Research On Structure Optimization Of Trust Bearing For Fixed Slope Pad

Dynamic pressure sliding thrust bearing widely applied in the bearing system ofMarine power propulsion system. With the development of modern shipbuildingindustry, propulsion bearing system is confronting the challenge of high speed, heavyload working conditions. As the key part, the operational stability of dynamicpressure sliding thrust bearing directly influences the whole performance of powersystem. In order to improve hydrodynamic lubricating property of thrust bearing, wemade an optimization research on the structure of fixed slope pad thrust bearing inthis essay.In the previous designs of thrust bearing, the two parts are mainly beingresearched which are bearing structure selection and lubricating property calculation.For selecting bearing structure, geometric parameters are initially selected throughtrial calculation, then depending on past experience and examples to choosegeometric parameters. For calculating lubricating property, first the parameters likebearing load, temperature rise, power consumption, flow rate and others need tosatisfy boundary conditions, and confirm the effectiveness of these initial parameters.However, if the initial parameters are not the one we expected, the only way we cando is returning to the first stage to select the parameters again. As we see, this designmethod which is mainly through trial calculation has limitation and blindness, andit’s unable to identify whether this program is good and bad. Therefore in this essay,we proposed an optimization design of thrust bearing to improve the designefficiency and quality of thrust bearing simultaneously and brought obviouseconomic benefit.Firstly, based on the theory of hydrodynamic lubricating and took sector padthrust bearing as the study object, the mathematic model of lubricating propertystructure were established through the elements like oil film shape equation，Reynolds equation，energy equation, viscosity-temperature equation, hot oil carrying effect equation,flow equation and so on. At the same time boundary conditions wereconfirmed. And we also took advantage of FEM to make numerical modeling oflubricating property, and then analyzed the results.Secondly, we simplified the Reynolds. Linear second order PDE which only hasnumerical solution was simplified to differential equation which has analyticalsolution. Meanwhile we derived and defined the parameters of oil film temperaturerise and friction power consumption which are used to measure the bearingperformance. Thrust bearing optimization numerical model was established as wellwhich takes the rake ratio and length-width ratio as the design variables.At last, genetic algorithm was adopted to optimize numerical model, aconclusion was made: Through altering length-width ratio and rake ratio, frictionpower consumption was reduced14%, and oil film temperature rise reduced51%.This essay theoretically analyzed the regularity of heat flow lubricationcharacteristics of thrust bearing and proposed that reasonable structure of bearingbush can improve the lubricity and load-carrying capacity. This research result has acertain engineering reference value for Dynamic pressure sliding thrust bearing.