JPH04136692A - Fin for heat exchanger - Google Patents

Abstract

PURPOSE:To improve leading edge effect effectively and increase an efficiency upon heat exchanging by a method wherein a long hole is formed along the lengthwise direction of a slit type cut-and-raised part between the slit type cut-and-raised part and neighboring fins at the downstream side or the upstream side of the flow direction of air. CONSTITUTION:A long hole 5 is formed along the lengthwise direction of a slit type cut-and-raised part 3 between one part of the slit type cut-and-raised part 3 and a fin neighbored to the downstream side of the flow direction of air. The long hole 5 is formed actually so that the length of the flow direction of two pieces of downstream side slit type cut-and-raised parts 3 among four pieces of slit type cut-and-raised parts 3 formed between heat transfer tubes 2 neighboring in an intersecting direction becomes shorter compared with a case wherein the long hole 5 is not formed so as to reduce an ineffective area with respect to the slit type cut-and-raised part 3. According to this method, the efficiency of heat exchange can be increased based on the leading edge effect in a boundary layer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fin for a heat exchanger, and more specifically, the present invention relates to a fin for a heat exchanger. The present invention relates to a heat exchanger fin in which a plurality of raised fins are arranged in a row at intervals along the gas flow direction.

[Conventional technology]

A plurality of such heat exchanger fins are arranged in parallel, and a heat exchanger tube is attached to the heat exchanger fins so as to pass through them, thereby assembling a heat exchanger. More specifically, the plurality of heat exchanger fins are arranged in parallel in a spaced apart manner so that gas (for example, air) can flow through the gaps between them, and furthermore, the heat exchanger fins are arranged in a spaced apart manner so that a heat medium fluid can flow therethrough. The resulting heat exchanger tubes are attached in a penetrating state, thereby assembling a heat exchanger that is widely used as an evaporator, condenser, etc. in air conditioning equipment.

In such a heat exchanger, gas is allowed to flow through the gaps between the fins, while heat medium fluid is allowed to flow inside the heat transfer tubes, and heat exchange is performed between the two. In order to increase efficiency during heat exchange, the fins are designed in various shapes.

For example, a plurality of slit-shaped cut-and-raised parts, which are formed by cutting and raising a part of a fin into a band shape along the direction intersecting the gas flow direction, are arranged in parallel at intervals along the gas flow direction. There is something that has been formed. In a heat exchanger equipped with such fins, due to the presence of the slit-shaped cut and raised portions, a boundary layer is generated in the gas flow (hereinafter simply referred to as air flow) starting from the leading edge of the slit-type cut-and-raised portions. Based on this effect, the efficiency during heat exchange increases.

[Invention or problem to be solved]

By the way, it seems that the more slit-shaped cut-and-raised parts are formed in the flow direction, the better the effect is, or even if an attempt is made to improve the effect by increasing the number of slit-shaped cut-and-raised parts formed, there is a limit.

That is, if the length of the slit-type cut-and-raised piece in the flow direction is L, then the other slit-type cut-and-raised piece is connected over a length of 3L in the downstream region of the boundary layer that starts from the leading edge of one slit-type cut-and-raised piece. It is known that there exists a region (hereinafter referred to as an ineffective region) in which the above-mentioned effect does not occur even if it is provided. In this way, the number of slit-shaped cut-and-raised formations can be increased (
Even if we try to improve the leading edge effect, there are limits.
Even if more than a certain number of slit-shaped cut-and-raised portions are formed on a fin having a certain effective planar area, there is a problem in that the pressure loss increases, which is rather disadvantageous. In addition,
The problem of the existence of the invalid area also occurs in the fin portion remaining after the slit-type cut-and-raise is cut and raised.

The present invention has been made in view of the above circumstances, and it is possible to form a large number of effective slit-type cut-and-raised or effective fin portions in the flow direction while avoiding a situation where the pressure loss increases only. It is an object of the present invention to provide a fin for a heat exchanger that can effectively improve the leading edge effect and thereby improve the efficiency during heat exchange.

[Means to solve the problem]

A characteristic configuration of the fin for a heat exchanger of the present invention is such that a length along the longitudinal direction of the slit-shaped cut-and-raised portion is provided between the slit-shaped cut-and-raised portion and the fin portion adjacent to the downstream or upstream side of the flow direction. The reason is that holes are formed, and the effects are as follows.

[For production]

In the finned heat exchanger of the present invention, the elongated hole is formed between the slit-shaped cut and raised portion and the fin portion adjacent to the downstream side or upstream side of the elongated hole in the flow direction, or the form of the elongated hole is Specifically, there are cases as described below.

In the case where the elongated hole or the slit-shaped cut-and-raised length in the flow direction is formed to be smaller than that in the case where no elongated hole is formed, the invalid area with respect to the slit-shaped cut-and-raised length. becomes smaller. Further, when the elongated hole is formed so that the length of the fin portion in the flow direction is smaller than that in the case where the elongated hole is not formed, the above-mentioned Invalid area becomes smaller. Further, when the elongated hole is formed so as to shorten the length of both the slit-shaped cut-and-raised portion and the fin portion in the flow direction, the ineffective area becomes smaller with respect to the image portion.

〔Effect of the invention〕

Thus, in any of the above cases, since the ineffective area in the slit-shaped cut-and-raised or fin portion can be made small, the density of the slit-shaped cut-and-raised or fin portion in the flow direction can be reduced by reducing the pressure loss. You will be able to increase the size while avoiding the situation of increasing it too much. Therefore, it is possible to form a large number of effective slit-type cut-and-raised portions or effective fin portions in the flow direction while avoiding a situation where the pressure loss increases, thereby effectively improving the leading edge effect. It becomes possible to improve the efficiency during the heat exchange.

〔Example〕 Embodiments of the present invention will be described below with reference to the drawings.

As shown in Fig. 3, a plurality of fins (1) are arranged in parallel at a certain distance apart, and a gas (
For example, gaps are formed to allow air (for example, air) to flow in the direction shown by the white arrow in the figure. Further, a heat transfer tube (2) is inserted into the fin (1), and a heat medium fluid is passed through the fin (1). The structure is such that heat exchange is performed between the gas flowing through the gap between the fins (1) and the heat medium fluid flowing through the inside of the heat transfer tube (2).

As shown in FIGS. 1 and 2, the fin (1) is partially cut and raised in a direction that intersects with the flow direction (see the white arrow mark) (hereinafter referred to as the "crossing direction"). A large number of band-like slit-shaped cut-and-raised tubes 3) are formed (in this embodiment, one is formed between the heat exchanger tubes (2) that are adjacent to each other in the flow direction, and one is formed between the heat exchanger tubes (2) that are adjacent to each other in the cross direction. (2) four of them are formed between each other), and the heat exchange efficiency is increased based on the leading edge effect of the boundary layer caused by their presence. Note that the leading edge effect also occurs in the fin portion remaining after the slit-shaped cut-and-raise 3) is cut and raised, thereby increasing the efficiency of heat exchange.

Now, between a part of the slit-shaped cut and raised part 3) and the fin part adjacent to it on the downstream side in the flow direction,
A long hole (5) along the longitudinal direction of slit-shaped cut and raised 3)
) is formed. Specifically, among the four slit-shaped cut-and-raised parts 3) formed between the heat exchanger tubes (2) adjacent to each other in the cross direction, the two slit-shaped cut-and-raised parts 3) on the downstream side are The elongated hole (5) is formed so that the length in the flow direction is smaller than that in the case where the elongated hole (5) is not formed, and the ineffective area is made smaller with respect to 3) where the slit shape is cut and raised. It is.

[Another example]

As shown in FIG. 4, the heat exchanger tubes (2
) 4 slit-shaped cutouts formed between each other 3
), an embodiment is also conceivable in which the elongated holes (5) are formed so that the length along the flow direction of the two upstream side slit-shaped cut-and-raised holes (3) is shortened. Note that the elongated hole (5) is provided on the upstream side of the slit-shaped cut and raised part 3).
An embodiment in which a is formed is also possible.

Further, as shown in FIG. 5, the fin portion (1a
) may be an embodiment in which the elongated hole (5) is formed so as to shorten the length along the flow direction.

Further, as shown in FIG. 6, the fin portion (la
) may be an embodiment in which the elongated hole (5) is formed so as to shorten the length along the flow direction.

Furthermore, the manner of formation of the slit-shaped cut-and-raised part 3) may be different from that of the above-mentioned embodiment, for example, as shown in FIGS. two heat exchanger tubes (2) between each other, two adjacent heat exchanger tubes (2) in the cross direction;
) Of course, the present invention can also be applied to a case where three pieces are formed between each other. In this embodiment, the most downstream slit-shaped cut-and-raised part 3) of the three slit-shaped cut-and-raised parts 3) formed between the heat exchanger tubes (2) adjacent to each other in the cross direction is connected. The elongated hole (5) is formed so that the length in the flow direction is short.

Further, the length of the slit-shaped cut and raised portion 3) formed on the fin (1) in all flow directions is shortened.
It is also conceivable to form the elongated hole (5). However, in this case, by providing the elongated hole (5), the heat transfer area of the slit-shaped cut-and-raised part 3) will be reduced, but the final heat exchange efficiency will be lowered due to this reduction. Of course, this should not happen.

Furthermore, even if part or all of the slit-shaped cut-and-raised part 3) is cut-and-raised in the opposite direction to the above-described embodiment, the present invention can be applied.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

FIG. 1 is a plan view showing essential parts of an embodiment of the finned heat exchanger of the present invention, FIG. 2 is a sectional view taken along the line IF-I in FIG. 1, and FIG. A perspective view showing the exchanger, FIGS. 4 to 7 are plan views showing main parts of another embodiment of the finned heat exchanger of the present invention, and FIG. 8 is a cross section taken along the line ■-■ in FIG. 7. It is a diagram. (3)...Slit-shaped cut and raise, (5)...
...Long hole.

Claims (1)

[Claims] A plurality of slit-shaped cut-and-raised parts (3), each of which is partially cut and raised in a band shape along a direction intersecting the gas flow direction, are arranged at intervals along the gas flow direction. The fins for a heat exchanger are formed in a lined state, and the slit-shaped cut-and-raised part (3) is provided between the slit-shaped cut-and-raised part (3) and the fin portion adjacent to the downstream or upstream side of the flow direction. A long hole (5) along the longitudinal direction of the raised (3)
) or formed heat exchanger fins.