JPS61272593A - Heat exchanger - Google Patents

Abstract

PURPOSE:To obtain a large amount of heat transfer, by providing many divided bent pieces at air-stream inlet ends of fins, and providing slits on the surface of the fins. CONSTITUTION:Heat exchange is carried out between air stream flowing between fins 4 and a heat medium flowing in heat medium pipes 2. At this time, since the fin unit 4 is divided into many columns in the direction of the air stream B, development of boundary layers yielded on the surfaces of the fins is divided. The air stream B is largely disturbed by the heat medium pipes 2, which are arranged in a zig-zag shape, and bent pieces, which are provided at the air-stream inlet ends of the fins 4. Thus heat transfer is accelerated. Furthermore, since slits 6 are positioned on the downstream side of the air stream B immediately after the bent pieces 5, the boundary layers yielded in the vicinities of the slits 6 becomes very thin even if a fin pitch (d) is large. Even if the height (e) of the slit 6 is relatively low with respect to the fin pitch (d), the slits 6 are not included in the boundary layers but divides the boundary layers. Therefore, the thickness of the boundary layer is kept very thin and the very large heat transfer can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fin-tube heat exchanger used in air conditioners, freezers, refrigerators, and the like.

2. Description of the Related Art In recent years, the performance of heat exchangers has improved dramatically, and staggered pipe heat exchangers and completely independent fin heat exchangers have already been put into practical use.

The conventional heat exchanger mentioned above will be explained below with reference to FIGS. 3 and 4.

In the figure, reference numeral 1 denotes a large number of small fins arranged in parallel, which are divided into rows in the air inflow direction.

Reference numeral 2 denotes heat medium pipes that pass through the fins 1 and are arranged in a staggered manner.

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

Heat exchange occurs between the airflow A flowing between the fins of the fins 1 and the heat medium flowing inside the heat medium pipe 2. At this time, since the fins 1 are divided into each row in the direction of the airflow A, the development of the boundary layer generated on the fin surface is divided, and due to the leading edge effect of the boundary layer, a large amount of heat is generated between the airflow A and the fins 1. Getting the transmission. Furthermore, since the heat medium pipes 2 are arranged in a staggered manner, the turbulence of the airflow A is increased, and the airflow A and the fins 1 are
A large heat transfer is obtained between the heat medium pipe 2 and the heat medium pipe 2.

Problems to be Solved by the Invention However, with the above configuration, the boundary layer formed on the surface of the fins 1 does not become extremely thin, and the airflow disturbed by the heat medium pipes 2 arranged in a staggered manner There was a problem in that A was reversely rectified by the fins 1, making it impossible to obtain sufficiently large heat transfer.

Generally, heat transfer can be improved by providing the slits 3 on the surface of the fins 10, but in those with a relatively large fin pitch a, the height b of the slits 3 also increases as the fin pitch a increases. On the other hand, the fin plate thickness C is around 0,15-15mm compared to the conventional one due to cost considerations, so the height b of the slit 3 is smaller than the fin pitch a from the viewpoint of fin processing. It was not possible to make the height sufficiently high, and there was also the problem that the improvement in heat transfer by the slits 3 was small.

In view of the above-mentioned problems, the present invention provides a heat exchanger that can obtain extremely large heat transfer.

Means for Solving the Problems In order to solve the above-mentioned problems, the heat exchanger of the present invention has a plurality of divided twisted pieces at the air inlet end, and a large number of twisted pieces on the surface of the air flow downstream part of the twisted pieces. A fin with a slit,
and a heat medium pipe passing through the fins.

Operation According to the above-described configuration of the present invention, the airflow flowing between the fins is greatly disturbed by the twist piece, and the boundary layer formed on the fin surface is divided by the slit, so that the thickness of the boundary layer is maintained thin.

Moreover, since the airflow that forms the boundary layer is disturbed by the twisted piece at the inlet end, the boundary layer formed on the fin surface is thin even if the fin pitch is large, and the height of the slit is relatively low compared to the fin pitch. The boundary layer can be sufficiently divided even when the boundary layer is thinned, and the thickness of the boundary layer can be maintained thin.

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

FIG. 1 shows a heat exchanger in one embodiment of the present invention. In FIG. 1, numeral 4 denotes a large number of fins arranged in parallel, which are divided into rows in the direction of airflow B. Reference numeral 6 denotes a twist piece provided at the air inlet end of the fin 4, which is divided into many pieces. Numeral 6 denotes slits provided on the surface of the fin 4, which are provided in large numbers. Reference numeral 2 denotes a heat medium tube, which has the same structure as the conventional one.

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

Heat exchange occurs between the airflow B flowing between the fins of the fins 4 and the heat medium flowing inside the heat medium tube 2. At this time, since the fins 4 are divided into rows in the direction of the airflow B, the development of a boundary layer that occurs on the fin surface is divided, and the heat transfer pipes 2 and the air inlet of the fins 4, which are arranged in a staggered manner, are separated. Heat transfer is also promoted by the airflow B being disturbed by the twist piece 6 provided at the end. Furthermore, since the slit 6 is located immediately downstream of the twist piece 6 with respect to the airflow B, even if the fin pitch d is large, the boundary layer generated near the slit θ is extremely thin, and the slit 6
Even if the height e is relatively low with respect to the fin pitch d, the slit 6 is not included in the boundary layer and can divide the boundary layer to maintain a thin boundary layer thickness.

As described above, according to this embodiment, the twist piece 5 is connected to the fin 4.
By providing a large number of slits 6 at the air inlet end of the fin 4 and providing the slits 6 on the surface of the fin 4, the airflow B forming a boundary layer is disturbed by the twisted piece 6 at the inlet end, and even if the fin pitch d is large, the fin 4 The boundary layer formed on the surface becomes thin, and even if the height e of the slit 6 is relatively low with respect to the fin pitch d, the slit 6 is not included in the boundary layer but divides the boundary layer, and the boundary layer thickness can be kept thin for extremely high heat transfer.

Effects of the Invention As described above, the present invention further increases the effect of the slits by providing a large number of twisted pieces at the air inlet end of the fin and providing a large number of slits on the fin surface. The boundary layer can be kept thin to obtain extremely high heat transfer.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a heat exchanger in an embodiment of the present invention;
2 is a perspective view of a main part showing the fin of FIG. 1, FIG. 3 is a perspective view of a conventional heat exchanger, and FIG. 4 is a perspective view of a main part showing the slit shape of a conventional heat exchanger. 2... heat medium pipe, 4... fin, 5...
...Twist piece, 6...Slit. Name of agent: Patent attorney Toshio Nakao and 1 other person2.
...Netsu-sama + t-threat 4...Finn

Claims (1)

[Claims] It consists of a large number of fins arranged in parallel and a heat medium pipe passing through the fins, and a plurality of twisted pieces are divided and provided at the air inlet end of the fins, and on the fin surface of the airflow trailing part of the twisted pieces. A heat exchanger with many slits.