JPH0229597A - Heat exchanger - Google Patents

Abstract

PURPOSE:To obtain a heat exchanger improved in the heat transfer performance thereof by a method wherein the heat exchanger is constituted of wavy fins, arranged in parallel and the flow of air flows therebetween, and heat transfer tubes, inserted into the wavy fins orthogonally thereto and liquid flows therethrough, while connecting slanted surfaces between the wavy parts of the wavy fins and flat parts around the collars of the fins are provided with cut-and-raised parts. CONSTITUTION:In a heat exchanger employing wavy heat transfer fins, the leading edge effect of boundary layer is generated in the flow of air, flowing along connecting slanted surfaces 15, by the cut-and-raised surfaces of cut-and-raised parts 16 while a part of the flow of air flows through the holes of the cut-and-raised parts to the peripheries of heat transfer tubes in a neighboring space partitioned by the fins. The flow of the inflow air 17 is mixed with the flow of air 18 flowing along the connecting slanted surfaces in the neighboring space and the condition of turbulent flow is generated whereby the heat transfer rate of the surfaces of the fins may be improved and a dead water area 19 after the heat transfer tubes may be reduced since the turbulent flow flows into the directions of the heat transfer tubes. The leading edge effect of boundary layer, the improvement of the surface heat transfer rate of the fin due to turbulent flow effect and effective reduction of the dead water area after the heat transfer tube may be obtained more effectively compared with a heat exchanger obtained so far.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat exchanger that transfers heat between a refrigerant and a fluid such as air, which is widely used in refrigeration equipment and air conditioning equipment.

Conventional technology In recent years, there has been a demand for higher efficiency in equipment, and there is an urgent need to improve the efficiency of heat exchangers used in refrigeration equipment and outdoor units of air source heat pumps, which are prone to frost formation on heat exchangers. be.

An example of a conventional heat exchanger will be described below with reference to the drawings. 4, 6 and 6 show conventional heat exchangers. FIG. 4 is a perspective view of a heat exchanger, and 1 is a large number of heat fins arranged in parallel. A heat transfer tube 2 is inserted into the heat transfer fin 1 at right angles. 6 is a plan view of the heat transfer fin 1, and FIG. 6 is a sectional view of the heat transfer fin 1.

Air flows between the heat transfer fins 1, and refrigerant flows within the heat transfer tubes 2 to exchange heat.

@The surface of the heat fin 1 is formed into a wavy shape in order to improve the heat transfer coefficient, but in order to form the collar 3 into which the heat transfer tube 2 is inserted, a flat part 4 and a wavy part 6 are formed on the rotation of the collar 3. and a connecting slope 6 between the flat portion 4 and the flat portion 4.

Problems to be Solved by the Invention In order to improve the performance of heat transfer fins, it is necessary to
It is advantageous to increase the peak length L between the heat transfer tubes. This is due to the increased turbulence of the air flowing between the heat transfer fins, and the resistance of the peaks located downstream of the heat transfer tubes, which causes the air to flow to the back of the heat transfer tubes, reducing the dead area 7 of the flow. Because it can be done. However, with the recent demand for cost reduction, when trying to make the material of the heat transfer fins thinner, the material breaks, making it impossible to increase the height H of the undulating fins, and making the ridges between the heat transfer tubes longer. L can't be too long either. Therefore, the air flow 8
turbulence is small, and the dead area 7 at the rear of the heat transfer tube is also not small, resulting in poor heat transfer performance.

In view of the above-mentioned problems, the present invention aims to improve heat transfer performance without increasing the height of the undulating peaks and without increasing the length of the peaks between the heat transfer tubes too much.

Means for Solving the Problems A large number of heat exchangers of the present invention are arranged in parallel at regular intervals,
Consisting of wavy fins through which air flows, and heat transfer tubes inserted perpendicularly into the wavy fins through which fluid flows, the wavy fins are cut and raised on the connecting slope between the wavy part and the flat part around the collar. It was established.

Function: Due to the cut-and-raised surface provided on the connecting slope, the airflow flowing along the connecting slope collides with the cut-and-raised surface, and then a part of the airflow passes through the cut-and-raised hole and flows into the adjacent space across the fins. It flows into the heat transfer layer.

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

FIG. 1 is a plan view of heat transfer fins constituting a heat exchanger in an embodiment of the present invention. 12 is a wavy portion whose surface is formed into a wavy shape to improve heat transfer coefficient; 13 is a collar for inserting a heat exchanger tube; 14 is a flat portion provided around the collar 13; and 16 is a wavy portion 12 and a flat portion 14. 16 is a cut and raised connection slope provided on the connection slope 16, 17
18 is the airflow blowing out from the hole in the raised cut 16, 18 is the airflow flowing on the connecting slope, and 19 is the dead area at the rear of the heat exchanger tube.

Further, FIG. 2 is a detailed view of the cutting 9 and raising 16 in FIG.

In the heat exchanger using the wavy heat transfer fins as described above, the airflow flowing along the connection slope 15 is caused by the cut and raised fins 16.
The cut-and-raised surface generates a boundary layer leading edge effect, and a portion of the airflow flows from the cut-and-raised hole into the vicinity of the heat transfer tube in the adjacent space, separating the fins. The inflowing airflow 17 mixes with the airflow 18 flowing along the connecting slope of the adjacent space and becomes turbulent, improving the fin surface heat transfer coefficient, and flowing in the direction of the heat exchanger tube, reducing the dead area 19 at the rear of the heat exchanger tube. .

As described above, this embodiment is effective in improving the fin surface heat transfer coefficient due to the boundary layer leading edge effect and turbulence effect and reducing the dead area at the rear of the heat exchanger tube, compared to the conventional heat exchanger. Therefore, using FIG. 3, the heat transfer performance of the heat exchanger of this embodiment and a conventional heat exchanger will be compared. In Fig. 3, the vertical axis QA/QB is the heat exchange capacity @B of the heat exchanger using the conventional wavy heat transfer fins and the heat exchange capacity OA of the heat exchanger using the wavy heat transfer fins of this embodiment. UF on the horizontal axis indicates the wind speed in front of the heat exchanger. The specifications of both heat exchangers are exactly the same except for the presence or absence of cut and raised parts, and the experimental conditions are also the same. As shown in Figure 3, the practical wind speed range is 1 m/s.
In the vicinity, the heat exchanger of this embodiment can improve the heat exchange capacity by 15% compared to the conventional heat exchanger.

Effects of the Invention As described above, the heat exchanger of the present invention has a cut-and-raised part on the connecting slope between the wavy part of the wavy fin and the flat part around the collar, thereby reducing the fin surface due to the leading edge effect of the boundary layer and the turbulent flow effect. It is effective in improving the heat transfer coefficient and reducing the dead zone at the rear of the heat exchanger tube, thereby realizing an excellent heat exchanger with improved thermal performance.

[Brief explanation of the drawing]

Fig. 1 is a plan view of heat transfer fins of a heat exchanger according to an embodiment of the present invention, Fig. 2 is a detailed view of the cut and raised portions in Fig. 1, and Fig. 3 is a diagram showing a heat exchanger according to an embodiment of the present invention and a conventional A comparison diagram of heat transfer performance with a heat exchanger, Figure 4 is a perspective view of a conventional heat exchanger, Figure 5 is a plan view of a conventional heat transfer fin, and Figure 6 is a cross-sectional view of a conventional heat transfer fin. be. 1...Heat transfer fin, 2...Heat transfer tube, 1
2... Group/wavy part, 13... Color, 14...
... Flat part, 16 ... Connection slope, 16 ...
...Cut up, 17.18...Airflow. Name of agent: Patent attorney Shigetaka Awano and 1 other person Figure 12- By case

Claims (1)

[Claims] It consists of a large number of heat transfer fins arranged in parallel at regular intervals, through which air flows, and heat transfer tubes inserted at right angles to the heat transfer fins, through which fluid flows, and the wavy portions of the heat transfer fins and A heat exchanger characterized by providing a cut and raised slope on the connecting slope with the flat part around the collar.