凹槽叶顶构型对涡轮转子尖区漩涡演化的影响

Effects of Squealer Tip Configuration on Vortex Evolution in Tip Region of Turbine Rotor

凹槽宽度及深度是涡轮转子凹槽叶顶造型的关键参数,为了探究这两个关键几何参数对叶尖端区的旋涡结构演化的影响规律,采用数值模拟方法,对某单级跨声速高压涡轮展开了研究。基于对平叶顶和凹槽叶顶的叶尖端区旋涡演化的深入分析,提取了该跨声速涡轮的典型流场特征。构造了6种凹槽宽度和5种凹槽深度的凹槽叶顶结构,并对典型算例进行了流场结构分析。结果表明,凹槽宽度的减小和凹槽深度的增大均会造成凹槽对泄漏流的有效阻塞范围缩小,但同时会增强该区域的阻塞效果;凹槽宽度的减小还对泄漏涡破碎起到了抑制作用;凹槽深度对涡轮级效率的影响更为显著,且存在不受凹槽宽度取值影响的最佳取值范围,约为2.5~3.0倍叶尖间隙。

The width and depth of the cavity are the key geometric parameters in the constructing process of cavity tip. To investigate the influence of these two key geometric parameters on the evolution of vortex structures in the tip region,a single-stage transonic high-pressure turbine is studied by numerical simulation. With the indepth analysis of vortex evolution in tip region of flat tip and cavity tip,the flow field characteristics of the transonic turbine are extracted. Plenty of tip configurations with 6 kinds of cavity width and 5 kinds of cavity depth are constructed. And the flow field structures of typical examples are analyzed. The results show that the decrease of cavity width and the increase of cavity depth will reduce the effective blocking range of the cavity on the tipleakage flow,but enhance the blocking effect of the blocking region at the same time. The decrease of cavity width also inhibited the tip leakage vortex breakage. The effects of cavity depth on the turbine stage efficiency are more significant,and there is an optimal range of values which are not affected by the value of cavity width,which is about 2.5~3.0 times the tip clearance.