Research On The Characteristics Of The Porous Aerostatic Thrust Bearing Crossing The Slot In The Microgravity Simulation Experiments

In the field of microgravity simulation,with porous aerostatic thrust bearing as the core component,the full-physical air floatation simulation platform has the advantages of low cost,easy maintenance,unlimited simulation time,high simulation accuracy.In this paper,the static characteristics of the process of porous aerostatic thrust bearing crossing the slot in microgravity simulation experiments are researched.As a result of the existence of the slot,when the aerostatic thrust bearing cross it,the original boundary conditions of the carrier air film change and the air in the air film gap is directly connected to the atmosphere.Therefore,the pressure of the air film around the slot is rapidly unloaded and the bearing capacity of it decreases.At the same time,the distribution of the pressure of the air film is no longer symmetrical than the axis of the bearing center and the bearing will be inclined.In this paper,the static performance of the bearing crossing the slot is analyzed theoretically under two assumptions of constant air film thickness and bearing inclination.When the bearing inclination in the slot is ignored and the bearing air film thickness is considered to be uniform,the 1D flow model of porous air lubrication is solved.The influencing factors of the bearing capacity,stiffness and overturning moment of the bearing film are analyzed in detail,which include permeability of porous materials,air supply pressure and width of the slot,etc.The method to improve the static performance of the bearing crossing the slot is given.In order to solve the incline problem of the bearing in the process of crossing the slot,firstly,the inclination of porous air thrust bearing under eccentric load when not crossing the slot is studied.Finite element and genetic algorithm are used to solve the slant attitude of air bearing under eccentric load,and the relevant algorithm is verified by experiments.Then the thickness of the bearing air film and tilt angle when crossing the slot are analyzed in detail.Compared with the air film with fixed thickness,the calculation results are given.Finally,an experimental platform is built for the experimental study of dynamic and static characteristics of air thrust bearing when crossing the slot.In the process of bearing crossing the slot,the variation trend of bearing average thickness of air film and tilt angle are studied in detail.The experimental results are consistent with the theoretical analysis ones.