Fluid Solid Thermal Multiphysics Coupling Analysis And Fatigue Life Prediction Of Magnetic Liquid Double Suspension Bearing

Magneto-Hydraulic Double Suspension Bearing(MLDSB)is a new type of precision non-contact bearing,which combines the theory of electromagnetic levitation and hydrostatic bearing.It has the advantages of strong anti-interference ability and large bearing capacity,and can be applied to medium-speed and heavy-load occasions.Because of the two sets of magneto-hydraulic support systems of MLDSB,its structure is more complicated,and there is a phenomenon of fluid-solid-thermal coupling.The temperature of the electromagnetic coil and the magnetic pole coating increases,the thermal stress increases,the insulation material of the coil will age,and the coating in contact with the coil will crack,which will affect the running reliability of the bearing and reduce the service life.Therefore,this paper studies the temperature rise and thermal deformation of coil and magnetic pole coating under the coupling effect of fluid-solid-thermal multi-physical fields,explores the flow field and its static distribution law,predicts and analyzes the fatigue life,and provides theoretical reference for bearing structure design.The main research contents of this paper are as follows:(1)A coupled mathematical model of electro-thermal-fluid multi-physical fields of radial support unit is established to calculate the coil power and eddy current loss of the magnetic conductive sleeve;Based on the finite element analysis theory,the coupling characteristics of electro-thermal-fluid physical field of radial bearing unit are numerically simulated,the distribution law of temperature field and flow field of key parts such as coil and coating is revealed,the temperature data and flow field data of key parts such as coil and magnetic pole coating are extracted,and the influencing factors of temperature rise and thermal deformation of coil and coating are quantitatively analyzed.(2)The coupled mathematical model of fluid-solid-thermal multi-physical fields of radial bearing unit is established.Combined with temperature data,the static analysis of coil and coating is carried out,and the stress nephogram and strain nephogram under different current and oil pressure conditions are obtained.Analyzing the distribution law of stress and strain,and the dangerous position of coating crack is obtained.(3)Based on Miner’s linear damage accumulation rule,the numerical calculation model of coil and coating fatigue is established,and collecting the oil pressure change curve inside the bearing.The fatigue life of coils and coatings under different currents caused by cyclic thermal stress and oil pressure is simulated.(4)The temperature change curves of oil at the inlet and outlet of radial bearing unit under working condition were collected on the test bench of MLDSB.Compared with the simulation data,the correctness of theoretical simulation is effectively verified.