Numerical Simulation Of Cavitation Flow Field And Structural Parameters Sensitivity Analysis Of Squeeze Film Damper

Squeeze film damper is widely used in the shafting of aviation and marine gas turbines or other rotating machinery.It not only has the advantages of small size and light weight,but also has simple structures and obvious vibration reduction effects.Due to the cavitation effect of lubricating oil,the precipitation of dissolved gas in the lubricating oil and the inhalation of outside air,the flow field of the squeeze film damper is in a gas-liquid two-phase flow state during operation.The change of the flow field will further affect the damping performance of the squeeze film damper.Therefore,it is necessary to find a calculation model that is most suitable for the calculation of the cavitation flow field of the squeeze film damper,and then analyze the influence of different structural parameters and operating parameters to optimize the structure of the squeeze film damper.The main research contents of this article are as follows:Firstly,based on the three cavitation models Singhal model,Zwart-Gerber-Belamri model and Schnerr-Sauer model built in the commercial software Fluent,the numerical simulation of the squeeze film damper was carried out respectively.The flow field characteristics and damping characteristics are compared with the experimental data.It is found that the calculation results of the Schnerr-Sauer model are most consistent with the experimental data.Therefore,the Schnerr-Sauer cavitation model is used for subsequent calculations.Then,the effects of different operating parameters on the cavitation flow field characteristics and damping characteristics of the squeeze film damper were analyzed.It is found that as the precession radius,precession frequency and lubricating oil viscosity increase,it will make the oil film pressure in the high pressure area increases,the volume fraction of gas in the low pressure area increases,and the oil film force on the inner ring increases;the average equivalent damping coefficient increases with the increase of precession radius and lubricating oil viscosity,and the effect of lubricating oil viscosity is the most significant.It will decrease with the increase of precession frequency.Increasing the inlet pressure within a certain range has little effect on the cavitation flow field and damping characteristics of this type of squeeze film damper,with no significant effect.Finally,based on the orthogonal test,the orthogonal table of the three factors of central groove depth,central groove width and oil inlet hole diameter is established,and the numerical calculation of the flow field of the squeeze oil film damper under different structures is carried out.The research shows that the extreme value of the central groove is much larger than that of the oil inlet hole,and the extreme value of the groove depth is larger than the groove width;the effect value of the center groove is continuously decreasing with the increase of the level,and the decline of the groove depth is greater than the groove width,the effect value of the inlet hole increases slightly with the increase of the level;based on the F-distribution comparison,the inlet hole diameter is determined as an insignificant factor,the central groove is a significant factor,and the depth of the groove is more significant than the groove width;finally the root mean square of the error is calculated and obtained the 95%confidence interval of the optimal predicted value of the equivalent damping coefficient is obtained.