处理机匣对高压压气机性能和稳定性影响的数值模拟和试验研究

Numerical Investigation of Casing Treatments Influence on Performance and Stability of a HPC First Stage

本文主要采用数值模拟和试验验证的方法探索轴向斜槽处理机匣改善高压压气机尖部流动情况及扩大压气机稳定工作边界的基本原理。采用Numeca CFD软件对某多级高压压气机第一级叶尖间隙流场和具有轴向斜槽处理结构的流场进行非定常计算,并对计算结果进行对比、分析,详细揭示了叶栅顶部间隙区及处理槽内的流动特征。数值计算结果显示,轴向斜槽处理机匣能够衰减或是消除叶尖的泄漏涡,推迟失速的发生。处理机匣对压气机性能的影响并不是直接采用对泄漏涡的干涉,而是通过叶尖附近气流在高压作用下从压力面尾缘进入斜槽,而后气流在叶背前缘以高速由斜槽射入主流。该高速射流能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。试验结果显示,该多级压气机采用轴向斜槽处理机匣有效地减少了尖部气流泄漏,扩大了压气机稳定工作范围。

Experimental and numerical investigations were conducted to study the fundamental flow mechanisms of the axial skewed slot casing treatment of a HP compressor and the influence on compres- sor stall margin. The field in tip clearance of a research multistage compressor first stage was simulated by Numeca CFD software, as well the field in casing treatment slots. The numerical results were compared and analyzed, which detailed the flow structure in tip clearance and slots. Numerical simulations showed that configurations with axial skewed slots postponed the onset of stall. Observations indicated weakened the characteristic tip leakage vortex and that casing treatments did not interfere with the vor- tex directly. The key mechanism seemed to lie mainly in the field near the tip flow entering into the skewed slots by the high pressure from the tailing pressure side, then jetting into main flow near the leading suction side. The jet stream swept off the stalled flow, so the stall onset was postponed, and the stable operating flow range was increased, and the quadratic flow loss was decreased.