分流叶片位置对高转速离心压气机性能的影响

运用三维粘性流动数值计算程序FineTM/Turbo对叶顶间隙泄漏存在时带分流叶片的高转速离心压气机模型级内部流动进行了数值模拟,重点分析了分流叶片不同起始位置及不同周向位置对压气机级内三维粘性流场及整级性能的影响.计算中采用Jameson的中心差分格式结合Baldwin-Lomax代数模型使用时间推进法求解雷诺平均N-S方程,计算模拟了模型级内部复杂的三维粘性流动过程及气体参数分布的详细结构和规律.计算结果表明:采用分流叶片在进口段会减少叶片阻塞,从而使更高的质量流量可以流经叶轮;分流叶片起始位置位于Ⅲ时,两个通道叶轮出口处速度分布最均匀;分流叶片越短,长叶片压力面无量纲静压载荷越大.当分流叶片长度达到某一数值后,长叶片载荷变化趋于平缓.分流叶片位于不同周向位置时,IBSA叶轮的模型级效率最高,压气机性能最好.

Effect of the splitter blade position on the characteristic of high-speed centrifugal compressor

The time marching method is used to solve the control equations and a computational analysis of the flow field in a unshrouded centrifugal impeller is presented. Emphasis is focused on the effect of splitter blade distribution on the flow field and characteristic of the impeller. The numerical analysis is carried out using three-dimensional Navier-Strokes codes with the Baldwin-Lomax algebraic model for closure. The calculations are performed with a central space discrimination scheme, with second and fourth order artificial dissipation terms. The numerical procedure applied a four-order explicit Runge-Kutta scheme, coupled to local time stepping. Numerical results show the blockage at the inlet reduces using the splitter blade. It can get more uniform distribution of the velocity at the impeller outlet when the splitter blade is at location III. The load at the blade pressure side becomes heavier with the shorter splitter blade. For the different azimuthal distribution of splitter blade, impeller IBSA has the highest efficiency.