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通过求解三维非定常N-S方程模拟叶轮机械内部流场。采用有限体积中心差分和四步龙格库塔时间推进格式,并且使用了双时间方法对计算加速。对一级跨音速风扇静叶选取不同的叶片数方案进行了非定常流场和性能数值模拟。对于不同的叶片数,叶片几何截面按比例缩放以保证各方案叶片稠度不变。通过对特征截面时均载荷的分析研究了静叶约化对下游激波位置的影响。通过对流面参数的快速傅里叶变换,分析了约化对动叶表面静压各阶谐波幅值的影响。研究发现,约化改变了动叶表面主要非定常载荷的幅值以及轴向位置。而轴向位置的改变对非定常气动力的一阶谐波幅值产生了显著的影响。
The flow field inside the impeller is simulated by solving the three-dimensional unsteady N-S equation. The finite volume center difference and the four-step Runge-Kutta time-lapse format were used and a two-time method was used to accelerate the calculation. The unsteady flow field and the numerical simulation of the performance of a transonic fan with different blade numbers were carried out. For different numbers of blades, the geometric cross-section of the blades is scaled to ensure the consistency of the blades of each scheme. The effect of static vane reduction on the location of downstream shock wave was studied by analyzing the average load at the characteristic cross section. Through the fast Fourier transform of the convection surface parameters, the influence of reduction on the magnitude of each harmonic of hydrostatic pressure at the moving blade surface is analyzed. The study found that reduction reduces the magnitude and axial position of the major unsteady loads on the rotor blade surface. The change of axial position has a significant influence on the first harmonic amplitude of unsteady aerodynamics.