轴流压气机非定常数值模拟方法精度分析

Accuracy analysis of unsteady numerical simulation methods for axial flow compressor

以Stage 35单级轴流压气机为研究对象,分别用相位延迟法、叶片约化法及非线性谐波法对其进行非定常数值模拟,并与实验及半环精确非定常模拟进行对比,以分析各非定常模拟方法的计算精度。结果表明:3种非定常计算方法在对流场时均参数的预测上均能达到半环精确非定常模拟相同的精度,但几何改变使叶片约化法得到的频谱特征尤其是基频谐波幅值产生较大变化;相位延迟法虽能较准确预估基频谐波幅值,但在其余谐波处则精度通常低于叶片约化法;非线性谐波法在计算参数的非定常时域及频域特征时精度比相位延迟法和叶片约化法低。

Taking Stage 35 single-stage axial compressor as model,the predictions obtained using the nonlinear harmonic,phase lag and domain scaling method were compared respectively with the results obtained using a conventional half annulus unsteady simulation and experiment.The purpose was to analyze the numerical accuracy and computational efficiency of the three methods.Numerical results indicated that the three methods can all achieve same accuracy level as the half annulus unsteady simulation in terms of time-averaged parameters of flow field,but the spectrum characteristics obtained by domain scaling method revealed significant differences due to the geometry scaling,especially the amplitude in fundamental harmonic.The precision of the phase lag method was higher than domain scaling method in the prediction of amplitude in fundamental harmonic,however,it was usually contrary in other harmonics.Furthermore,the unsteadiness predicted by nonlinear harmonic method can not achieve the same accuracy as the phase lag and domain scaling method.