JPH0610592B2 - Heat exchanger with fins - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a finned heat exchanger for gas-to-liquid two-phase fluid (or liquid) which is widely used in evaporators, condensers and the like in the field of air conditioning equipment. It is a thing.

Configuration of conventional example and its problems In recent years, with the noise reduction of air conditioners, there is an increasing tendency to design the front wind speed of the heat exchanger to be 1 m / sec or less, and the heat exchanger in such a low wind speed region. Improving the performance of is an issue.

Conventionally, as shown in FIG. 1, this type of heat exchanger has a group of flat plate fins 1 arranged in parallel at regular intervals and a group of fins 1 thereof.
The heat transfer tube group 2 is inserted at a right angle to the air, and air flows between the fins in the direction of arrow 3 to exchange heat with the fluid in the tube. 2 and 3 are cross-sectional views of the flat plate fin 1 taken along the line A-A 'in FIG. 2, and as shown in FIG. Slit-shaped raised portions 4 and 5 are provided.

With such a fin shape, a thin temperature boundary layer is formed in each of the slit-shaped cut-and-raised parts 4 and 5, so-called
It was said that the heat transfer performance was improved by the boundary layer leading edge effect. However, this structure has a drawback that the air flow is stagnated at the rear part of the heat transfer tube 2 and the thermal resistance between the fins and the air is significantly increased, that is, the so-called dead water area cannot be reduced. Furthermore, when examining the local heat transfer performance, the upstream side of the air flow, that is, in the previous example, the boundary layer leading edge effect of the slit-shaped cut-and-raised portion 4 is large and the heat transfer performance is high, but the air flow downstream side, that is, the rear row Since the air heat-exchanged in the slit-shaped cut-and-raised parts 4 in the front row passes through the cut-and-raised parts 5 without mixing with the air having a large temperature difference with the wall in the central part of the fin, it has a drawback of low heat transfer performance. There is.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, in particular to promote the boundary layer leading edge effect by increasing the fin leading edge portion length and reduce the dead water area in the wake of the heat transfer tube. The purpose of the present invention is to improve the heat transfer coefficient on the air side by accelerating the mixing of the flows, and to improve the size and performance of the finned heat exchanger.

The heat exchanger with fins of the present invention is composed of flat plate fins that are arranged in parallel at regular intervals and through which an air flow flows, and heat transfer tubes that are inserted at right angles into the flat plate fins and through which the fluid flows. In the portion of the flat plate fin located between the heat transfer tubes, a plurality of cut-and-raised parts are provided so that two side portions facing the air flow are opened so as to intersect with the flat plate fin.

Description of Embodiments A heat exchanger with fins according to one embodiment of the present invention will be described below with reference to the drawings. 4 is a plan view and FIG. 5 is A- in FIG.
It is an A'plane sectional view. A heat transfer tube 8 is inserted in a fin collar portion 7 burred on the flat plate fin 6 at regular intervals. In the portion of the flat plate fin 6 located between the heat transfer tubes 8,
A plurality of cut-and-raised parts 11 each having a curved surface portion 9 and a leg portion 10 are provided so that two side portions facing the air flow are opened so as to intersect with the flat plate fins 6.

The cut-and-raised part 11 is a fin collar 7 into which the heat transfer tube 8 is inserted.
It is arranged around and opposite to the streamline of the air flow. Further, the leg portion 10 has an attack angle and a curvature that smoothly turn the streamline with respect to the streamline of the airflow. Further, the cut-and-raised parts 11 and 1 whose crossing directions with the two side portions and the flat plate fin 6 are mutually opposite
2 are alternately arranged from the upstream side of the air flow.

Next, the operation and effect will be described. First, by opening the two side portions of the flat plate fin 6 facing the airflow so as to intersect with the flat plate fin 6, the heat transfer area can be increased by increasing the length of the cut and raised front edge portion, and the boundary layer leading edge effect can be achieved. Can be effectively utilized. Further, the cut-and-raised parts 11 and 12 are arranged so as to face the streamline of the airflow, and the leg portion 10 has an attack angle and a curvature that smoothly turn the streamline with respect to the streamline of the airflow. As a result, the air flow cuts and rises around the heat transfer tube 8 and flows along the arrows 11 and 12 as indicated by an arrow 13, thereby preventing the air flow from being separated from the heat transfer tube 8. Therefore, the air flow is
It also enters the wake area and reduces the dead water area. Further, as shown in FIG. 6, since the cut-and-raised parts 11 and 12 in which the crossing directions of the two side portions and the flat plate fin 6 are opposite to each other are arranged alternately from the upstream side of the air flow, part of the air flow is Flow as indicated by arrow 14 and flow mixing is promoted.

The leg portion 10 and the curved portion 9 need not be clearly distinguishable as in the embodiment, but may be formed by a continuous curved surface portion.

As described above, by opening the two side portions facing the air flow on the flat plate fin so as to intersect with the flat plate fin, it is possible to increase the heat transfer area by increasing the length of the cut and raised front edge. The edge effect can be used effectively, and the cut and raised legs have an angle of attack and curvature, and the cut and raised portions are arranged opposite to the streamline of the airflow, so that the airflow around the heat transfer tube separates from the heat transfer tube. To prevent this, the dead water area can be significantly reduced. Further, since the two side portions and the flat plate fin are alternately arranged so that the crossing directions are opposite to each other from the upstream side of the air flow, the flow mixing is promoted.

EFFECTS OF THE INVENTION From the above, the present invention can realize a fin heat exchanger in which the heat transfer coefficient on the air side is remarkably improved and the size and performance can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a conventional heat exchanger, FIG. 2 is a plan view of the flat plate fin in FIG. 1, FIG. 3 is a sectional view taken along the line AA ′ of FIG. 2, and FIG. Is a plan view of a flat plate fin in a heat exchanger according to an embodiment of the present invention, and FIG. 5 is B- in FIG.
FIG. 6 is a cross-sectional view of the B'plane, and FIG. 6 is a perspective view of the essential parts of FIG. 6 ... Flat plate, 7 ... Fin collar, 8 ... Heat transfer tube, 9 ... Curved section, 11,12 ... Cut and raise.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiyuki Tsuda 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. 56) References Japanese Unexamined Patent Publication No. 58-69396 (JP, A) Actual No. 57-139086 (JP, U)

Claims (2)

[Claims] 1. A flat plate fin which is arranged in parallel at a constant interval and through which an air flow flows, and a heat transfer tube which is inserted at a right angle to the flat plate fin and through which a fluid flows inside. Is provided with a plurality of cut-and-raised parts each having a leg portion provided on the front and back of the flat plate fin and two side portions facing the air flow, and an intersection angle θ between the two side portions and the flat plate fin.
A heat exchanger with fins in which the cut-and-raise of a degree and the cut-and-raised of a crossing angle (180-θ) are arranged alternately in the air flow direction. 2. The heat exchanger with fins according to claim 1, wherein the surface having the two side portions is a flat surface or a curved surface.