JPS6233511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a finned tube heat exchanger used in air conditioners and the like.

2. Description of the Related Art Conventionally, a finned tube heat exchanger as shown in FIG. 1 has been used as a heat exchanger in an air conditioner or the like. That is, a large number of fins 1a are arranged in parallel at predetermined intervals to form a flat fin group 1, and the heat exchanger tubes 2 are passed through the flat fin group 1 at right angles in multiple stages. The air flows in the direction of the arrow between the flat fins 1a and exchanges heat with the refrigerant in the heat transfer tubes 2.

However, the thickness of the temperature boundary layer 3 on the heat transfer surface of the flat fin 1a of the heat exchanger having such a configuration is as follows.
As shown in Figure 2, the heat transfer coefficient increases in proportion to the square root of the distance from the air inlet, so as the distance from the air inlet increases, the air side heat transfer coefficient decreases significantly, and the heat transfer coefficient as a heat exchanger decreases. It had the disadvantage of low performance. Furthermore, as shown in FIG. 3, this structure also had the disadvantage of poor heat transfer performance due to the presence of a separation region 4 on the leeward side of the heat transfer tubes 2.

Furthermore, when this conventional heat exchanger is used as an evaporator, water droplets that condense near the heat transfer tubes 2 on the surface of the fins 1a do not fall immediately, but remain on the surface of the fins 1a and become air evaporators. This has the drawback of increasing ventilation resistance and further deteriorating heat transfer performance.

The present invention solves the above-mentioned conventional drawbacks,
The purpose is to significantly improve the heat transfer coefficient on the air side heat transfer surface, and also to improve the drainage of water droplets that condense on the fin surface near the heat transfer tubes when the heat exchanger is used as an evaporator. It is.

Hereinafter, the present invention will be explained with reference to FIGS. 4 and 5 of the accompanying drawings showing one embodiment thereof. here,
The heat exchanger of the present invention basically has the same structure as a conventional heat exchanger, but the structure of the fins is different from the conventional one.

In FIG. 4, the flat plate fin 1a has fin collar portions 1b which are barred at regular intervals,
A heat transfer tube 2 is inserted into this fin collar portion 1b. Reference numeral 5 denotes an uneven strip formed on the fin 1a by a press working means, etc., which is a groove between adjacent heat exchanger tubes 2 in a direction perpendicular to the flow of air flowing in the direction of the arrow, that is, in the step direction of the heat exchanger tubes 2. a straight line portion 5a along a straight line connecting in the step direction;
It is constituted by a detour portion 5b that detours the air to the lee side near the heat exchanger tube 2.

In the above configuration, the flow of air flowing between the respective fins 1a is disturbed by the straight portions 5a of the uneven strips 5, and the growth of the temperature boundary layer as it moves away from the air inflow portion is inhibited. Air flows along the detour portion 5b of the strip 5 to reduce the separation area present on the leeward side of the air flow of the heat exchanger tube 2. This greatly improves heat transfer performance.

Furthermore, when this heat exchanger is used as an evaporator, condensed water generated near the heat transfer tubes 2 on the surface of the flat plate fin 1a is guided to the detour portion 5b of the uneven strip 5 by the air flow in the direction of the arrow. After that, the concavo-convex strips 5 fall rapidly and continuously due to capillary action, which improves water drainage, prevents increase in ventilation resistance, and maintains stable heat transfer performance over a long period of time. can.

In this embodiment, the cross section of the uneven strip 5 is made into an acute angle shape as shown in FIG. 5, but the same effect can be obtained even if the uneven shape is formed so that the cross section becomes a sinusoidal wave shape or a square wave shape. .

Further, the effect that can only be obtained on one side when a concave or convex shape is formed on one side of the fin 1a can be obtained over both the front and back sides of the fin 1a by forming continuous uneven strips 5 as in this embodiment. It will be done.

As is clear from the above embodiments, the finned tube heat exchanger of the present invention includes a fin group consisting of a large number of fins that are arranged in parallel at predetermined intervals and through which air flows, and a multistage fin group. A finch-tube heat exchanger is constituted by a group of heat transfer tubes that are perpendicular to each other and through which a refrigerant passes, and a step of the heat transfer tube group is formed in a mutual gap in the step direction of the heat transfer tube group in each fin of the fin group. It is provided with uneven stripes extending in the direction and detouring to the leeward side near the heat transfer tube group, which promotes turbulence in the air circulation and reduces the separation area, so the air side heat transfer coefficient is significantly improved. Even when this heat exchanger is used as an evaporator, since the uneven stripes have a narrow width, ventilation is required for a long time to improve the drainage of condensed water generated near the heat transfer tubes on the surface of the fins. It has various effects such as improved heat transfer performance and stable and good heat transfer performance.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional finned tube heat exchanger, Figure 2 is a diagram of thermal fluid characteristics on the surface of the heat exchanger's fins, and Figure 3 is a diagram of the heat exchanger near the heat exchanger tubes. FIG. 4 is a plan view of a main part of a finned tube heat exchanger according to an embodiment of the present invention, and FIG. 5 is a sectional view taken along line A-A in FIG. 4. 1...Heat exchanger, 1a...Flat fin, 1b...
... Fin collar part, 2 ... Heat exchanger tube, 5 ... Uneven strip, 5a ... Straight line part, 5b ... Detour part.

Claims (1)

[Claims] 1. A fin group consisting of a large number of fins arranged in parallel at predetermined intervals and through which air flows;
A finned tube heat exchanger is constituted by a heat exchanger tube group in which the fins are orthogonal to each other in multiple stages and through which a refrigerant passes, and a mutual gap in the stage direction of the heat exchanger tube group in each fin of the fin group is formed. A finned tube heat exchanger having a narrow uneven strip extending in the step direction of the heat exchanger tube group and detouring to the leeward side in the vicinity of the heat exchanger tube group.