JPS60194293A - Heat exchanger equipped with fin - Google Patents

Abstract

PURPOSE:To increase heat transfer performance, miniaturize the heat exchanger with fins and provide the same with a high performance by a method wherein slit type rise- up cuts having legs with curvatures are provided so as to oppose to the flow line of air stream in order to reduce dead water area generated in the wake flow of heat transfer tube. CONSTITUTION:A flat plate fin 7 is provided with slit type rise-up cuts 11, 12, having legs with curvatures concentrical to the center of the heat transfer tube 9. The flat plate fin 7 is provided with the slit type rise-up cuts 11, 12 previously, therefore, a condition that short fins are arranged in the direction of the air stream is realized and thin temperature boundary layers are formed around the short fins respectively, consequently, the heat transfer efficiency of air side is improved remarkably. On the other hand, the legs 13 of the slit type rise-up cuts are provided with proper angles and curvatures with respect to the flow line of the air stream, therefore, the flow line of the air stream is changed smoothly and the pressure loss of the stream is also reduced remarkably. Further, the slit type rise-up cuts 12, arranged between the heat transfer tubes in first and second rows, are provided radially with respect to the heat transfer tube 9, therefore, the dead water area, generated around the heat transfer tube 9, may be reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a finned heat exchanger for gas-gas-liquid two-phase flow (or liquid), which is widely used in evaporators, condensers, etc. in the field of air conditioning equipment. It is something.

Structure of the conventional example and its problems As shown in the perspective view of Fig. 1, the conventional heat exchanger consists of a flat plate fin group 1 arranged in parallel at regular intervals,
It consists of a group of heat transfer tubes 2 inserted at right angles to the fins, and air flows between the fins in the direction of the arrow 3 to exchange heat with the fluid inside the tubes. As shown in the plan view of FIG. 2 and the A-A cross-sectional view of FIG. 4.
There are 6.

With this kind of fin shape, slit type cutting and raising 4
, 6 are each formed with a thin temperature boundary layer, and it is thought that the heat transfer performance is improved by the so-called boundary layer leading edge effect. However, with this structure, it cannot be expected to reduce the dead water holes 6 on the upstream side of the airflow, that is, at the rear of the front row of heat transfer tubes, and the promotion of heat transfer performance is limited.

In addition, as shown in the plan view of Figure 4, when the slit-type cut-and-raised parts are provided radially, the cut-and-raised legs do not follow the streamlines when the airflow is guided to the dead area. In some cases, the heat transfer performance will be improved only slightly if the airflow is not allowed to flow into the dead zone 6 due to resistance and a large pressure loss occurs.

OBJECT OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the conventional technology.In particular, it improves heat transfer performance by reducing the dead zone that occurs at the trailing end of heat exchanger tubes, and improves the heat exchanger with fins. The aim is to make the system more compact and high-performance.

Structure of the Invention The finned heat exchanger of the present invention is composed of flat plate fins arranged in parallel at regular intervals, through which air flows, and heat transfer tubes inserted at right angles to the flat plate fins, through which fluid flows. , a flat plate fin is provided with a slit-shaped cut and raised leg having a concentric curvature from the center of the heat exchanger tube. However, the height of the slit-type cut-and-raise mentioned above is maintained for heat transfer. Furthermore, when this heat exchanger with fins is used as an evaporator, the flat plate fins and the slit-shaped cut-and-raised parts are subjected to hydrophilic treatment.

DESCRIPTION OF EMBODIMENTS A finned heat exchanger according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is a plan view of the fins in the heat exchanger, and FIG. 6 is a sectional view taken along the line BB' in FIG.

Fin collar portions 8 provided at regular intervals on the flat fin 7
A heat exchanger tube 9 is inserted into the flat fin, and a slit-type cut 9 is provided between the heat exchanger tubes of the flat plate fin. The arrangement of the slit-type cut and raise will be explained below.

Between the upstream side of the airflow flowing in the direction of arrow 1o, that is, the line connecting the centers of the first row of heat transfer tubes, and the fin front edge, there are two side parts parallel to the fin front edge (upstream end with respect to the airflow). A plurality of slit-type cut and raised legs 11 are arranged which are open and have leg portions 13 having a clear curvature relative to the streamline of the airflow.

Further, a similar slit-type cut-and-raise 11 is provided between the line connecting the centers of the second row heat exchanger tubes and the trailing edge of the fin (the downstream end with respect to the airflow). Next, between the first row heat exchanger tube and the second row heat exchanger tube, there are openings on two sides in a direction perpendicular to the streamline of the airflow, and the leg portion 13 in the streamline direction is formed in a concentric circle with the center of the heat exchanger tube. Alternatively, a slit-shaped cut-and-raised portion 12 having an appropriate curvature may be provided. Note that FIG. 9 is a side view seen from the airflow inflow direction in FIG. 6, and FIG. 10 is a side view seen from the airflow inflow direction in FIG.

Next, the action and effects will be explained. First, since the flat plate fin 7 is provided with slit-type cut-and-raised parts 11 and 12,
The flat plate fins 7 have short fins lined up in the airflow direction 9, and since a thin temperature boundary layer is formed on each of these short fins, the air side heat transfer coefficient is significantly improved. Further, since the slit-shaped cut and raised leg portions 13 have an appropriate angle and curvature with respect to the streamlines of the airflow, the streamlines of the airflow are changed clearly and the pressure loss is significantly reduced. And 1
Since the slit-shaped cut-and-raised portions 12 arranged between the heat exchanger tubes in the first and second rows are provided radially on the heat exchanger tubes 9, the dead area generated around the heat exchanger tubes 9 is significantly reduced. Furthermore, as shown in Figures 7, 8, and 10, if only the height of the leg closer to the heat transfer tube is reduced and the slit type cut-and-raise is tilted, the airflow will be reduced. This promotes the introduction of heat into the heat exchanger tubes, which is effective in reducing dead areas. As a result, the air-side heat transfer coefficient is significantly improved, and the heat exchanger can be made smaller and more efficient.

Next, when this heat exchanger is used as an evaporator, hydrophilic treatment is applied to the flat plate fins and slit-shaped cut-outs to prevent deterioration of heat transfer performance due to condensation and maintain the above heat transfer performance. let

Effects of the Invention As described above, the present invention reduces the dead area, improves heat transfer performance, and allows a finned heat exchanger to be made smaller and more efficient.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional heat exchanger, Fig. 2 is a plan view of the fins in Fig. 1, Fig. 3 is a sectional view taken along line AA' in Fig. 2, and Fig. 4 is FIG. 5 is a plan view of a fin in a heat exchanger according to an embodiment of the present invention; FIG. 6 is a sectional view taken along line B-B' in FIG. 5; FIG. 8 is a plan view of a fin in a heat exchanger according to a different embodiment of the present invention, FIG. 8 is a sectional view taken along the line C-C' in FIG. 7, and FIGS. It is a side view seen from the airflow inflow direction. 7... Flat plate fin, 8... Fin collar, 9... Heat exchanger tube, 10... Air flow direction arrow, 1.1.12... ...Slit type cut and raised, 13...Cut and 9 raised legs, 14...
Cut-up wing section. Name of agent: Patent Attorney Toshio Tsuchinakao and 1 other person Figure 1 Figure 3 Figure 4i! 1 Figure 5

Claims (2)

[Claims] (1) Consists of flat plate fins that are arranged in parallel at regular intervals, through which air flows, and heat transfer tubes that are inserted at right angles to the flat fins and through which fluid flows; A heat exchanger with fins in which a slit-type cut-and-raised leg having a curvature that allows for clear deflection is provided so as to face the streamline of the airflow. (2) The heat exchanger with fins according to claim 1, wherein the height of the slit-shaped cut and raised portions arranged on the flat plate fins around the heat transfer tubes is made smaller on the side closer to the heat transfer tubes, and the slits are inclined. vessel. G3) The heat exchanger with fins according to claim 1 or 2, wherein the flat plate fins and the slit-type cut and raised portions arranged on the flat plate fins are subjected to hydrophilic treatment.