高负荷扩压叶栅二维非定常数值模拟

Two dimensional unsteady numerical investigation in a highly loaded compressor cascade

为探究高负荷扩压叶栅在大正冲角下的非定常流动机理,应用数值方法与拓扑分析理论考察了大正冲角下叶栅内分离旋涡的发展过程,并分析了旋涡运动对流场参数的影响.结果表明,+15°冲角下叶栅内主要存在吸力面分离涡和尾缘涡,吸力面分离涡的脱落频率为104.7 Hz,尾缘涡和吸力面分离涡交替脱落形成两倍频211.5 Hz;分离涡在发展过程中会抑制和归并弱小旋涡,同时还会使叶片的局部气动负荷明显上升.

In order to explore the mechanism of unsteady flow in a highly loaded eompressor cascade with large positive inci- dence ,the separation vortices evolution and the effect of the vortices on flow field parameters were analyzed and discussed with the topological analysis and numerical simulation method. Results show that there are two kinds of vortices in cas- cade passage at incidence of ＋ 15° ,suction surface separation vortex and trailing edge shedding vortex. The vortex-shedding frequency of suction surface separation vortex is 104.7 Hz. The double frequency 211.5 Hz is caused by the alternative shedding of trailing edge shedding vortex and suction surface separation vortex. During the development process of the separation vortex, it may restrain and merge puny vortices. Mean- while the separation vortex makes the aerodynamic loading of blade rise obviously.