轴流压气机近失速工况下轴向间隙对径向流影响的研究

Effect of Axial Clearance on Radial Flow in Axial Compressor Near to Stall Condition

为研究导叶和动叶轴向距离对动叶径向流动的影响,对1.5级压气机模型进行数值模拟。对不同导叶和动叶间轴向间隙的计算表明,动叶角区径向流随着流量的降低逐渐向叶顶发展,同一流量时,轴向间隙小的动叶径向流上升高度更大,其在不同高度随时间的径向波动幅度也较强。导叶/动叶轴向间隙并没有改变压气机的失速模式,但却引起失速先兆诱因的改变,表现为动叶径向流上升到叶顶后向上游波动,产生叶顶二次涡推动泄漏流溢出前缘,但大轴间隙叶顶二次涡以动叶角区径向流为主导,小轴间隙则以上游泄漏涡破碎为主导。

The numerical simulation of the 1.5-stage compressor model was conducted to study the influence of the axial distance between the guide vane and the rotating vane on the radial flow of the rotating vane. The effect of the radial flow of the rotor on the stall process was analyzed. The calculation of the axial clearance between the guide vanes and the rotating vane shows that the radial flow in the angular area gradually toward to the tip of the blade as the flow- rate decreases. When the flow is fixed, the radial flow of the rotating vane with a small axial clearance rises more. Its radial fluctuations at different heights over time are also stronger. The guide vane or rotating vane axial clearance does not change the stall mode of the compressor, but it changes the stall inception inducement which shows the radial flow of the rotating vane rising up to the top of the blade and back upstream, resulting in a secondary vortex driven leakage at the tip of the blade. The flow overflows the front edge, but the secondary vortex in the large-axis clearance blade tip is generated by the radial flow- in the angular region of the rotating blade, and the small-axis clearance is generated by the crushing of the upstream leakage vortex.