进气畸变下压气机过失速三维非定常模型探索

针对原压气机稳定性三维分析模型CSAC(compressor stability analysis code)加以改进,添加了轴对称左支特性。采用改进的CSAC+模型分析了NASA Rotor37在周向总压进气畸变下的稳态性能和失速起始特性,并与软件NUMECA模拟结果进行了对比,两者模拟的特性趋势一致,畸变进气下CSAC+近失速点压比与NUMECA的误差为1.05%。针对近失速点流场分析发现:随着流量的减小,在畸变区边缘的转子叶尖首先出现低速甚至逆流区,可认为该区域为失速起始位置。利用CSAC+模拟了该压气机过失速状态下的主要流动特征,分析得出进气畸变下该失速先兆为模态波,完全发展后为部分叶高失速,失速团占据约40%叶高,其传播频率约为转子转动频率的60%,并在传播过程中显示出周期性的剥离和融合过程。 

Exploration of three-dimensional unsteady model for compressor post-stall under inlet distortion

The improved three-dimensional model called compressor stability analysis code plus (CSAC+) was developed by adding an axisymmetric left characteristic. The steady aerodynamic performances and stall inception characteristics of NASA Rotor 37 under total pressure distortion inlet condition were modeled and analyzed by CSAC+. And compared with NUMECA simulation results, both of the modeling characteristics were fitted well. The relative error of total pressure ratio near stall point for both CSAC+ and NUMECA results was 1.05%. For near stall flow field analysis, it was found that as the flow rate decreased, a low speed or even reverse flow region appeared at the tip of rotor which was located behind the edge of the distortion zone. The region could be considered as the stall inception position under total pressure distortion. The stall inception and the post-stall flow characteristics of the compressor under inlet distortion were also analyzed with CSAC+. At the stall inception, the modal wave turned into part blade height stall after full development. The stall occupied 40% blade height, and the propagation frequency of the stall group was about 60% of the rotor rotation frequency. The stall group showed periodic exfoliation and fusion during propagation.