Research On The Design Of Thrust Ball Bearing For Pumps In Hydropower Station And Its Magnetic Film Lubrication Characteristics

The uncontrollability of the traditional lubricant and its lubricating elements decrement with time makes the life of the thrust bearing of the water pump hard to predict and thus becomes the hidden danger of the project,which seriously affects the production benefit of the hydropower station,and puts forward higher requirements for the lubrication life and management of the thrust bearing of the water pump.In order to reduce the friction and wear of the thrust bearing of the water pump,the magnetization and viscosity characteristics of the magnetic fluid were combined in this paper to apply it to the lubrication of the water pump bearing.The theory,simulation and experiment of the magnetic film lubrication of the thrust ball bearing of the magnetic fluid were carried out.The main results are as follows:1.According to Hertz contact theory,combined with finite element simulation analysis and numerical analysis method,the thrust ball bearing structure was optimized based on the optimized stainless steel bearing material.Based on this structure,a new magnetic thrust ball bearing and its ring raceway magnetic field control mode are innovated.2.Based on the magneto-hydrodynamic lubrication equation and the contact coupling theory of thrust ball bearing,combined with the finite element simulation analysis,the elastohydrodynamic lubrication mechanism of magneto-hydrodynamic oil film was studied in this paper.The results show that: 1)When the external magnetic field is present,the oil film thickness of the magneto-fluid is higher,and the surface contact stress of the contact area is smaller;2)With the gradual increase of external magnetic field strength,the viscosity of magneto-fluid oil film increases rapidly.When the magnetic induction intensity reaches 0.02 t,the viscosity of magneto-fluid oil film tends to saturation.3.On the basis of tribological tests of magnetic particles in dry friction and oil-lubricated environment,experimental studies on the lubrication properties of magnetic film of magneto-fluid thrust ball bearings were carried out.The results show that: 1)When there are magnetic particles in dry friction or oil-lubricated environment and there is external magnetic field(B=324Gs),the friction coefficient of the bearing is less than that without external magnetic field;2)Bearing friction coefficient and sample wear degree during magneto-fluid lubrication(B=220Gs)are less than those during turbine oil lubrication.To sum up,the magnetic fluid thrust ball bearing designed in this paper has strong bearing capacity and considerable anti-friction and anti-wear effect,which can provide theoretical and experimental basis for the lubrication life study of thrust bearing of water pump in hydropower station.In addition,the external magnetic field has obvious antifriction and control effect on bearings with magnetic particles in dry friction oroil-lubricated environment,which can provide a new idea for industrial treatment of magnetic abrasive wear of friction pair.