机械通风冷却塔气动噪声的抑制研究

Research on aerodynamic noise suppression of mechanical ventilation cooling towers

目的:降低燃气电厂的机力通风逆流湿式冷却塔运行时的气动噪声。方法:针对冷却塔风扇因叶尖涡以及叶尖回流而产生的气动噪声,借助计算流体力学(CFD)和计算声学(CAA)相结合的方法对气动噪声的分布进行了数值模拟,并针对噪声源分布情况,设计了两种实验方案来减小叶顶间隙的气动噪声。结果:叶片叶尖处噪声最大为104.4 dB,而两种方案噪声A计权声压值分别降低了11.2 dBA和5.2 dBA。结论:仿真结果证实了噪声源主要分布在叶片叶尖和风筒之间;实验结果证明我们的两种方案均能有效地降低气动噪声。

Aims:This paper aims to reduce the aerodynamic noise of counter-current wet cooling towers with mechanical ventilation in gas power plants.Methods:For aerodynamic noise generated by a cooling tower fan due to tip vortex and tip reflow,bath the computational fluid dynamics(CFD) and computational acoustics(CAA) methods were used to numerically simulate the distribution of aerodynamic noise.According to the distribution of noise sources,two experimental schemes designed were to reduce the aerodynamic noise at the tip clearance.Results:The maximum noise at the blade tip was 104.4 dB.The noise A-weighted sound pressure values of the two schemes were reduced by 11.2 dBA and 5.2 dBA respectively.Conclusions:The simulation results confirm that the noise source is mainly distributed between the blade tip and the air duct.The experimental results show that both schemes can effectively reduce aerodynamic noise.