轴流风叶降噪机理及优化分析

为了降低轴流风叶的气动噪声,提高轴流风叶及其系统的气动性能,探究轴流风叶气动噪声产生的根本原因和内流场降噪的机理,寻找一种较为有效的降噪方案,以一款空调用轴流风叶为模型,针对风叶尾缘处进行结构参数化设计,提出了3种轴流风叶尾缘优化方案,并对各方案的内流场进行数值模拟分析,同时引用BVF(边界涡量流)诊断方法对仿真结果进行对比分析,最后通过试验进行验证,探究了轴流风叶涡流噪声的产生机理和有效解决涡流噪声的降噪方案。结果表明:边界涡量流诊断技术可用于分析诊断产生涡流的根源,通过涡量变化及内流场分布差异探究内部复杂流动机理是一种可行的仿真方案;风叶尾缘的旋涡流是产生涡流噪声的根本原因,通过减少叶尾涡流的尾缘锯齿方案能有效降低轴流风叶涡流噪声;提出了尾缘降噪的结构尺寸设计参考,为后续气动噪声的降噪研究提供一定的参考依据。

Noise reduction mechanism and optimization analysis of axial flow fan

To reduce the noise of the axial fan and improve its aerodynamic performance, the causes of the noise and the mechanism of noise reduction in the internal flow field were studied. Three approaches were proposed to optimize the design of the blade trailing edge. All the approaches were carried out via modeling and simulation of an axial fan blade. The diagnostic method of boundary vorticity flux (BVF) was used to analyze the results of the simulation, which were verified by experiments. The results show that the diagnostic method of BVF can be used in analyzing the cause of the eddy. It is an efficient way to investigate the mechanism of the internal flow based on the variation of the eddy and the distribution of the internal flow field. The eddy in the blade trailing edge is the main reason of the noise, and the serrated trailing edge approach, which can reduce the eddy in the blade trailing edge, can significantly reduce the noise. In addition, a reference structure of the trailing edge is proposed, which can make a contribution in the reduction of the aerodynamic noise.