端壁凹坑深度对跨声速涡轮叶栅损失特性影响的数值研究

Numerical research on effects of end-wall dimples depth on loss performance of transonic turbines cascade

采用仿生学球形凹坑表面结构被动控制方法,探究5种深度的凹坑方案,其深度分别为0.10 mm、0.15 mm、0.20 mm、0.25 mm和0.30 mm,深径比均为0.25,三排凹坑被布置在18%~30%弦长处,其中距叶片吸、压力面均为2 mm,轴向间距为4 mm。研究对象为由1+1/2高压级跨声速对转涡轮构成的平面叶栅,通过商用CFD模拟计算得出损失系数、静压分布等气动指标,分析在端壁位置布置不同深度凹坑对涡轮叶栅流动性能的影响。数值结果显示:0.2 mm深度的端壁凹坑对流道内涡系发展具有最优的流动控制效果,抑制了横向二次流沿展向爬升,削弱了端区附近激波强度,使叶栅总压损失系数降低2.71%。

The passive control method of bionics dimple surface structure was adopted to explore five dimple schemes with different depths, which were 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm and 0.30 mm respectively. The depth diameter ratio was 0.25, and three rows of dimples were arranged at 18%~30% chord length, in which the distance from the suction and pressure surfaces of the blades was 2 mm, and the axial spacing was 4 mm. The research object was the plane cascade composed of 1+1/2 high pressure transonic turbine. The aerodynamic indexes such as loss coefficient and static pressure distribution were obtained by commercial CFD simulation, and the influence of different depth pits on the flow performance of turbine cascade was analyzed. The numerical results show that the 0.2 mm deep end wall pit has the best flow control effect on the development of vortex system in the channel, inhibits the lateral secondary flow climbing along the spanwise direction, weakens the shock intensity near the end zone, and reduces the total pressure loss coefficient of the cascade by 2.71%.