关键词: 涡轮叶栅;端壁+;二次流;气体喷射;薄膜冷却;喷射角+

Abstract: Detailed aerodynamic measurements were carried out in the passage of a large-scale low speed turbine cascade with single row injection on the endwall upstream of leading edge. Full velocity contours and secondary flow velocity vectors were obtained with coolant injection at blowing ratio 1, 2, 3 and injection angle 25°, 35°, 45°, respectively. The corresponding kinetic energies of secondary flow were also determined. The influences of injection angle on the aerodynamic aspects of endwall film cooling and on the secondary flow vortex structures in the near endwall region of the passage were studied. The results reveal that the strength and the size of passage vortex could be reduced by decreasing injection angle. It was observed that the cores of coolant jets could stay closer to endwall by decreasing injection angle, but the flow velocity in the neighborhood of endwall increases remarkably as well. At high blowing ratio, the capability of transporting coolant to the pressure side at injection angle 35° is greater than that at injection angle 25° and 45°.

Key words: Turbine cascade;Endwall~+;Secondary flow;Gas injection;Film cooling;Injection angle~+