Study On The Influence Of The Permeability Distribution Characteristics On Porous Air Bearings’ Performance

The aerostatic bearing meets the requirements of high precision, high speed andhigh resolution of the precision processing machinery and the mechanical part ofmeasuring instruments. What’s more, for the special throttling effect of the porous airbearings, it has a greater carrying capacity than the traditional orifice compensated gasbearings and shows great development prospects. In this paper, as regards to thepermeability of porous materials the main factors that affect the performance ofporous gas bearings, theoretical and experimental research have been carried out,mainly the following tasks are completed:Through the analysis of the mechanism of the gas flow in the capillary channelof porous material, the possibility of the existence of slip flow inside the porousmaterial has been proved and a slip flow correction factor is added to the permeabilityformula. Through the fractal dimension got by Surface3D profiler and the maximumporosity of the porous materia got by the bubble method experiments, the theoreticalpermeability values are obtained, and the final results are verified by experimentaltesting.A permeability test on the porous material test block suppressed by the copperparticles is carried on. The general laws about the permeability of the porous materialsmade of different particle radius are studied, as well as the influence of differentprocess on the permeability of the porous material as well.A loading experiment on the porous gas bearings of different surface processingstates is conducted, and the influence of milling and grinding on the bearings’ capacityand stiffness has been analyzed. At the same time, through the analysis of the gas filmthickness of the six test points on the gas bearing, the presence of tilt during theworking of the gas bearings has been ascertained. Through the porous materialpartition experiment, the permeability of the porous material on the surface aftermachining uneven distribution characteristics are analyzed, thus explaining the gasbearings tilt phenomenon. The influence of the different surface machining state onthe inclination angle of the porous gas bearing is also studied.By the multifractal of the porous material in the subject, and through the establishment of the porous material’s multifractal spectrum, the nonuniformdistribution of the porous materials pore is studied.The content of this paper provides a theoretical and experimental basis for theresearch and manufacture of porous gas bearings, at the same time it lays foundationfor the study of the permeability of porous media and its distribution.