周向总压畸变对对转压气机影响效应分析

Effects of Circumferential Total Pressure Distortion on Flow Field in a Contra -Rotating Axial Compressor

关键词:  对转压气机  进气畸变  临界畸变角  畸变指数  失速裕度

Key words:  Contra-rotating compressor  Inlet distortion  Critical distortion angle  Distortion coefficient  Stall margin

摘要:

以对转压气机为研究对象，在数值方法校验的基础上，应用全通道定常流场分析手段计算了对转压气机不同周向畸变条件下的三维流场，获取了周向总压进气畸变对该压气机性能以及流场结构的影响效应，确定了对转压气机的临界畸变角，分析了不同畸变强度对压气机性能的影响规律，探讨了周向总压畸变在对转压气机中的发展演化过程。结果表明:(a)所研究的对转压气机临界畸变角约为72°，略高于传统动-静叶排交替的压气机临界畸变角；(b)相比均匀进气工况，当畸变指数为0.24时，对转压气机失速点压比和失速裕度分别下降3%和9.6%，当畸变指数为0.5时二者分别下降8.3%和19.8%;(c)未畸变区与畸变区流体之间存在的压力梯度影响转子叶片相对来流速度。进入畸变区叶片来流相对速度减小，负荷降低，退出畸变区叶片来流相对速度增大，负荷增大;(d)上游转子使得畸变水平提高，下游转子反向旋转效应抑制了来流相对速度变化趋势，增强了气流在其叶片通道中的掺混，使得畸变水平有所下降。

Abstract:

This paper presents analysis of the circumferential total pressure distortion in a contra -rotating compressor(CRAC) by three dimensional steady full-passage numerical simulations，based on the validation of numerical results by experimental data. The critical distortion angle has been decided and the effects of different distortions on the performance curves and detailed flow structure have been analyzed with the focus of distortion spatial transfer in the CRAC. The results show that:(a)The critical distortion angle of the CARC is about 72°，which is a little larger than the traditional compressor(rotor and stator alternate arrangement).(b)The total pressure ratio and stall margin on the stall point have decreased by 3% and 9.6%，respectively，with distortion coefficient at 0.24 compared with uniform inlet condition. When the distortion coefficient is 0.5，the percentages are up to 8.3% and 19.8%，respectively.(c)The pressure gradient along the circumferential direction affects the relative velocity of the rotors distinctly，which plays different roles of the two counter rotating rotors. The incoming relative velocity and load of a rotor decrease when it enters into the distortion zone. On the other hand，the relative velocity and load increase when a rotor leaves the distortion zone.(d)The distortion level is amplified by the upstream rotor. The effect that the downstream reversed rotating rotor strengthens the mixing ability of flow，suppresses the development of distortion flow and then reduces the distortion level.