叶片数约化对叶轮机非定常气动特性影响的研究

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。计算结果给出了风扇级的性能、叶片气动载荷和非定常气动力等参数。叶片数目选择影响到非定常效率波动的幅值大小。通过对非定常气动力力的频谱分析得出,不同的叶片数目对非定常气动力的前两阶幅值造成明显的影响。

Investigation into Effects of Blade Count on Unsteady Flows in Turbomachines

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. In this article, different stator blade counts are applied to simulate unsteady flow in an axial fan stage. The results are presented of aerodynamic performance, aerodynamic loading and tangential forces. The blade count changed the amplitude of isotropic efficiency fluctuation in time. The first two harmonics of the tangential forces are significantly changed by using the scaling method.