JPS60216188A - Fin of heat exchanger - Google Patents

Abstract

PURPOSE:To increase the heat transfer area per unit volume of a heat exchanger and consequently promote the heat transfer by a structure wherein wavy projections continuous in the direction of stage are formed on fins at the clearance part in the direction of the stage of heat transfer pipes. CONSTITUTION:The bondaries 8a in the direction of the stage between the planes 6 and 7 of a fin 1 and projections 4 are continuous to the planes 6 and 7 of the fin 1, while the boundaries 8b in the direction of the row are discontinuous to the planes 6 and 7 of the fin 1. When the vertical angle theta2 of the apex 5 of the projection 4 takes 90 deg. and the angle of intersection theta3 of the center line (l) of the plate thickness of the fin 1 and the projection 4 takes 45 deg., the heat transfer area of the fin with the projections 4 is about 1.41 times larger than the heat transfer area of a flat plate fin without the projections 4. In addition, the heat flow from heat transfer pipes flows nearly as indicated with the arrows I and the heat flow toward the projections 4 is scarcely hindered because the boundaries 8a are continuous to the planes 6 and 7 of the fin 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in cross-fin tube heat exchangers that are often used in air conditioners and the like.

Conventional configuration and its problems In general, in order to promote heat transfer between the fins of a heat exchanger and the airflow flowing between them, it is considered to increase the heat transfer area per unit volume.

Figure 1 shows a conventional cross-fin tube heat exchanger that uses the above concept to promote heat transfer.
There is a heat exchanger using corrugated fins, as shown in FIG. 2, in which the fins 1 are continuously bent in a waveform in the row direction to increase the fin area. However, corrugated fins mainly have a turbulent flow promotion effect that promotes heat transfer by turbulating the airflow with the corrugated fins 1, and because the apex angle θ1 of the corrugated peaks of the fins 1 is large, compared to flat fins. In this case, the expansion rate of the fin area is small, and the promotion of heat transfer by increasing the heat transfer area is supplementary. 1a
is the heat exchanger tube insertion hole.

As described above, it can be said that there have been practically no heat exchangers that have promoted heat transfer mainly by increasing the heat transfer area of the heat exchanger per unit volume.

OBJECTS OF THE INVENTION The present invention obviates these conventional drawbacks.
Increase heat transfer area per unit volume to promote heat transfer,
At the same time, the objective is to obtain heat exchanger fins that can promote heat transfer due to the foreground effect and whose fin material costs are the same as those of conventional heat exchangers using flat fins.

Structure of the Invention The heat exchanger of the present invention is a cross-fin tube type heat exchanger in which a heat transfer tube has 11 fins, and the fins in the gaps in the step direction of the heat transfer tubes are continuous in the step direction. By forming wave-shaped protrusions, the heat transfer area per unit volume is increased to promote heat transfer, and the front image effect also promotes heat transfer, and the fin material cost is reduced compared to conventional flat fins. It is no different from the heat exchanger that was used.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 6.

In FIGS. 3 to 6, 1 is a fin, 2 is a through hole of a heat exchanger tube (not shown), and a collar 3 is provided to regulate the distance between the fins 1. Reference numeral 4 denotes a wave-shaped protrusion continuous in the direction of one step formed on the fin 1 in the gap in the step direction of the through hole 2, and the top 6 of the protrusion 4 is a plane on the X side and Y side of the fin 1, respectively. , 7 are evenly protruded. In addition, the protrusion 4 is made of the material forming the fin 1 (general □
By taking advantage of the malleability of aluminum (usually aluminum) and applying pressure from the outside with a press or the like, it is formed into continuous protrusions ranging from flat to wavy. Planes 6, 7 of fin 1
The boundary 8a in the column direction of the protrusion 4 is continuous with the planes 6 and 7 of the fin 1, but the boundary 8b in the column direction is continuous with the plane 6 of the fin 1.
, 7 is discontinuous.

As shown in FIG. 6, the apex angle θ2 of the top 5 of the protrusion 4 is 90°, and the intersection angle θ between the center line l of the plate thickness of the fin 1 and the protrusion 4 is
3 to 46°, the heat transfer area is approximately 1.41 times that of a flat fin in which no protrusion 4 is formed. Still, the heat flow from the heat transfer tube is roughly as shown by the arrow, and since the boundary 8a is continuous with the flat surfaces 6 and 7 of the fin 1, the heat flow to the protrusion 4 is hardly obstructed. .

On the other hand, the amount of heat transferred from the heat exchanger to the airflow side is expressed by the following equation.

Q=@A・Δt ・・・・・・・・・・・・ (1)
Here, Q: Amount of heat transfer: Heat transmission coefficient A: Heat transfer area Δt: Logarithmic average temperature difference As can be seen from equation (1), the amount of heat transfer is proportional to the heat transfer area. Therefore, as in the present invention, if the heat transfer area A is increased by providing the protrusions 4 without impeding the heat flow and reducing the heat mass flow rate K as much as possible, the heat transfer amount Q will increase and heat transfer will be promoted. It can be measured.

Furthermore, since the top portion 6 of the protrusion 4 protrudes from the flat surfaces 6 and 7 of the fin 1, it faces the direction of the airflow indicated by the arrow (■). For this reason, a heat transfer promoting effect is also obtained due to the front image effect, in which the heat transfer coefficient becomes extremely large in the front image facing the airflow.

Furthermore, since the protrusion 4 is formed by utilizing the malleability of the fin material forming the fin 1, the necessary fin material is the same as that of the flat fin, and the fin material cost will not increase by +i'li. .

Effects of the Invention As described above, according to the present invention, the heat exchanger tube passes through the fins,
By forming continuous wave-shaped protrusions in the step direction on the fins in the gaps in the step direction of the heat transfer tube, the heat transfer area per unit volume is increased, heat transfer is promoted, and a foreground effect is also achieved. Heat transfer is also promoted by the fin structure, and a heat exchanger can be obtained with the same fin cost as a conventional heat exchanger using flat fins.

[Brief explanation of drawings]

FIG. 1 is a front view of a corrugated fin of a conventional heat exchanger, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a front view of a heat exchanger fin in an embodiment of the present invention. 4 is a sectional view taken along line B7-B in FIG. 3, and FIG. 6 is an enlarged sectional view of the projection 4. 1...Fin, 4...Protrusion. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 f Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A fin of a heat exchanger, wherein a wave-shaped protrusion continuous in the step direction is formed on the fin in the gap portion in the step direction of the heat transfer tube in the fin through which the heat transfer tube passes.