Multi-field Coupling Analysis And Lbrication Interface Modification Of Water Lubricated Rubber Bearings

Research subject derives from national defense basic scientific research project “Innovative design theories and methods of XXX based on multi-field couplings model, project from XXX institute of china ship scientific research center “Research and technology development of XXX based on mixed lubrication”, project from XXX university “Design and performance study of XXX” to study the friction, vibrating, noise, life reliability and the relative problem. A multi-field couplings model introducing asperity contact, elastic deformation, thermal deformation, bearing structure, material parameters, surface roughness, working condition, axial supply flow and other relative characteristics was proposed, to study the mixed lubrication performance of water lubricated rubber bearings. And the effects of surface hydrophilic on mixed lubrication performance was also studied, so as to evaluate the water film forming mechanism of water lubricated rubber bearings under mixed lubrication condition. The research results have a great significance on the innovative designs of water lubricated rubber bearings. The research contents are as follows:(1) It is very difficult to solve the multi-field couplings model, due to(a) the water lubricated rubber bearing is worked under mixed lubrication;(b) rubber is viscoelastic material;(c) the misalignment will be caused by the gravity of propellers. And none of the business softwares(such as ANSYS-CFD、FLUENT、ADINA) can solve that. Therefore a multi-field and multi-factor lubrication model was proposed. Besides, a new faster mixed-EHL computing technology utilizing the Odd-Even Successive Over Relaxation(OESOR) parallel numerical iterative method is proposed to minimize the execution time prolonged by the complexity caused by the multi-field and multi-factor.(2) The hydrodynamic pressure, asperity contact pressure, water film, elastic deformation, thermal deformation, friction coefficient, and maximum temperature are studied by the multi-field and multi-factor lubrication model. And the Stribeck curves with different load, velocity and misalignment are also studied to evaluate the mixed lubrication mechanism of water lubricated rubber bearings.(3) The effects of groove structure, groove shape distributions in axial direction, material parameters of rubber on the mixed lubrication performance of water lubricated rubber bearings. And a micro-wedge effect of asperities is used to illustrate the water film forming under mixed lubrication conditions. Besides, skew mesh is used to fit the spiral and herringbone groove shapes, which is more advantageous to capture the effect of the grooves more conveniently comparing to rectangular mesh. And a new approach utilizing one layer of virtual nodal points(the ghost nodes, or the imagery nodes) is suggested to treat the singularities of pressure derivatives at the turning points of a herringbone mesh.(4) A super-hydrophilic rubber surface is developed by the modification of kalium halide. The concentrations of halogenated potassium solution and modification time have significant effects on the hyfrophilic of rubber surface. And the effects of hyfrophilic of rubber surface on the mixed lubrication proformace are also studied. The results show that the water film can be formed easily on hyfrophilic rubber surface than the lyophobic case. Therefore, the hyfrophilic rubber surface can greatly improve the lubrication performance of water lubricated rubber bearings, which also transform the mixed lubrication regime into elastic hydrodynamic lubrication regime..