view of a conventional heat exchanger, and FIG. 6 is a perspective view of a main part showing the fin shape of FIG. 4. 1... Flat pipe, 1'... Straight pipe section, 4.
...Fin, 6...Slit piece, 6'.
...Front edge, S" ...leg. Name of agent: Patent attorney Toshio Nakao and 1 other person 4-
16n, 5°--Sussothi 6'--Ichigo-no-jyo-kor-Itsuyaku-no--No 1 Oh-h Kankan 7'--! Figure 1 4--1/=11F Figure 2 Figure 1' Figure 3 No' Figure 4

Claims (1)

[Claims] A flat tube bent in a serpentine shape and a fin stacked in a wave shape between the flat tubes, and slit pieces with front edges facing the airflow are arranged on the surface of the fin in two or more rows in a direction perpendicular to the airflow. A heat exchanger characterized in that the legs of the slit pieces formed by the separation are inclined with respect to the airflow direction.