| The ground simulation device is used to simulate the high speed release of optical fibres from the wire tube during the launch and flight states of the vehicle.The increased release speed of the aircraft makes the spindle speed of the device higher,which causes the problems of high speed,fast temperature rise,short life and poor reliability of the spindle bearing to be solved.In view of this,this paper firstly,for the working conditions of the ground simulation device,after analysing the advantages and disadvantages of various types of bearings,an angular contact ball bearing with ceramic ball as rolling body with high temperature resistance and super strength characteristics was determined as the main shaft bearing,and oil and gas lubrication was determined as its supporting lubrication method,followed by the design of the nozzle structure.Based on the theory of bearing dynamics and computational fluid dynamics,a finite element analysis model was established to analyse the two-phase flow field and temperature field of oil-air lubrication in the ground simulation device.The oil-air lubrication system was finally built and commissioned.The following are the main research contents of this paper:(1)In order to simulate the distribution of gas-liquid two-phase flow in the spindle bearing cavity of the ground simulator,this paper analyses and calculates the motion state of the ball and cage in the angular contact ball bearing based on the basic equations of the multiple coordinate system method,establishes the solid domain and fluid domain models of the bearing and their corresponding mesh models,determines the VOF model,turbulence model and slip mesh model as the solution models,analyses the bearing loading The boundary conditions and the setting of the solution method are analysed;the two-phase flow field distribution in the bearing cavity is calculated by means of numerical calculation,and the influence of the oil supply volume,air supply pressure and rotational speed on the lubricant distribution is analysed.(2)The temperature of a bearing is an important indicator of its operating condition.This paper takes H7009 Cy angular contact ball bearing as an example,through the analysis of heat generation and heat transfer mode under the condition of oil and gas lubrication of the bearing,the load of the inner and outer rings of the bearing,the spin angular velocity of the ball,the heat generation rate and convective heat transfer coefficient of the bearing are calculated,and with this as the thermal boundary condition,the temperature field distribution of the bearing cavity is calculated by the method of numerical calculation,and the influence of the oil supply quantity,air supply pressure and rotational speed on the temperature field of the bearing cavity is analysed.The effect of oil supply,air supply pressure and rotational speed on the temperature field of the bearing cavity was also analysed.(3)As the viscosity of the lubricating oil changes with temperature,this paper explores the effect of the viscosity-temperature effect on the distribution of the lubricating oil and the temperature field distribution in the bearing cavity,taking into account the effect of temperature on the viscosity of the lubricating oil.The temperature of the inner and outer raceways and the ball of the bearing were found to be higher than that under the condition of constant lubricant viscosity,and the outer raceway temperature was the lowest and the ball temperature was the highest among the three. |
