Structure Design And Lubricating Performance Analysis Of Hydrostatic Bearing For Marine Propeller

Water-lubricated bearings have the advantages of environmental protection,energy saving,low cost and sustainable development.It can be used in some special occasions such as marine equipment.This paper takes water-lubricated hydrostatic bearings in marine propeller structure as the research object,designs the hydrostatic bearing structure,and analyzes the bearing characteristics of the water film under different working conditions and bearing parameters and optimizes the bearing structural parameters based on the CFD analysis software FLUENT The influence of cavitation effect on the bearing capacity of the water film is studied.Finally,the lubricating characteristics of the bearing structure of different lining materials under the action of the water film force are analyzed.The research content of the thesis is as follows:First,the working principle of the water-lubricated hydrostatic bearing and related lubrication theory are expounded,and the flow state of the water film at the bearing gap is calculated and analyzed.Based on ANSYS ICEM,the structural parameter design of the hydrostatic bearing in the ship’s ring thrust structure is discussed in detail,and the meshing method of the water film at the bearing gap and the setting of the FLUENT simulation solution process are laid,which lays the foundation for further solving the bearing characteristics of the water film.Secondly,through simulation to find out the influence of different working conditions and structural parameters on the bearing performance of the bearing water film.The effects of different eccentricity,radius gap,water supply pressure,and spindle speed on the water film pressure distribution and bearing capacity are analyzed.It is concluded that when the eccentricity,water supply pressure and spindle speed are larger and the radius clearance is smaller,the bearing capacity of the water film will increase to varying degrees,and the best bearing design clearance is By reasonably designing the shape and structure of the aqueduct and carrying out simulation solutions,it is found that the existence of the groove structure reduces the bearing capacity of the water film,but the increase in the radius of the groove has a small decrease in the bearing capacity of the water film.The final design radius is Axial circular water channel.Next,the water-film gas-liquid two-phase flow model of the hydrostatic bearing is established,the influence of cavitation effect on the bearing characteristics of the water film is analyzed,and the method of reducing the bearing effect of cavitation is proposed.After considering the cavitation effect,the overall water film pressure distribution does not change much,the main difference is that in the negative pressure area,all the pressure below the cavitation pressure becomes-97785 Pa,and the bearing capacity of the water film is slightly higher than that without considering the cavitation efficiency force.The existence of the aqueduct structure divides the cavitation area into multiple discontinuous elongated cavitation areas,which has a significant effect on reducing the occurrence of cavitation concentration.The cavitation phenomenon only occurs in the negative pressure area,and a large amount of water vapor will be generated in the cavitation area.Finally,by establishing the fluid-solid coupling model of the water film and bearing structure,the effect of the water film on the lubricating characteristics of the bearing structure of different lining materials is analyzed.It is found that the greater the elastic modulus of the material,the smaller the elastic deformation of the bearing.The elastic modulus of nitrile rubber,ultra-high molecular polyethylene and Sialon is much smaller than that of tungsten carbide,and the deformation under the action of the water film is much larger than that of tungsten carbide.Four different bearing lining materials have different mechanical properties.Among them,the deformation and maximum stress of tungsten carbide bearings are better than those of nitrile rubber,ultra-high molecular polyethylene and Sialon.