轴流压气机带冠静叶和不带冠静叶的比较研究

Comparison investigation of axial flow compressors with and without shrouded stators

在设计清华大学1.5级轴流跨音压气机试验台过程中,将静叶形式由带冠改为不带冠。为考察不带冠静叶能否满足气动设计要求,该文采用计算流体力学方法,对上述2种静叶形式的压气机进行数值模拟和比较分析,并对不带冠静叶间隙大小对压气机性能的影响进行研究。结果表明:不带冠静叶在设计点效率提高1.8%,且数值失速裕度提高1.5%,能够满足气动设计指标。设计点效率提高的原因在于:泄漏流和端壁二次流起到相互抑制的作用,二次流引起的分离区尺度因而得以削减。分析同时表明:在较大间隙(0.8mm)时,泄漏流会起主导作用,影响静叶根部损失和落后角分布,因此试验台加工制造中需要对静叶间隙大小进行控制。

The stator design was changed from shrouded to unshrouded for the Tsinghua 1.5-stage transonic axial flow compressor test rig to study whether the unshrouded stator met the design requirements.Both shrouded and unshrouded configurations were simulated using CFD,with the influence of the stator gap size also investigated.The results show that the efficiency is 1.8%higher at the design point and the stall margin increases by 1.5%for the compressor with the unshrouded stator.The leakage flow and endwall secondary flow are balanced at a smaller gap,but the clearance flow tends to be dominant near the endwall at a larger gap,e.g.0.8mm.Therefore,the gap size should strictly be controlled in the manufacturing process.