低雷诺数涡轮内部流场分析

利用三维数值模拟手段研究涡轮内部流动.对比分析了不同飞行高度工作时涡轮内部流场结构的差异,以反映雷诺数的降低对流动结构和性能的影响.结果表明:在高空工作环境下,雷诺数下降近一个量级,负荷分布发生变化,叶片吸力面发生大范围分离,二次流以及径向掺混明显增强,由此导致涡轮性能恶化,效率急剧下降,这些因素在低雷诺数涡轮气动设计中需给予更多的关注.同时指出,负荷分布形式的选择对低雷诺数涡轮设计有重要意义.

Analysis of turbine flow field under low Reynolds number condition

The flow field in turbine was investigated using three-dimensional numerical simulation method. The flow structures in different altitude were compared and analyzed, to show the effect on flow structure and turbine performance with the decrease of Reynolds number. The results indicate that on the condition of high altitude, the Reynolds number is decreased nearly one order, and the blade loading distribution is changed, large separation is found on blade suction surface, and secondary flow and radial mixing effects enhance obviously, so that the performance is changed worse and the efficiency is dropped rapidly. These factors should be paid more attention to the aerodynamic design of turbine under low Reynolds number condition. Moreover the selection of loading distribution form is also an important factor of the design.