叶尖单侧倒圆对扩压叶栅叶顶间隙流动的影响

提出了一种控制扩压叶栅叶顶间隙流动的方法,通过对叶尖压力面小尺度的倒圆修型,改善了扩压叶栅叶顶间隙流动状况。通过数值模拟方法研究叶尖倒圆结构对扩压叶栅性能的影响及作用机理,并探究3种不同倒圆半径(约为3%、4%、6%的叶片最大厚度)叶尖倒圆结构的流动控制效果。结果表明:叶尖倒圆能够削弱叶尖分离涡,进而影响叶尖流场不同涡系之间的相互作用,使得叶顶间隙通道附近的总压损失减少;但是叶尖倒圆半径越大,泄漏流流量越大,会加剧泄漏流与主流的掺混,使总压损失增加。因此合适的叶尖倒圆半径能够使叶栅性能得到最大程度的改善。此外,在倒圆半径为3%叶片最大厚度时,叶栅在较大的攻角范围内均获得了良好的改善损失的效果。

Effect of unilateral blade tip fillet structure on blade tip clearance flow of compressor cascade

A method of compressor cascade blade tip leakage flow control was presented. By using a small-scale fillet structure in the pressure side of the blade tip region, the flow condition in the tip clearance of the diffuser cascade was improved.The effects of blade tip fillet on the aerodynamic performance of compressor cascade were investigated by numerical method. Through analysis of the control effects of three different tip fillet structures (3%, 4%, 6% of the maximum blade thickness), the simulation showed that the blade tip fillet structure can weaken the tip separation vortex with the decrease of total pressure loss coefficient of tip clearance passage and affect the vortex system structure in the region of tip clearance. The method showed a good ability to improve the flow conditions in the blade tip region and undermined the effect of blockage in blade tip passage. However, an increase in the leakage mass flow rate with a loss for the efficiency was observed because of the mixing of leakage flow and main flow. The conclusion shows that the appropriate blade tip fillet structure could improve the aerodynamic performance and the fillet radius of 3% of the maximum blade thickness has a good effect compared with other radiuses.