JPS62178888A - Heat exchanger - Google Patents

Abstract

PURPOSE:To provide a heat exchanger in which the heat transfer coefficient thereof between fins and an air stream is not lowered even in a heat exchanger long in the air stream direction and the heat exchange ability is large, by forming slitted and raised portions in parallel to the air stream direction into fin surfaces by bending a part of fins. CONSTITUTION:Heat exchange is carried out between an air stream B flowing through fins 5 and a heat medium flowing inside a flat pipe 1 via the fins 4 and the flat pipe 1. Upon this occasion, since the development of a temperature interface layer of the air stream B generated on the surface of fins 4 is interrupted by slitted and raised surfaces 5 and a long hole 6, and the slitted and raised surfaces 5 are formed vertically with the fins 4, the direction of development of the temperature interface layer generated on the slitted and raised surfaces becomes vertical with that of the temperature interface layer generated on the surface of fins 4. Therefore, the temperature interface layer is completely divided, and the temperature interface layer front edge effect of a maximum limit can be obtained. Further, since the slitted and raised surface 5 is formed in parallel to the direction of the air stream B, the reduction in the ventilation resistance can be realized.

Description

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.

Figure 3 shows the schematic shape of a conventional heat exchanger, and shows the second half-
/ Figures 3 and 4 show the shape of the fins.

In FIG. 4, reference numeral 1 denotes a flat tube bent in a meandering manner, and is provided with straight tube portions 1' substantially parallel to each other. Fins 2 are provided between the opposing straight pipe portions 1' of the flat tube 1, and are fixed to the flat tube 1 at regular intervals in a wave shape. 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 in the airflow generated on the surface of the fin 2, reducing the average thickness of the temperature boundary layer. Due to the effect that the airflow A flowing on both sides is mixed and disturbed by the root sepals, a large heat transfer coefficient is obtained between the airflow A and the fins 20.

Problem 3 to be Solved by the Invention: However, in the above configuration, the increase in ventilation resistance due to the louver pieces 3 is extremely large, and the temperature boundary layer of the airflow A generated on the surface of the fin 2 is completely separated. The heat transfer coefficient between the airflow A and the fins 2 decreases as you go downstream, especially in the case of a heat exchanger that is long in the air inflow direction. There was a problem in that the value decreased.

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 a configuration in which a cut and raised surface parallel to the air flow direction is formed on the fin surface by bending a part of the fin. It is something that

Effects The present invention has the above-mentioned configuration, unlike the conventional louver piece, which does not change the flow direction of airflow and therefore does not increase ventilation resistance, and by bending the cut and raised surfaces. Due to the elongated holes in the fins, the temperature boundary layer of the airflow generated on the fin surface is completely separated, and the leading edge effect of the boundary layer can be maximized.

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 in a first embodiment of the present invention. In Figures 1 to 2, 1
is a flat tube with 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. Reference numeral 6 denotes a cut-and-raised surface formed on the surface of the fin 4 by vertically bending a part of the fin 4, and is provided parallel to the air flow B direction, and a plurality of cut and raised surfaces are provided in a staggered arrangement in the air flow B direction.

A long hole 6 is formed on the surface of the fin 4 by bending the cut and raised surface 6. Further, the fins 4 are in contact with the raised surface 5 through the cut and raised surfaces 5 formed from adjacent fins, and the fin pitch of the fins 4 is determined by the cut and raised height h of the cut and raised surface 6.

The operation of the heat exchanger configured as described above will be explained below using 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 1 via the fins 4 and the flat tube 1. At that time, the development of the temperature boundary layer of the airflow B generated on the surface of the fin 4 is divided by the cut and raised surface 5 and the elongated hole 6, and since the cut and strained surface 6 is formed perpendicular to the fin 4, The direction of development of the temperature boundary layer formed on the surface of the surface 6 is perpendicular to the direction of development of the temperature boundary layer formed on the surface of the fin 4, and the temperature boundary layer is completely separated to maximize the leading edge effect of the boundary layer. Become.

Further, since the cut and raised surface 6 is formed parallel to the direction of the airflow B, ventilation resistance can be reduced.

As described above, according to this embodiment, by bending a part of the fin 4 to form the cut and raised surface 5 and the elongated hole 6,
By reducing ventilation resistance and maximizing the edge effect in front of the boundary layer, the heat transfer coefficient between the fins 4 and the airflow B is increased, and even in a heat exchanger that is long in the direction of the airflow B, the heat transfer rate increases as it goes downstream. Heat exchange ability can be improved without reducing transfer coefficient.

Furthermore, since the fin pitch of the fins 4 is determined by the cut-and-raise height h of the cut-and-raise surface 6, the fin pitch of the fins 4 is maintained appropriately, and the strength is also increased.

Effects of the Invention As described above, the present invention reduces ventilation resistance and maximizes the leading edge effect of the boundary layer by bending a part of the fin to form a cut and raised surface on the surface of the fin. To obtain a heat exchanger with excellent heat exchange ability, which maintains a high heat transfer coefficient between the air flow and the air flow, and does not reduce the heat transfer coefficient toward the downstream side, especially in a heat exchanger that is long in the air flow direction. be able to.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a main part showing the fin shape of a heat exchanger according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line 7/C-C of Fig. 1, and Fig. 3 is a sectional view of a conventional heat exchanger. A perspective view of a heat exchanger,
4 is a perspective view of a main part showing the fin shape of FIG. 3. FIG. 4...Fin, 6...Cut and raised surface, 6.
...Long hole.

Claims (1)

[Claims] It is characterized by comprising a flat tube bent in a meandering manner and fins stacked in a wave shape between the flat tubes, and a cut and raised surface parallel to the air flow direction is formed by bending a part of the fin. Heat exchanger.