基于时域LEE方法的发动机进气道声衬降噪优化

基于2.5D时域线化欧拉方程(LEE)和Fung的时域阻抗边界条件(TDIBC)模拟了涡扇发动机进气道风扇噪声传播并对声衬的参数进行了优化。TDIBC代码的正确性通过实验数据进行了验证。管道声模态的传播计算使用复数形式的线性化欧拉方程(LEE)在时域中实现。发动机进气道的背景流场使用Fluent软件计算,基于该背景流场并加入Fung的TDIBC模型模拟了发动机风扇噪声在进气道中的传播。提出一个有效的基于响应面替代模型的轴对称声衬的优化方法。优化的结果表明该方法可以用于降低远场声压级(SPL)的声衬优化设计。该方法对于高涵道比涡扇航空发动机声衬的降噪设计有着重要意义。

Optimal Liner Design for Aero-engine Fan Noise Propagation Using LEE and TDIBC

2.5D Linearized Euler Equations (LEE) in complex form is used to compute acoustic mode propagation in time domain. A time domain impedance boundary condition (TDIBC) proposed by Fung is coupled with surrogate-based optimization framework in the liner optimization. Data from Jones et al. is used for validation of the TDIBC implementation. A typical background flow field calculated from Fluent is used as mean flow for subsequent noise propagation calculations. An optimization process is proposed for axisymmetric liner optimization based on response surface models (RSM) method. Results showed that the optimized liner parameters can be found to maximize the far filed SPL attenuation. The study provides a useful methodology in the optimal design of more complex acoustic liners on today"s high bypass ratio turbofan engines.