基于混合数值算法的锯齿形喷管气动噪声仿真

Aerodynamic Noise Simulation of Chevron Nozzle Based on Hybrid Numerical Method

为了预测航空发动机喷流噪声远场声压级,满足未来的航空器噪声适航要求,采用计算流体力学(CFD)和计算航空声学(CAA)混合数值算法,对安装Chevron型锯齿的喷管进行气动噪声仿真计算。使用大涡模拟(LES)计算喷管的瞬态喷流流场。在流场计算的基础上使用Ligthill声类比进行声源提取,结合有限元/无限元方法对喷流噪声近场/远场的辐射特性进行仿真计算及分析,并将喷流噪声的数值仿真结果与实验值进行对比验证。数值仿真结果表明,混合数值计算方法的计算结果与实验所测远场声压级基本吻合,可以用于喷流噪声的预测。

In order to predict the far-field sound pressure level of jet noise of aeroengines, and meet the airworthiness requirements of aircraft noise in the future, the aerodynamic noise of the Chevron serrated nozzle was simulated by a hybrid numerical algorithm of computational fluid dynamics( CFD) and computational aeroacoustics(CAA). The nozzle’s transient jet flow field was calculated using large eddy simulation(LES). Based on the calculation of the flow field, the sound source was extracted by using Ligthill sound analogy, and the radiation characteristics of the near-field/far-field of the jet noise were simulated and analyzed by combining the finite element/infinite element method. The numerical simulation results were compared with experimental values to verify. Numerical simulation results show that the calculation results of the hybrid numerical calculation method are basically consistent with the far-field sound pressure level measured in the experiment, and can be used to predict the jet noise.