吸附式压气机叶栅端壁流场油流实验研究及数值分析

Oil Flow Visualization and Numerical Calculation on End-Wall of Aspirated Compressor Cascade

关键词:  油流显示  吸附式压气机叶栅  端壁流场  全通道计算  马蹄涡

Key words:  Oil flow visualization  Aspirated compressor cascade  End-wall flow field  Full passage simulation  Horseshoe vortex

摘要:

设计加工了压气机叶栅端壁试验件，安置在吸附式叶栅中间通道50%叶展处，用来研究无马蹄涡影响的端壁流场。通过油流显示方法得到了其在设计点4种抽吸流量下的近壁面流线分布。在抽吸缝所在相对弦长处，沿节距方向等距测取了8个试验件壁面静压值。应用Fine/Turbo软件包，采用全通道网格在设计点进行了数值计算，对试验件端壁流场进行补充分析，较好地解释了实验现象。研究发现，吸附式压气机原始叶栅端壁处的马蹄涡压力面分支未与叶型吸力面交汇，因此消除马蹄涡影响的近端壁油流试验件叶型表面负荷水平的提升主要来自于前段弦长范围内，在前40%轴向范围内叶型负荷平均提高了15.5%，并且叶型负荷随着抽吸流量的增加而增加，抽吸效率随着抽吸流量的增加而降低。在数值计算中，通过前缘处近壁面熵分布等值线最小值连线证实了油流实验中测得的角度θ客观上反映了前缘扰动区的作用范围。

Abstract:

A compressor cascade end-wall was set in middle span of the middle passage to study the end-wall flow field without horseshoe vortex effect. Structures of end-wall flow field with 4 kinds of suction rate at design point were displayed by oil flow visualization method. Eight equidistant static pressure holes along the pitchwise at the suction hole chordwise were tested. Fine/Turbo software was used in the full-passage numerical simulation in supplementary analysis. Investigations show that in original cascade end-wall，the pressure branch of horseshoe vortex passes through the passage having no effect on suction surface. So, the removal of horseshoe vortex on end-wall mainly improves the blade loading near leading edge. There is an improvement of 15.5% on blade loading in the first 40% axial position near the end-wall. As the suction flow increasing，the blade loading improves and efficiency of suction rate decreases. Minimum connection in the entropy distribution contour near the leading edge in the numerical calculation proves that the angle of θ measured in the oil visualization reflects the turbulent zone caused by the leading edge.