球窝抑制层流分离的大涡模拟研究

The Large-eddy simulations were performed to investigate the mechanism of laminar separation control in a highly-loaded low-pressure turbine cascade with recessed dimples and a quasi-2D U-groove. The results show that a periodic shedding vortex is induced by the recessed dimple. The shedding vortex accelerates the formation and the breakdown of span-wise vortices, which indicates an earlier transition of the laminar boundary layer. As a result, the separation is inhabited significantly. At a condition of Reynold Number 45000, the total pressure loss is reduced by 25.4% via recessed dimple. Moreover, compared with the U-groove, the three-dimensional dimples could accelerating the transition process more effectively, and thus have a better performance in separation flow control.