JPS58158497A - Finned-tube type heat exchanger - Google Patents

Abstract

PURPOSE:To reduce water cutoff regions at parts on the downstream of heat- transmitting pipes and contrive to enhance heat-transmitting efficiency at heat- transmitting surfaces on the air side, by a method wherein projections faced orthogonally to an airflow are provided on the surfaces of fins at positions in proximity to and on the downstream side (with respect to the airflow) of each row of heat-transmitting pipes. CONSTITUTION:The fins 1 are provided with fin collar parts 4 formed by burring at regular intervals, and the heat-transmitting pipes 2 are passed through the fin collar parts 4. The projections 5 faced orthogonally to the airflow are provided on the surfaces of the fins 1 at the positions in proximity to and on the downstream side (with respect to the airflow passed in the direction of arrows) of each row of the pipes 2. Accordingly, the airflow passing in the direction of the arrows is shut off by the projections 5 provided at the parts on the downstream of the pipes 2, and enters into the parts, thereby reducing the water cutoff regions. Accordingly, since heat is sufficiently exchanged between the fins 1 of the pipes 2 and the airflow even in the regions on the downstream of the pipes 2, the heat-transmitting performance of the heat exchanger can be enhanced.

Description

[Detailed Description of the Invention] In recent years, with the reduction in noise from air conditioning equipment, there has been a growing tendency to design heat exchangers with front wind speeds of 1 meter per second or less. Improving performance is an issue.

The present invention proposes a structure of a heat exchanger that satisfies the above-mentioned demands, and in particular reduces the stop area downstream of the heat transfer tubes by using the fin shape, and significantly improves the heat transfer coefficient on the air side heat transfer surface. This is what we aim to do.

Conventionally, this type of heat exchanger is composed of a large number of flat plate fins 1 arranged in parallel at regular intervals and a large number of heat transfer tubes 2 inserted at right angles to the flat plate fins 1, as shown in FIG. 2a. The airflow flows between the flat plate fins 1 in the direction of the white arrow to exchange heat with the fluid inside the pipe. As shown in Figure 2, the thermal fluid characteristics of the heat exchanger tubes 2 between the flat fins 1 are as follows: When a low wind speed airflow flows through the heat exchanger tubes 2 in the direction of the white arrow, from the stagnation point on the surface of the heat exchanger tubes 2 The angle e is ±
At 7oo-+8oO, the flow separates, and a cut-off area 3 is generated downstream of the heat exchanger tube 2, as shown by the diagonal line in the center of FIG.

As a result, the air-side heat transfer coefficient in this water stop area 3 is significantly reduced, resulting in a drawback that the heat transfer performance as a heat exchanger is low.

The present invention considers the above-mentioned problems and solves them.

An embodiment of the present invention shown in FIG. 1 will be described below.

FIG. 1a is a front view of a fin 1 in a finned heat exchanger showing an embodiment of the present invention, in which heat transfer tubes 2 are attached to fin collar portions 4 formed by burring at regular intervals on the fin 1.
is inserted, and the airflow is perpendicular to the airflow direction, that is, on the surface of the fin 1 between the front and rear heat transfer tubes 20 in the row direction located at the downstream part near the heat transfer tubes 2, flowing in the direction of the white arrow. Protrusions 6 facing each other are provided. FIG. 1 is a cross-sectional view taken along line A ++ A' in FIG. 1a, showing the cross-sectional shape of the protrusion 6.

Next, the operation will be explained.

When airflow flows in the direction of the white arrow in the finned heat exchanger composed of fins 1 and heat exchanger tubes 2, the thermal fluid characteristics of the heat exchanger tubes 2 are as follows.

In other words, the angle θ from the stagnation point on the surface of the heat transfer tube 2 is ±7
The airflow separated at 00 to 80° is blocked by the protrusion 5 provided at the closest part of the downstream part of the heat exchanger tube 2, and enters the downstream part of the heat exchanger tube 2, significantly reducing the stop area 3. do.

Therefore, heat exchange between the heat exchanger tubes 2 and the fins 1 and the airflow can be performed sufficiently even in the downstream region of the heat exchanger tubes 2, so that the heat transfer performance of the heat exchanger is significantly improved.

Furthermore, as shown in FIG.
On the other hand, it acts as a bead, increases the strength of the fin 10, and also strengthens the stiffness of the fin 1, thereby improving the productivity of the fin 1.

Furthermore, since the protrusions 6 are formed at the closest portion of the heat exchanger tubes 2, when the heat exchanger is used as a cooler, condensed water generated near the heat exchanger tubes 2 on the surface of the fins is removed from the protrusions. 5
It travels along the surface and falls quickly. Therefore, it has various effects such as being able to reduce the ventilation resistance of the heat exchanger during cooling operation.

In this embodiment, the cross-sectional shape of the protrusion 6 is a sawtooth shape, but it is clear that other shapes, such as a groove shape, or even if the fin 1 is cut and raised, will have the same effect. It is.

As described above, the present invention is composed of a group of fins arranged in parallel at regular intervals and a group of heat exchanger tubes inserted at right angles to the group of fins. Since this is a finned heat exchanger with protrusions facing perpendicularly to the fins on the fin surface in the gap, the stop area after the heat transfer tubes is significantly reduced, which impairs the heat transfer performance of the heat exchanger. In addition, when used as a cooler, the protrusions allow condensed water to flow out quickly and reduce ventilation resistance.Furthermore, the protrusions are arranged perpendicular to the inflow direction of airflow. Since it is formed continuously, it acts as a bead for the fin, increasing the strength of the fin, improving the manufacturability of the fin, and having many effects.

[Brief explanation of drawings]

Fig. 1a is a front view of a finned heat exchanger according to an embodiment of the present invention, Fig. 1 is a sectional view taken along line A-A7 of Fig. 1a, and Fig. 2a is a conventional finned heat exchanger. Perspective view of the vessel,
Figure 2 is a diagram of thermal fluid characteristics in the same heat exchanger. 1... Fin, 2... Heat exchanger tube, 3...
・・Water stop, 4・・・Part of fin collar, 5・・・・
・Protrusion. Name of agent: Patent attorney Toshio Nakao and one other person II
Figure/R) lb)

Claims (1)

[Claims] It is composed of a group of fins arranged in parallel at regular intervals and a group of heat exchanger tubes inserted at right angles to the group of fins, and on the fin surface of the gap in the row direction located in the downstream area near the heat exchanger tubes. A finned heat exchanger with protrusions facing perpendicular to the airflow.