翼身融合飞机发动机进气道声衬优化设计

The Optimization of Inlet Liner for Blended Wing Body Aircraft with Back-Supported Engine Layout

针对背撑式发动机布局的翼身融合体飞机进气道声衬开展空间布局优化设计。在频域内求解Mohring声类比方程,通过声模态模拟风扇噪声源,以无反射边界模拟声学远场;特别的考虑了进气道沿垂直面对称的特性,采用对称-反对称边界条件,通过2.5维的求解提高了计算量,数值仿真的精度通过了与国际上公开的试验结果的对比。以降低进气道向机体表面的噪声辐射为优化目标,以进气道内沿轴向和周向布局声衬的声阻和声抗为设计变量,开展了声衬空间布局优化设计。优化结果表明,空间布局的声衬大幅度降低短舱进气道向外辐射的噪声的同时改变了短舱的向外噪声辐射特性,相比于向天空辐射的噪声,向机体表面辐射的噪声低10dB。空间优化布局的进气道声衬可显著改变噪声的指向特性。

This article takes the optimization of inlet liners for blended wing body aircraft with back-supported engine layout.The Mohring acoustic analogy equation is solved in the frequency domain,the fan noise source is simu-lated through the acoustic mode,and the acoustic far field is simulated with a non-reflective boundary;in particular,the symmetrical characteristics of the inlet along the vertical plane are considered,and the symmetric-antisymmetric boundary condition is adopted.The 2.5-dimensional solution increases the amount of calculation,and the accuracy of the numerical simulation has passed the comparison with the experiment results published internationally.The article takes the reduction of the noise radiation of the inlet to the surface of the airframe as the optimization goal,and takes the acoustic resistance and reactance for the acoustic liner arranged in the axial and circumferential directions in the inlet as the design variables,and develops the optimization design of the acoustic liner space layout.The optimization results show that the acoustic liner of the space layout greatly reduces the noise radiation from the nacelle inlet,and effectively changes the noise radiation characteristics of the nacelle.Compared with the noise radiation to the sky,the noise radiation to the airframe is effectively changed.The noise radiated by the surfaced is 10dB lower.The spatially optimized acoustic liner of inlets can significantly change the noise directivity.