一种大负荷低压涡轮叶型的气动性能

基于Lantry-Menter转捩模型,分别对Zweifel升力系数为1.2的一种大负荷低压涡轮叶型在定常来流不同湍流度、雷诺数条件下,上游非定常、周期性尾迹作用下的流动进行了数值模拟.计算结果表明,定常来流低雷诺数条件下,湍流度对该大负荷叶型的气动性能影响较大;上游非定常、周期性尾迹对叶型吸力面分离泡的抑制作用可进一步减小低雷诺数条件下的叶型损失.计算结果揭示了该大负荷叶型在低压涡轮内部真实流动环境中的表面流动及损失特征,对国内现行低压涡轮设计有着较好的启示. 

Aerodynamic performance of a highly-loaded low-pressure turbine profile

Low-pressure (LP) turbine is the main object of reducing its weight in civil high bypass ratio turbofan engine, which promotes the development of highly-loaded LP turbine airfoils. Based on Lantry-Menter transition model in Ref.6 and 7, aerodynamics of a highly-loaded LP turbine profile with a Zweifel lift coefficient of 1.2 at different freestream turbulence intensity and Reynolds numbers both under steady and unsteady inflow conditions are numerically investigated in this paper. The numerical results show that, the freesteam turbulence intensity has remarkable effects on the boundary layer flow on the profile suction surface and the profile loss at low Reynolds numbers under steady inflow conditions. At low Reynolds numbers and low freestream turbulence intensity, the unattached separation flow existing on the suction surface near the trailing edge leads to the rapid increasing of the profile loss relative to that at high freestream turbulence intensity. The suppression of the separation bubble by upstream unsteady and periodic wakes can further reduce the profile loss at low Reynolds numbers. It can be concluded that the current LP turbine design system should take into account and make well use of the truly environment characteristic of high freestream turbulence intensity in LP turbines.