射流襟翼-低压涡轮叶栅主动流动控制数值研究

Numerical study of active flow control using jet-flap for a low-pressure turbine cascade

针对PAK-B低压涡轮叶型,基于耦合了Langtry-Menter转捩模型的Menter’s SSTk-ω两方程模型,数值研究了不同流动状态下射流襟翼的流动控制机理.计算结果表明,射流襟翼能够有效控制PAK-B叶型失速流动状态下的损失,当射流流量百分数为2%,能量损失系数较无射流襟翼控制状态时下降40%;同时,气流转折角增大5%;影响并使主流进口质量流量减小10%,对于叶型未失速流动,控制不一定有效.结果还表明,射流襟翼能够推迟相邻叶型吸力面边界层转捩,从而延迟分离流动再附.

Based on Menter＇s SST κ-ε turbulence model coupled with Langtry-Menter transition model, the control mechanism of jet-flap, an active flow control method for PAK- B low-pressure turbine blade profile, was numerically investigated under different flow conditions including different cascade inlet Reynolds numbers, free stream turbulence levels, and cascade outlet Mach numbers. The results show that the jet-flap effectively reduces flow loss when PAK-B profile is stalled. With jet flow mass fraction equal to 2%, relative to the baseline, the energy loss coefficient reduced by about 40% ; the flow turning angle increased by about 5% ;and the inlet primary flow mass reduced by about 10%. When the flow was not stalled, the control could be ineffective. The results also show that the jet-flap delays boundary layer transition on adjacent blade profile suction side, which in turn delays the boundary layer reattachment.