风机叶片表面分离涡与宽频噪声辐射特性的分析

Analysis of Separation Vortex and Broadband Noise Radiation on Fan Blade Surfaces

采用大涡模拟结合噪声FW-H模型,计算分析了低马赫数下风机Clark-Y叶型的流场结构、叶型表面压力脉动特征以及宽频噪声特征,并对表面压力脉动与远场声压的频谱进行了对比.结果表明:叶片表面形成的分离涡涡束与叶片表面压力波谷存在关联,每处分离涡对应着一个表面压力波谷;分离涡声源的远场声辐射能力极小,叶片的宽频噪声主要来源于来流冲击前缘点形成的压力脉动和尾缘涡脱落产生的压力脉动,前缘点的声辐射能力高于尾缘区域的声辐射能力.

Using large eddy simulation method and FW-H acoustic model,the flow field,surface pressure fluctuation and broadband noise radiation of a Clark-Y airfoil were analyzed under low Mach number flow conditions.Simultaneously,the spectrum of blade surface pressure was compared with that of the far field sound pressure.Results show that the near wall separation vortex has a correlation with the blade surface pressure fluctuation;each pressure fluctuation is related with a pulsating vortex.The radiation capacity at far field of separation vortex is very small,and the broadband noise mainly comes from the pressure fluctuation caused by both the leading edge impingement and the trailing edge separation;the radiation capacity at leading edge is larger than at trailing edge.