气动－声学风洞热交换器的气动噪声研究

A Study on Aero-noise of Heat Exchanger in Aero-acoustic Wind Tunnel

摘要:

气动-声学风洞选用阻力小、换热性能好的矩形翅片椭圆管热交换器。为了评估该热交换器的声学性能，本文使用传声器在模型风洞分别测量5个风速下热交换器进出口声学特性。通过实验发现，热交换在所测量风速下，自身产生的气动噪声大小约为8.9～10.7dB，其能量主要集中在中低频。相同管排数下漩涡脱落频率随迎面风速呈线性增加表明，对于给定热交换器存在1个不变的斯托拉哈尔数。

Abstract:

Rectangular steel finned elliptical tube heat exchanger with low pressure loss and good heat transfer performance is used at Aero-acoustic Wind Tunnel. In order to estimate the acoustic performance of the heat exchanger, microphones are used to test the acoustic performance of the heat exchanger inlet and outlet at a model wind tunnel in the present study. The test results show that the difference of total sound pressure level between heat exchanger inlet and outlet is almost 8.9~10.7dB at five test velocities, and the frequency of aero-noise generated by heat exchanger is mainly in the low and middle frequency range. Further discussion shows that with increasing in the upstream flow velocity, the frequency of shedding vortex increases linearly, suggesting the existence of a constant Strouhal number for a given heat exchanger.