燃气轮机1.5级轴流压气机气动噪声预测

Aerodynamic noise prediction of the 1.5-stage axial compressor of a gas turbine

针对多排叶片旋转机械气动声源的复杂性,本文研究了一种预测多排叶轮气动噪声的数值模拟方法。基于混合计算方法研究了燃气轮机1.5级压气机的气动噪声特性,采用剪切应力传输湍流模型对1.5级轴流压气机的三维非定常流场进行全通道计算并获得声源,基于变分形式的Lighthill声类比耦合声源信息预测了压气机噪声,并在压气机动态实验台开展了流场和噪声实验研究。结果表明:非定常压力脉动傅里叶变换后峰值主要出现在叶片通过频率及其谐波处,且压力幅值随着叶频阶数的升高而降低;前传噪声有明显的声学指向性,具有明显的偶极子特征,离散噪声包含可传播的高阶模态;数值仿真的结果与实验吻合较好,本文研究的数值计算方法对多排叶轮的气动噪声预测具有较高的精度。

Aiming at the complexity of the aerodynamic sound source of the multi-row blade rotating machinery,we developed a numerical simulation method for the aerodynamic noise of a multi-row impeller.The aerodynamic noise characteristics of the 1.5-stage compressor of the gas turbine were studied based on the hybrid calculation method.The shear stress transport turbulence model was used to calculate the three-dimensional unsteady flow field of the 1.5-stage axial compressor,obtaining the sound source.Then,the compressor noise was predicted based on the Lighthill acoustic analogy coupling sound source information in the variational form,and experimental research on the flow field and noise was performed on the compressor dynamic test bench.The results show that the unsteady pressure pulsation peak after a Fourier transform mainly appeared at the blade pass frequency and its harmonics,and the pressure amplitude decreased with the increase in the blade frequency order.The forward noise had obvious acoustic directivity and dipole characteristics,and discrete noise contained high-order modes that can be propaga-ted.The numerical simulation results are in good agreement with the experimental results.The numerical calcula-tion method developed in this work has high accuracy in predicting the aerodynamic noise of multi-row impellers.