对转压气机叶尖间隙效应对其性能影响的研究

Research on Effects of Tip Clearance on Performance of a

关键词:  对转压气机  泄漏流  敏感度曲线  叶尖间隙  绝对涡量

Key words:  Contra-rotating compressor  Tip leakage flow  Sensitivity curve  Tip clearance  Absolute vorticity

摘要:

为了进一步了解对转压气机中不同转子叶尖间隙改变对其性能的影响，以对转压气机为对象，基于数值方法研究了该压气机不同转子对应的叶尖间隙效应及其性能的变化。结果表明:随着叶尖间隙的增加，压气机总压比和效率均有所下降；两排转子的峰值效率敏感度曲线与间隙大小均近似呈线性关系，且转子R2对应的峰值效率和喘振裕度随叶尖间隙的变化较R1更加敏感。该对转压气机存在最佳间隙组合，即转子R1和R2分别取叶尖间隙为1.0[τ]和0.5[τ]([τ]代表设计间隙)，此时的峰值效率和喘振裕度较设计间隙分别提高约0.62%和6.9%；转子叶尖间隙的增加会使得相应转子叶尖泄漏涡的起始位置后移，两排转子中一个转子叶尖间隙变化时会对另一个转子的叶尖流动产生影响，且转子R2叶尖间隙的增加对转子R1的影响更加显著；两排转子叶尖间隙的变化均会影响该对转压气机的最先失速级。

Abstract:

In order to further understand the effects of the tip clearance variation of different rotors on the performance of a contra-rotating axial compressor (CRAC)，numerical simulations are carried out for a contra-rotating axial compressor to investigate the tip clearance sensitivities of different rotors and the performance variation of this compressor. The results show that both the compressor total pressure ratio and efficiency decrease with the increase of tip gap，and the sensitivity curve in rotor peak efficiency for both rotors is found to be approximately linear with an increase in tip clearance. Compared with rotor1，the variations of peak efficiency and stall margin are more sensitive than those of rotor2 with the increase of tip clearance. There exists an optimum tip gap combination for this CRAC，i.e. 1.0[τ] for rotor1 and 0.5[τ]for rotor2 ([τ]represents the design tip clearance)，and the peak efficiency and stall margin are improved by about 0.62% and 6.9%, respectively. The onset location of tip leakage vortex is shifted downstream when the tip gap increased. For one of the rotors in this CRAC，the tip flow is influenced by the tip gap variation of the other rotor，and rotor2 shows a more significant impact on rotor1. Additionally，the first rotating stall stage is also influenced by the tip clearance variation of both the rotors.