Dynamic Response Analysis Of Rotor Supported On Floating Ring Squeeze Film Dampers

To prevent a series of problems caused by nonlinear stiffness and damper of traditional squeezefilm damper (TSFD), dynamic responses of a rotor supported on floating-ring squeeze film dampers(FSFD) are studied in this paper. The main work and results of this paper are briefly summarized asfollows:(1) Two dynamic models of FSFD are established. One model is based on the general Reynoldsequation, and the other model is based on the Reynolds equation of squeeze film damper. The mosterror value of system response with two different models is less than4%. To validate the two models,a non-rotating test rig excited by two orthogonally placed shakers is established. Good consistency isachieved between the experiment and simulation results with two different models. Two models arevalidated. In addition, the vibration attenuation mechanism of FSFD is studied by means ofamplitude-frequency response characteristic of single degree of freedom system. The results provideresearch foundation for further analyzing and applying FSFD.(2) Two dynamic models of a rotor supported on FSFD are established respectively with orwithout nonlinear force of ball bearings. Numerical results show that the performances of FSFD inpreventing bistable, non-synchronous and suddenly applied unbalance response are better than TSFDon the same computation conditions. The effects of parameters of FSFD, ball bearing and rotor havealso been numerically investigated in preventing bistable, non-synchronous and suddenly appliedunbalance response. According to the amplitude-frequency response of the rotor system, it shows thatthe greater mass of floating-ring and viscosity of lubrication oil, the greater is the damping property,vice versa. Comparing to TSFD, FSFD has a better performance in preventing bistable response in theexperiment.(3)Two different FSFD are studied, one has single layer film, which is named as FSFDS; and theother has double layers film, which is named as FSFDD, and each floating-ring has an elastic support.The performances of FSFDS in preventing non-synchronous and suddenly applied unbalance responseare better than TSFD; FSFDS is effective in preventing bistable response at the cost of increasedvibration at the first critical speed. The performances of FSFDS in preventing bistable,non-synchronous and suddenly applied unbalance response are worse than FSFD. The performancesof FSFDD in preventing bistable, non-synchronous and suddenly applied unbalance response arebetter than TSFD and FSFDS. But the performances of FSFDD in preventing bistable,non-synchronous and transient amplitude of suddenly applied unbalance response are worse thanFSFD. Therefore, the FSFD possesses a good prospect of engineering application.(4) Based on the models of nonlinear FSFD, TSFD and ball bearing, a dynamic model of a dualrotor supported on ball bearings with FSFD/TSFD is established, the main conclusions are brieflysummarized as follows: the clearance of intershaft bearing and support bearing have significantinfluence on the response frequency of dual rotor system. FSFD can more effectively in preventingnon-synchronous response of dual rotor system than TSFD. More frequency component will appear inthe response of dual rotor system including rubbing fault. It provided theory reference for dynamic characteristic analysis and Fault Diagnosis of FSFD/TSFD-ball bearing-dual rotor system.The research of this paper provided theoretical model and research foundation for furtherresearching FSFD and dynamic responses of a rotor supported on FSFD. It also provided theoryreference for engineering application of FSFD.