| The structure of the aero engine and the type of load are complex.With the development of engineering technology,the working speed of aero engine is more and more high,the rotor system often needs to work approaching and over the critical speed,which may cause a violent vibration.This is undoubtedly a higher requirement for the structural strength,stability and vibration control of the engine.Therefore,it is significant to optimize the supporting structure and improve the dynamic characteristics of the rotor system for vibration control of the rotor system.Squeeze film damper is a kind of passive control method widely used in aero engine.However,when the rotor vibration is large,the nonlinear oil film pressure will increase accordingly,which will cause complex response of rotor system dynamics.The Russian scholars put forward elastic ring squeeze film damper to control the vibration of rotor,which can improve the nonlinear behavior of traditional squeeze film damper effectively,Due to the complex motion of the oil film in the damper,it is difficult to establish the accurate oil film force model by mathematical equations.The classical lubrication theory assumes that the fluid inertia of thin oil film can be neglected.However,many studies show that the simplified classical lubrication theory without fluid inertia is too simple to reflect the real vibration characteristics of squeeze film damper.Based on the extended Reynolds equation with fluid inertia,this paper established a model of elastic ring squeeze film damper-rotor system,which is used to analyze the dynamic characteristics of the system through theoretical and numerical methods.The main contents are about:1.based on the continuity equation and Navier-Stokes equations of incompressible fluid,considering fluid inertia effects,proposed a new extended Reynolds equation.Then solved it with the finite difference method.2.According to extended Reynolds equation,analyse the influence of fluid inertia on the elastic ring squeeze film damper dynamics,and discuss the effects of eccentricity ratio,Reynolds number on fluid inertia.3.Establish the model of elastic ring squeeze film damper-rotor system,analyse the amplitude frequency response curve,the response of the resonance region and the system response with different unbalance quantities to study the influence of fluid inertia on the dynamic characteristics of the rotor system.4.Analyse the influence of elastic ring squeeze film damper designing parameters,like oil cavity,the number of elastic ring lug and shaft length of damper,on the damper characteristics and the dynamic characteristics of the rotor system. |
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