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采用薄壁边界元/FW-H理论混合方法建立了考虑薄壁声学散射效应的数值计算模型。这种声学计算模型可以预测存在薄壁如风扇机匣、蜗壳等条件下的声波的传播及散射问题。计算模型的建立主要包含噪声源的计算和声源的传播两方面:首先建立FW-H的频域方程,并采用计算流体力学方法计算流场,通过流场数据计算气动噪声源;然后采用薄壁面边界元法计算固壁对声波的散射,并计算声波在固壁散射后的声场分布。数值计算结果和实验结果及经典的叶轮机管道风扇噪声理论进行了对比,结果表明,这种计算模型与理论计算结果及实验结果吻合较好,可以准确的预测机匣壁的散射效应对声源传播的影响。
A thin-walled boundary element / FW-H theory mixing method is used to establish the numerical calculation model considering the thin-wall acoustic scattering effect. This acoustic calculation model can predict the existence of thin-walled fan casing, volute and other conditions of the sound wave propagation and scattering problems. The calculation model mainly consists of the calculation of noise source and the propagation of sound source. Firstly, the frequency domain equation of FW-H is established, and the flow field is calculated by computational fluid dynamics method, and the aerodynamic noise source is calculated by flow field data. Wall boundary element method to calculate the solid wall scattering of sound waves, and calculate the sound field in the solid wall scattering sound field distribution. The numerical results and experimental results are compared with the classical theory of turbine duct fan noise. The results show that the calculation model is in good agreement with the theoretical calculation and experimental results, which can accurately predict the scattering effect of the casing wall on the sound source The impact of communication.