Numerical Simulation Of Cavitation Field And Dynamic Characteristics Of Squeeze Film Damper

Gas turbine has a very broad prospects with its start and accelerate fast,power density and other advantages in the application of the ship.The rotor-bearing system is the core component of the gas turbine,and its vibration problem is related to the safety and reliability of the gas turbine machine.Squeeze film damper as a passive vibration of the original has a simple structure,vibration effect is obvious,has been widely used in the aeroengine and ship gas turbine.The formation and collapse of the bubble in the liquid oil film has a great influence on the dynamic characteristics of the extruded oil film damper because of its cavitation phenomenon in the process of oil film flow field.This paper is based on the two-phase flow theory,carried out a numerical simulation study for a type of gas turbine actual structure of the squeeze film damper.The main work is as follows:Firstly,based on the single-phase flow and two-phase flow model,the three-dimensional unsteady solution model of the extruded oil film damper is established by using the dynamic grid technique.Compared with the single-phase flow theory,the low pressure area becomes smaller and the rear portion increases when use the two-phase flow model.When the pressure value is reduced to the cavitation pressure,the oil evaporates and accumulates to form bubbles.The cavitation distribution area moves with the journal advancement,and has good periodicity.The amplitude of the volume gas is affected by the high pressure at inlet hole.Then,from four aspects,such as the precession frequency,eccentricity,oil pressure and the structure parameters of the central groove,by which analysis of oil film pressure and cavitation distribution,volume gas content and oil film force and other characteristics of the flow field characteristics affected.Further research on the dynamic characteristic coefficient identification method of squeeze film damper.On the basis of this,comparing the single-phase flow theory with the two-phase flow theory to obtain the squeeze film damper dynamic characteristic coefficient at last,the dynamic characteristic coefficients of different influencing factors are obtained at the same time.It is found that the dynamic characteristics of the extruded oil film damper are significantly affected by the precession frequency and eccentricity,and the sensitivity to the inlet pressure and the center groove parameters is relatively low.