Analysis And Experimental Study On Dynamic Characteristics Of Squeeze Film Damper

Squeeze film damper can effectively reduce the vibration amplitude of the rotor and the structure is simple and reliable.So it is widely used in the field of aerospace and high-speed turbo machinery.But its strong nonlinearity may bring bistable state,lock,nonsynchronous precession and other hazards.The cavitation in the oil film is one of the influencing factors.The dynamic characteristics of squeeze film damper was studied theoretically and experimentally considering the influence of cavitation in this paper.The main contents are as follows:1)Squeeze film damper two-phase flow simulation model with cavitation model has been established based on the theory of multiphase flow.The boundary conditions were set according to the actual working condition.According to definition of the flow parameters of oil film and related criterion,studied the oil film laminar flow,turbulent flow and two-phase flow characteristics.2)The effect of cavitation on the pressure distribution and oil film force characteristics was studied based on the simulation model.The results show that the cavitation moved with a lag.Cavitation would cause the radial stiffness coefficient increase and mutation pressure distribution.The effect of cavitation on the equivalent damping coefficient is related to the vapor pressure.3)Studied the design parameters of squeeze film damper,impact state and working environment on the characteristics of oil film force by simulation.Research shows that the journal motion eccentric rate is too high would increase the oil film force and strong nonlinear.The oil film clearance is too little and the length is too long would lead to oil film failure.Cavitation make the damping effect of squeeze film weakened in high speed the rotor.High temperature would greatly reduce the damping characteristics of oil film.The cavitation has drastic influence on the oil film force characteristics.4)The two-way incentive tester was established.The visualization experiment designed to test the cavitation observation.Measured oil film pressure characteristics and compared with simulation results to verify the simulation model is reasonable and accurate.And the floating-ring squeeze film damper was studied.The study found that the floating ring can inhibit the cavitation characteristics.Two layers oil film can improve the stability and nonlinear of oil film force.The research results of this paper have important guiding significance for proposing the standards of design and use,and improving design of squeeze film damper.