JPS6119916B2 - - Google Patents

Description

[Detailed Description of the Invention] In recent years, with the reduction in noise from air conditioners, there has been a growing tendency to design heat exchangers with front wind speeds of 1 m/s or less. Improving performance is an issue.

The present invention proposes a structure of a heat exchanger that meets the above-mentioned demands, and in particular reduces the ventilation resistance due to the dead zone following the heat transfer tube and condensed water during cooling by using the fin shape, and improves the heat transfer on the air side. This aims to significantly improve the heat transfer coefficient on the surface.

Conventionally, this type of heat exchanger is composed of a group of flat plate fins 1 arranged vertically at regular intervals and a group of tubes 2 inserted at right angles to the fin group 1, as shown in Fig. 1a, and air flows through the fins. The fluid flows in the direction of the white arrow between the tubes and exchanges heat with the fluid inside the tube. And Finn 1
As shown in Figure 1b, the thermo-fluid characteristics around the tube 2 in between are as follows: When a low wind speed airflow flows through the tube 2 in the direction of the white arrow, the angle θ from the stagnation point on the tube surface is ±70 to 80.
The flow separates at 30°, creating a dead zone 3 shown in perspective at the trailing end of the pipe.As a result, the air-side heat transfer coefficient in this dead zone 3 decreases significantly, resulting in poor heat transfer performance as a heat exchanger. It had some flaws.

The present invention solves the above problems.

A detailed explanation will be given below with reference to FIGS. 2a and 2b. FIG. 2a is a sectional view of a heat exchanger with fins showing an embodiment of the present invention, in which heat exchanger tubes 2 are inserted into fin collar portions 1a which are barred at regular intervals on the fins 1. Fin 1 around
is provided with a wave-shaped rectifying section 4 that achieves an ideal streamline shape around the heat exchanger tubes 2 and prevents separation of airflow in the low wind speed region, and the center of each heat exchanger tube 2 in the direction of adjacent stages is A water outflow groove 5 is provided in the wave-shaped rectifying section 4 that intersects the line connecting the sections. Second
FIG. 2B is a sectional view taken along the line A-A' in FIG.

When airflow flows in the direction of the white arrow in the finned heat exchanger composed of the fins 1 and the heat transfer tubes 2, the thermal fluid characteristics around the heat transfer tubes 2 are as follows. In other words, the airflow that attempts to separate when the angle θ from the stagnation point on the heat transfer tube surface is ±70 to 80 degrees is prevented from separation by the wave-shaped rectifying section 4 provided over the fins 1 around the heat transfer tube 2, and the air flow is prevented from being separated. Since the fluid flows along the surface of the heat transfer tube 2, the dead area 3 downstream of the heat transfer tube 2 is significantly reduced. Therefore, even in the downstream region of the heat exchanger tubes 2, sufficient heat exchange between the heat exchanger tubes 2 and the airflow can be performed, so that the heat transfer performance of the heat exchanger is significantly improved.

In addition, the wave-shaped rectifying section 4 realizes an ideal streamline shape around the surface of the heat transfer tube 2 and prevents separation of the airflow, so that the airflow passes between the fins 1 without disturbing the airflow. Airflow pressure loss can be reduced.

Furthermore, when the heat exchanger is used as a cooler, the condensed water generated near the heat exchanger tubes 2 on the surface of the flat fin 1 falls, and the waveforms on the lower side of the heat exchanger tubes 2 fall in the direction of gravity of the wave-shaped rectifier 4. It flows along the shape rectifying section 4,
Since the wave-shaped rectifier 4 has a substantially arc shape that is almost concentric with the heat exchanger tube 2, the condensed water flows toward a place where the angle θ from the stagnation point on the surface of the heat exchanger tube 2 is approximately 90 degrees, and the water flows into the water outflow groove. It flows out from 5. Therefore, even when used as a cooler, the air flow path formed by the wave-shaped rectifier 4 is not blocked by condensed water.
Because airflow passes through it, heat transfer performance can be greatly improved without increasing ventilation resistance, as well as heat dissipation properties.

In this embodiment, the cross-sectional shape of the rectifier 4 is a fixed tooth shape, but it is clear that other shapes, such as a groove shape, will have the same effect.

As described above, the present invention is composed of a group of fins arranged in parallel at regular intervals and two groups of heat exchanger tubes inserted at right angles to the group of fins, and air flows through the first group of fins around the two groups of heat exchanger tubes. A finned heat exchanger is provided with a wave-shaped rectifier 4 to prevent separation of the heat exchanger tubes 2, and a water outflow groove 5 is provided in the wave-shaped rectifier 4 that intersects with a line connecting the centers of adjacent stage heat transfer tubes 2. Since it is a heat exchanger tube 2, it is possible to reduce the dead zone 3 downstream of the heat exchanger tube 2, prevent separation of the airflow on the surface of the heat exchanger tube 2, and reduce the pressure loss of the airflow passing between the fins 1 without disturbing the airflow. The heat transfer performance of the heat exchanger is greatly improved.

Furthermore, when used as a cooler, the airflow passage formed by the wave-shaped rectifier 4 is not blocked by condensed water and the airflow flows, so that the ventilation resistance as well as the heat dissipation characteristics are increased. It is possible to significantly improve heat transfer performance.

Furthermore, since the wave-shaped rectifying section 4 and the water outflow groove 5 are symmetrical with respect to the line connecting the centers of the heat transfer tubes 2 arranged in the step direction, the heat transfer is the same regardless of whether the airflow flows from the forward or reverse direction. It has many features such as maintaining performance and eliminating errors during installation.

[Brief explanation of the drawing]

Figure 1a is a perspective view of a conventional heat exchanger, Figure 1b
is the thermo-fluid characteristic diagram around the pipe between the fins, Figure 2a
2 is a cross-sectional view of a heat exchanger with fins showing an embodiment of the present invention, and FIG. 2b is a cross-sectional view taken along line A-A' in FIG. 2a. 1...Fin, 1a...Fin collar part, 2...
... Heat exchanger tube, 3 ... Dead area, 4 ... Wave shape rectifier,
5...Water outflow groove.

Claims (1)

[Claims] 1 Consists of a group of fins arranged in parallel at regular intervals and a group of heat transfer tubes inserted at right angles to the group of fins and arranged in a staggered manner, and prevents separation of airflow to the group of fins around the group of heat transfer tubes. A heat exchanger with fins, wherein a wave-shaped rectifying section is provided, and a water outflow groove is provided in the wave-shaped rectifying section that intersects a line connecting the centers of heat exchanger tubes in the direction of adjacent stages.