压气机“端弯”叶栅流场结构的试验研究

EXPERIMENTAL INVESTIGATION ON THE FLOW THROUGH A COMPRESSOR END-BENDING CASCADE

本文通过“端弯”和“无端弯”压气机叶栅的对比试验及流场显示 ,论述了“端弯”叶栅改善压气机端区流动和减小端区损失 (并降低沿叶高按质量平均求出的总压损失系数 )的机理。压气机“端弯”叶片的叶盆和叶背叶片力指向都有利于改善端区流动。前者将端壁区外叶盆的高能气体压向端区 ,后者将端区内叶背的低能气体送向叶中区。这是“端区”损失系数下降的主要原因之一。

By the comparison of secondary flow vector diagrams and 2-D iso-loss line diagrams between a end-bending cascade and a ordinary cascade,this paper reveal the mechanism that the end-bending cascade improves the flow through end wall region and reduces the loss of the end wall flow.At the same time,the end-bending cascade reduces the mass-averaged total pressure coefficient.Both directions of blade force on the suction and pressure surfaces are in favor of improving the end wall flow.The former pushs the high energy flow outside the end wall region near the pressure surface into the end wall region,the latter transfers the low energy flow within the end wall region near the suction surface to the main stream.The improvement of the end wall flow contributes to control the degeneration of the end wall flow downstream.