叶片数约化对叶片气动载荷的影响研究

Investigation into Effects of Blade Sectors Scaling on the Aerodynamic Loads

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。

A 3D full Navier-Stokes method is applied to calculations of unsteady flows through a multiple blade- rows fan. The solver adopts the cell-centred finite volume discretization and the 4-stage Runge-Kutta time-marching scheme. Unsteady calculations are effectively accelerated by using a dual time-stepping scheme. Different stator blade counts are applied to simulate unsteady flow in an axial fan stage. The axial position of the shock is changed by the scaling. And the effects on the harmonies of unsteady pressure on the rotor surface are discussed. The scal- ing changed the amplitudes and locations of the main disturbances. The first harmonic of the unsteady tangential force is affected by the location of the turbulences obviously.