机匣喷气量对涡轮间隙流动控制的影响

采用数值模拟方法研究机匣喷气量大小对涡轮间隙流动控制的影响。结果显示，在10％轴向弦长位位置喷气时，增大喷气量，喷气在间隙内轴向上影响范围增大，对间隙流阻塞作用增加，间隙涡出现位置推迟。同时减小了间隙涡、上通道涡区熵增，尤其是上通道涡区损失大幅减小，并减弱机匣喷气引起的气流偏转不足／过偏现象。叶顶压力面附近由间隙流动引起的低压区减小，并向叶片尾缘移动。但由于喷气量增大使得动叶输出功率下降，使得涡轮效率降低。

Effects of casing air injection massflow rates on controlling tip clearance flow in axial turbines

This paper presents a numerical investigation of the influence of casing air injection massflow rates on controlling secondary flow around rotor tip regions. It shows that with injection at 10% axial chord, as injection massflow rate increases, the axial influence range inside tip clearance extends, delaying the inception of tip clearance vortex axially. Furthermore, losses of tip clearance vortex and tip passage vortex reduce remarkably, especially those induced by tip passage vortex. The low - pressure zone caused by tip clearance flow on blade tip surface decreases and moves towards the trailing edge. Although increased injection massflow reduces secondary losses, turbine efficiency declines because rotor work output decreases more significantly.