Numerical And Experimental Study On Dynamic Characteristics For Two Sealed Ends Squeeze Film Damper

As a passive damping element,squeeze film damper is widely used in aerogas turbine,which has the advantages of simple structure,small volume,light weight and obvious damping effect.The two sealed end damper requires less lubricant than the two open end damper and can provide more damping effect.The internal flow field of the sealed damper is more complex,and the variation of the flow field will affect the damping characteristics of the SFD.Therefore,it is necessary to explore the internal cavitation flow field,temperature field and damping characteristics of sealed damper,and then analyze the influence of different structural parameters and working conditions on its characteristics,and compare the damping characteristics of simulation and experiment.The main contents of this paper are as follows:Firstly,based on Vogel’s temperature viscosity equation and the type of lubricating oil,the temperature viscosity effect of lubricating oil is considered in the numerical simulation,and the internal heat transfer process of the damper is solved by the equivalent heat transfer coefficient and the lumped parameter method,so as to obtain the three-dimensional flow field model of the two end sealed squeeze film damper with additional heat transfer process.Secondly,combined with the vortex cavitation theory,the internal complex flow field characteristics of the two end sealed damper are analyzed.By observing the streamline diagram and the pressure cloud distribution of the corresponding position,it can be seen that the vortex region mostly exists near the oil inlet hole,and the region may be in the low pressure region.The vortex has the effect of collecting the free gas core in the flow field,and the existence of vortex in the low pressure region will contribute to the occurrence of cavitation.The results show that the duration of low pressure at the monitoring point is longer than that at the opening.Therefore,the reason why the cavitation phenomenon of the sealed damper is stronger than that of the open damper is obvious.Then,the effects of different structural parameters and working conditions on the flow field characteristics and damping characteristics of the SFD are analyzed.The results show that the cavitation ratio and inner ring temperature decrease with the increase of central groove depth,number of oil inlet holes,oil film clearance and oil inlet pressure,and increase with the increase of precession radius and precession frequency;The oil film force and average equivalent damping increase with the increase of the number of oil holes and precession frequency,decrease with the increase of the oil film clearance and precession radius,and increase first and then decrease with the increase of the central groove depth and precession frequency.Finally,the experimental platform of squeeze film damper with two ends sealed is established to carry out the experiments under different oil inlet pressure and different precession frequency,and the average equivalent damping coefficient is used as a reference to compare the experimental and simulation results,so as to verify the accuracy of the simulation results.