压气机间隙流与处理机匣作用的三维数值分析

利用Numeca CFD对某一压气机静子叶栅的间隙流动进行流场计算,并将其与具有圆弧斜槽处理结构的间隙及流场计算结果进行对比、分析.详细揭示了叶栅顶部间隙区及处理槽内的流动特征.结果表明,通过采用机匣处理,改变了压气机气流流路,形成叶尖漏流的通道,减少漏流下洗对叶片通道造成的阻塞.叶尖附近主流在叶盆尾缘气流高压作用下进入斜槽,而后气流在叶背前缘以高速由斜槽射入主流,该高速射流有效地扫除叶尖易失速的附面层,从而延迟气流分离,扩大压气机的失速裕度并减少二次流损失.这种籍助于动量交换而形成高速射流对主流的作用可能是机匣开槽结构改善失速裕度的主要原因. 

3D numerical analysis for the effect between tip clearance and casing treatment in turbomachinery

The field in tip clearance of some compressor stator was simulated by Numeca CFD, as well the field in casing treatment slots. The results were compared and analyzed, the computation showed detail streamline in tip clearance and slots. By the casing treatment, the flow path was changed, the tip leakage eddy can be passed through, so the blockage of low incline streamline can be moderated. The field near the tip enterd into the inclined slots by the high pressure from the tailing pressure side, then jet into field near the leading suction side. The jet fluid sweeped off the stalled flow, so the flow separated was postponed, and the stable operating flow range was increased, and the quadratic flow loss was decreased. The high jet effect on main flow from momentum exchange may be primary reason that slot casing improved the stable operating range.