有限厚度变截面管道噪声的数值研究

Numerical simulation of the ducted-fan noise with finite thickness

为了研究航空发动机消声短舱声传播的物理机制,采用快速声散射方法计算管道风扇远场散射问题,使用该方法不但可计算变截面管道风扇的噪声,还可计算有限厚度对声散射的影响.通过数值模拟分析了两种不同简化管道形状(等截面圆管、变截面圆管)中管道厚度对散射声场的影响,当管道厚度超过半径的2%时,管道厚度对散射声场的影响不能忽略,研究成果为声学预测中管道厚度的选择提供了参考依据.

To analyze the acoustic propagation of aircraft engine nacelle,predicting the acoustic propagation of a varying cross-section ducted-fan with finite thickness,the fast scattering method was discussed.The ability of the method in application to the sound propagation problems with different pipeline thickness of ducted-fan shapes,including the equal circular tube and variable cross-section tube has been demonstrated.If the pipeline thickness is more than 2 percents of the radius,the pipeline thickness should not be ignored in the prediction of the scattering sound field.The present method provides the theory basis for choosing the ducted-fan thickness in the engineering.