Study On Static Loading Characteristics Of Aerostatic Thrust Bearing Over Slit

Aerostatic bearing has been extensively utilized in many areas, such as highspeed and precision engineering, microelectronics, medical devices, space technologyand so on. This is mainly due to the reason that it has loads of merits, such as highprecision, simple structure, tiny friction and long life, etc. Especially in the aerospacefield, the air bearing spacecraft simulator is designed to simulate the various DOFmovements of the spacecraft, which can deepen the study of spacecraft. The principleof this kind of simulator is to rely on a certain pressure of air in the gas film betweenthe aerostatic thrust bearing and supporting platforms to support other devices on thesimulator. However, it is so difficult to produce the large flat and high-precisionsupporting platform that the large flat platform is made up of a multitude of littleblocks, which, as a result, makes it inevitable to generate lots of gaps on the platform.This paper will study the possible factors that have essential influence on the staticloading capacity of the aerostatic thrust bearing when it is located above the slit, andlay the foundation for the design of aerostatic bearing simulator with large flatplatform through this study.Due to the fact that slit exerts the influence on flow characteristics of the gas infilm when aerostatic bearing is located above the slit, therefore, this paper will, tostart with, analyze theoretically gas throttling types that may occur in the flowchannel, then analyze the factors that impact air bearing static characteristics,including the supply pressure, film thickness, the diameter and number of air intakeand slit structure.The6-holes ring distribution and the12-holes double ring distribution are twomain forms of aerostatic thrust bearing in engineering field, thus, this paper willestablish the relevant simulation models when these two kinds of aerostatic thrustbearing cross the slit through the FLUENT software which is based on the finitevolume method, the k-ε turbulence model will be introduced into the numericalsimulation and the ideal gas model will be utilized for studying the staticcharacteristics fo aerostatic thrust bearing when crossing the stitch. Firstly, this paperwill analyze the static bearing capacities and inlet flow rates respectively whenaerostatic thrust bearing is located in four different positions above the slit and studythe impacts of the seam positions. Then this paper will study the laws which the gasfilm thickness, air intake diameter, number of air intakes, supply pressure, the slitwidth and slit depth impact on the bearing static bearing capacity, static stiffness and the inlet flow rate when the bearing center is located above the slit, and propose themethods to improve static characteristics of the6holes air bearing crossing the stitch.Furthermore, the12-hole double ring and staggered distribution of aerostatic thrustbearing will be simulate to analyze the impacts that the two positions of aerostaticbearing center cross the slit exert on static loading capacity and inlet flow rate andcompare with the case without slit, consequently, this paper will analyze the impactsof the gas film thickness and supply pressure on the bearing static characteristics, andcome to a conclusion that the slit has less influence on the12hole double staggereddistribution aerostatic thrust bearing in comparison with the case of six holesaerostatic bearing.Finally, this paper will make the experiments to study the impacts of the supplypressure and film thickness on static loading capacity of aerostatic thrust bearingcrossing the slit and verify the accuracy of the simulation results. The results showthat the factors that impact on static charateristics of aerostatic thrust bearingcrossing the slit and the methods to improve these static charateristics, which cancontribute to the study of the aerostatic bearing move on the large flat platform withslit.