JPS5993191A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent the generation of a flute-like sound by a method wherein the width of a slit formed at a part of each of fins of the heat exchanger is made more than five times the width of a cavity formed between the fin and the fin adjacent thereto so that the fin and the slit does not become a mouthpiece. CONSTITUTION:The width (a) of the slit 5 formed at a part of the fin 4 is made more than five times the width (b) of the cavity 7 formed between the fin and the fin 6 adjacent thereto. With the above structure, the ratio of the thickness (h) of a filamentous air current with respect to the width (d) of the slit changes so that the sound generating rate reduces to thereby prevent the generation of the flute-like sound.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to noise reduction in heat exchangers.

[Prior art and its problems]

The conventional technology will be explained using Fig. 1. For example, a heat exchanger as shown in FIG. 1 is used to cool transistors in broadcast power amplifiers. Heat is radiated by forcing air to flow in the direction of the arrow.

FIG. 2 is a diagram illustrating the heat exchanger of FIG. 1 disassembled into member A and member B, and showing the inner surfaces of the members. A slit 2 is provided in a part of the fin 1 to disrupt the flow and increase the heat transfer coefficient.
is provided. However, this slit 2 and fin 1 functioned as a mouthpiece, and due to the principle behind the sound of a vibrator organ, a noise similar to that of a whistle was generated (hereinafter referred to as a whistling sound), which caused a problem. .

[Purpose of the invention]

The present invention improves the drawbacks of the conventional devices described above, and aims to provide a heat exchanger with less noise.

[Summary of the invention]

In a heat exchanger that performs heat exchange by forcibly flowing gas into a cavity between a plurality of fins provided oppositely, the present invention provides a heat exchanger that performs heat exchange by forcing gas into a cavity between a plurality of fins provided oppositely. The width is more than five times the width of the cavity created by other fins, and the fins and slits do not function as a mouthpiece, thereby eliminating the sound produced by the whistle from the heat exchanger.

〔Effect of the invention〕

This invention eliminates the whistling sound generated by heat exchangers,
It has the effect of reducing noise.

[Embodiments of the invention]

FIG. 3 schematically shows the sound generation mechanism.

The principle of sound production will be briefly explained using FIG.

A slit 2 provided in a part of the fin 1 serves as a reed for the whistle, and when the air flow 3 enters the slit 2, it generates a sound by causing micro-turbulent vibrations with a unique period determined by the pipe dimensions etc. .

The efficiency of sound production is determined by the thickness h of the airflow filament (if the width of the cavity created between one fin and another adjacent fin is small, the thickness of the airflow is approximately equal to the spacing1) and the width of the slit 2. It is determined by the ratio of d. According to experiments, there is a relationship shown in FIG.

Here, the horizontal axis is d/h and the vertical axis is the sound pressure level.

In other words, this sound can be reduced by changing the ratio between the thickness of the airflow (in this case, the width of the cavity) h and the width of the slit d. No matter whether cl/h is made small or large, there is a sound reduction effect. However, if d/h is made small, the effect of disturbing the flow and increasing the heat transfer efficiency becomes weak, and the provision of the slit becomes meaningless.

Therefore, the direction of increasing d/h is adopted.

An embodiment of the invention is shown in FIG. 5 and FIG. 6. FIG. 5 is an exploded view, and FIG. 6 is an assembly 7'; 7. FIG.

The width a of the slit 5 provided in a part of the fin 4 is a cavity 7 created by the fin and another fin 6 that is in contact with Fi.
A heat exchanger with a width of at least 5 times the width l) is used.

In this way, the ratio of the thickness h of the air flow filament to the width d of the slit as described above is changed, the sound production efficiency is reduced, and the whistling sound is eliminated. Moreover, the heat transfer efficiency also hardly changes.

It goes without saying that the fluid is not limited to air and may be any other gas, and the gist of the present invention does not change at all even if the fluid is a heat exchanger that absorbs heat rather than radiates heat.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional heat exchanger in an assembled state, Figure 2 is a perspective view of the conventional heat exchanger disassembled, and Figure 3 is a birch-style diagram schematically showing the sounding mechanism. Figure '54 is a characteristic diagram showing the relationship between the ratio of the cavity width to the slit width and the sound pressure level, Figure 5 is an exploded perspective view of the heat exchanger according to the embodiment of the present invention, and Figure 6 is the assembled heat exchanger. 1 is a perspective view of the heat exchanger of the present invention in a state; FIG. 4...Fin. 5...Slit, 6...Other adjacent fins. 7...Cavity, a...Width of slit, b...Width of cavity. Figure 3 1st

Claims (1)

[Claims] In a heat exchanger that performs heat exchange by forcing gas to flow into a cavity between a plurality of opposing fins, the width of the slit provided in a part of the fin is determined by the width of the slit between the fin and the adjacent fin. A heat exchanger characterized in that the width is at least five times the width of the cavity to be created.