带吸力面小翼的压气机叶栅变间隙特性实验

为了进一步揭示吸力面小翼在不同叶尖间隙条件下的影响机理,开展了有/无吸力面小翼的压气机叶栅变间隙特性实验.结果表明:与无间隙叶栅相比,叶尖相对间隙为1%时引入的泄漏流可以有效抑制叶片吸力面/端壁角区三维分离的产生,叶栅总损失和气动堵塞程度最低,此时为研究的4种间隙工况中的最佳间隙工况.吸力面小翼在此间隙下降低了泄漏涡强度的同时使通道涡增强,叶片吸力面重新出现了三维分离流动,叶栅总损失和堵塞程度均有所增加.在叶尖相对间隙为2%和3%时,带吸力面小翼叶栅中叶尖分离涡增强,主导叶尖区流动的泄漏涡强度减弱,两种间隙下叶栅总损失系数分别降低了8.9%和12.5%,堵塞系数分别降低了6.9%和6.3%.在研究的3种非零间隙条件下吸力面小翼降低了叶栅气动损失对叶尖间隙变化的敏感性,减弱了叶尖泄漏涡造成的叶栅出口气流角的欠偏转/过偏转程度. 

Experiment on variable tip clearance characteristics of compressor cascade with suction-side winglet

In order to further explore the effect mechanisms of suction-side winglet under different tip clearance sizes, an experimental investigation on the variable tip clearance characteristics of the compressor cascade with/without suction-side winglet was carried out. Results showed that at 1% relative tip clearance size, the tip leakage flow suppressed three-dimensional separation on the corner of suction surface and endwall, the cascade loss and endwall blockage were both minimum; and this clearance size was found to be optimum tip clearance. The suction-side winglet reduced the strength of tip leakage vortex but resulted in a stronger passage vortex, and the three-dimensional separation zone was formed again. For the particular tip clearance, the loss and endwall blockage of cascade with winglet were both higher than the baseline tip cascade. In case of 2% and 3% relative tip clearance sizes, for the cascade with suction-side winglet, the tip separation became stronger, and the strength of tip leakage vortex was reduced. In case of these two tip clearance sizes, the total pressure loss coefficients of the cascade was reduced by 8.9% and 12.5%, respectively by the suction-side winglet, and the blockage coefficients with winglet were 6.9% and 6.3% lower compared with the cascade without winglet. For these three tip clearance sizes, the compressor cascade performance sensitivity to tip clearance variation was improved by the suction-side winglet, and the degree of outlet flow angle''s underturning and overturning induced by leakage vortex was reduced by the suction-side winglet.