Supersonic Flow Field Characteristics And Simulation Research Of Hybrid Gas Bearing With Microcavity-orifice Throttling

Dynamic and static pressure gas bearings are widely used in the field of ultra-precision machining due to their high precision,high speed,and radiation resistance.However,as the core component of ultra-precision machining machine tools,the bearing capacity is slightly lower and the supersonic flow field appears frequently.It is difficult for ultra-precision machining machine tools to be suitable for large load-bearing conditions.This paper proposes a microcavity-orifice throttling section flow static pressure gas bearing,which adopts the form of combining small hole throttling and deep and shallow cavity structure.Using the theoretical knowledge of fluid mechanics combined with simulation methods,the flow static of this microcavity-orifice throttling section is studied and analyzed.The load-bearing characteristics,supersonic flow field characteristics and dynamic characteristics of pressurized gas bearings.Provide theoretical basis and design basis for the practical application of dynamic and static pressure gas bearings in the field of ultra-precision machining.Firstly,the structural design of the microcavity-orifice throttling section mobile static pressure gas bearing spindle was carried out and the three-dimensional model of the microcavity-orifice throttling section flow static pressure gas bearing was established.The CFD method is used to study the load-bearing characteristics of the microcavity-orifice mobile static pressure gas bearing,and the pressure distribution cloud diagram of the gas film flow field of the microcavity-orifice mobile static pressure gas bearing is analyzed,and the eccentricity,air supply pressure,spindle speed,The influence of factors such as average air film thickness and shallow cavity depth ratio on bearing capacity and static stiffness.It provides a design basis for improving the load-bearing performance of the microcavity-orifice throttling section mobile static pressure gas bearing.Secondly,analyze and study the supersonic flow field of the microcavity-orifice hydrostatic gas bearing,and analyze the area where the supersonic gas flow appears in the gas film flow field of the microcavity-orifice hydrostatic gas bearing,the location of shock wave generation,and the average gas.The influence of film thickness and orifice diameter on supersonic flow field.It provides a reference for how to avoid the supersonic flow field of the microcavity-orifice throttling section flow static pressure gas bearing.Finally,the dynamic grid technology of ANSYS software is used to simulate and analyze the dynamic characteristics of the microcavity-orifice mobile static pressure gas bearing.It is revealed that the stiffness coefficients and damping coefficients of the microcavity-orifice mobile static pressure gas bearing vary with the gas supply.The change law of pressure and spindle speed,and the experimental program of the microcavity-orifice throttling section mobile static pressure gas bearing is studied.This is of great significance for the realization of high performance of the microcavity-orifice throttling section mobile static pressure gas bearing in the ultra-precision machining machine tool.