氦气透平压气机组合弹性环密封试验研究

氦气透平压气机采用间冷回热方式的闭式循环,因此高低压压气机以及涡轮进排气口处的密封与外层压力壳间就形成了不同压力的腔室,针对其各不同温度和压力的腔室采用组合弹性环密封.为验证组合弹性环的密封效果,设计了密封试验器和与机组上的组合弹性环完全一致的密封试验件,并在密封试验台上分别采用氦气工质和空气工质进行了试验对比.试验结果表明,组合弹性环具有良好的密封效果,在低压压气机出口进口、高压压气机出口进口以及高压压气机出口涡轮出口3处密封的泄漏分别占设计流量的0.0322‰、0.1035‰、0.1282‰,与空气介质相比,当封前压力为0.6～1.0 MPa时,氦气的泄漏约为空气泄漏的2倍,当封前压力较低时(0.1～0.2 MPa),氦气与空气的泄漏比较接近.

Experimental Study of a Combined Elastic Ring Seal in a Helium Turbine Compressor

As an intercooling recuperator (ICR) closed cycle is adopted for a helium turbine compressor,a variety of chambers with different pressures are formed between the seals at the HP/LP compressor and at the turbine inlet/outlet on one side and the outer-layer pressure shell on the other.A kind of combination elastic ring seal is adopted in various chambers at different temperatures and pressures.To verify the sealing effectiveness of the combination elastic rings,a seal test rig and test pieces fully identical to the combination elastic rings used in the turbine unit were designed.Moreover,on the seal test stand,a contrast experiment was performed by using helium and air working medium respectively.The test results show that the combination elastic rings have a good sealing effectiveness.The leakage rates from the seals at three locations,namely,LP compressor outlet/inlet,HP compressor outlet/inlet and HP compressor outlet/turbine outlet,account for 0.0322‰,0.1035‰ and 0.1282‰ of the design flow rate respectively.When the pressure before the seal ranges from 0.6 to 1.0 MPa,the leakage rate of helium is about 2 times that of air as compared with the air medium.When the pressure before the seal is relatively low (0.1 to 0.2 MPa),the leakage rate of helium is comparatively close to that of air.