应用于高速透平膨胀机的箔片动压气体止推轴承的试验研究

摘要

For complex constructed foil bearing, it is difficult to theoretically analyze and apply to high speed rotation machinery. Three types of compliant foil bearing, including plate foil bearing, viscoelastic support foil bearing and foil bearing with convex dots, are proposed and investigated. On a test rig of high speed turbo machinery, the bearing-rotor system is driven by gas turbine, and the load capacity of foil thrust bearings is analyzed by hydrostatic gas bearing supporting and applying axial load. To discuss the running stability of foil thrust bearings, fast Fourier transform is chosen to analyze the vibration signals of bearing-rotor system. The results show that plate foil thrust bearings have the highest load capacity of 44 N, the rotor obit of bearing-rotor system gets stable. The fundamental frequency is dominated in frequency domain, and the lower and higher frequencies can be ignored.%针对现有箔片动压气体轴承结构较为复杂、理论分析比较困难,以及难以应用于高速旋转机械等问题,提出了改进的平箔型、黏弹性支承型、鼓泡型等箔片动压气体止推轴承.在高速透平机械气体轴承试验台上,采用透平驱动转子-轴承系统以及静压轴承支承活塞杆施加轴向力等试验方法,对箔片动压气体止推轴承在不同转速下的承载性能进行了试验研究.同时,利用快速傅里叶变换方法,分析轴承-转子系统在空间3个方向的振动信号,对箔片动压气体止推轴承的运转稳定性进行了探讨.试验结果表明:平箔型动压气体止推轴承具有较高的轴向承载力,约为44 N,而鼓泡型动压气体止推轴承的性能非常稳定,轴承-转子系统的轴心轨迹十分清晰,轴向振动信号中低频和高频涡动可忽略不计,其振动频率以1倍频为主.