涡轮动叶吸力面气膜冷却径向差异对比

Comparison for radial difference of film cooling performance on suction surface of a rotor blade

数值仿真研究了不同吹风比和旋转雷诺数条件下涡轮叶片吸力面不同叶高位置处气膜冷却效率分布的差异。研究涉及5个直径为0.8 mm的圆柱孔,气膜孔处于涡轮叶片吸力面17.8%流向位置处,并分别处于10%、30%、50%、70%和90%叶高位置处。研究在400、600 r/min和800 r/min转速下进行,分别对应旋转雷诺数357000、536000和715000。研究涉及5个吹风比:0.50、0.75、1.00、1.25和1.50。研究结果表明:靠近叶根处的气膜受叶根通道涡影响明显向叶顶方向偏转。不同叶高位置处的气膜冷却效率分布存在明显差异。旋转给冷却射流带来附加离心力和哥氏力的作用,使得吹风比和旋转雷诺数的增加对不同叶高位置的气膜尾迹偏转产生不同影响。旋转雷诺数对不同叶高位置的气膜冷却影响存在差异。

Simulations were carried out to investigate the difference of film cooling effectiveness distribution at different blade heights under different blowing ratios and rotational Reynolds numbers.Five cylindrical holes with a diameter of 0.8 mm were located at 17.8% streamwise location and at 10%,30%,50%,70% and 90% blade height,respectively.The study was conducted under three rotational speeds of 400,600 r/min and 800 r/min,correspondingly to rotational Reynolds numbers of 357000,536000 and 715000,respectively.Five blowing ratios of 0.50,0.75,1.00,1.25 and 1.50 were involved.Results showed that film trajectories in the near hub region were deflected a lot toward the tip under the effect of passage vortex.The distribution of film cooling effectiveness at different blade heights was different.Under the effect of centrifugal force and Coriolis force caused by rotation,the increase of blow ratio and rotating Reynolds number yielded different effects on film deflection at different blade heights.The effect of rotational Reynolds number on film cooling at different blade heights was different.