Research On Lubrication Performance Of Ship Journal Bearing Based On Oil-water Mixing

The ship journal bearing is one of the important components of its propulsion shafting,its main function is to support and control the circumferential movement of the shaft.For civilian ships and ships,the seawater enters the oil-lubricated journal bearing or the cooling pipe is broken,so that the cooling water is mixed into the lubricating oil to form a lubricating condition of the oil-water mixture.This extreme working condition will inevitably lead to severe wear of the journal bearing.The failure of the ship propulsion system seriously threatens the vitality or combat effectiveness of the ship.Therefore,mastering the law of lubrication performance of journal bearing under oil-water mixture working conditions can provide a theoretical basis for the evaluation of subsequent service life,so as to understand the time when the civilian ship is waiting for rescue or the ship leaves the theater.For the research on the lubrication performance of oil-water mixture,the oil film bearing on the turbine and the rolling mill is mainly concentrated,and the journal bearing of the ship is less involved.In this paper,the journal bearing is taken as the research object.Through the simulation calculation and experimental means,the influence of oil-water mixing on the heat flux lubrication performance of journal bearing is studied.The research contents and conclusions are as follows:(1)The viscosity test of the oil-water mixture was carried out and the results were analyzed.The results showed that the viscosity of the oil-water mixture decreased with the increase of temperature,and the decrease trend was similar to the exponential function.In general,the greater the viscosity of the lubricating oil,the more sensitive it is to changes in temperature.The viscosity first increases with the increase of water content,reaches a maximum when the water content is about 30%,and then decreases rapidly and gradually stabilizes.(2)According to the basic equation of hot flow pressure lubrication,the mathematical model of heat flow lubrication of oil-water mixture of journal bearing is established,and then the program is programmed by MATLAB software.The simulation results are compared with the calculation results of the reference documents,and the error is within 5%.To a certain extent,the model agrees well and gives some theoretical support for the subsequent lubrication performance simulation work.(3)Numerical analysis of the difference in distribution of liquid film pressure,thickness,temperature,bearing capacity and friction force with different water content.The results show that when the water content is less than 30%,the liquid film pressure decreases with the increase of water content,when the water content When it is more than 30%,it increases as the water content increases.The liquid film bearing capacity and frictional force increase with the increase of water content.As the water content increases,the minimum thickness of the liquid film neutral surface increases,while the liquid film temperature increases.(4)The experimental study on the lubrication performance of oil-water mixture was carried out.The lubrication performance parameters such as liquid film pressure,friction torque and lubricating oil temperature rise were measured when the water content of Babbitt alloy half-bush bearing was not more than 30%.With the increase of water content,the liquid film pressure decreases at the same measuring point.At the same speed,the friction coefficient increases with the increase of water content.With the increase of lubricating oil temperature,the friction coefficient decreases.When the test spindle rotates for the same time,the more the water content of the lubricating oil,the greater the temperature rise.