Modeling And Simulation Of Aeroengine Lubrication System Design

Lubrication system is an important auxiliary system for aero-engines.Its function is to continuously deliver a large amount of cleaning oil to the engine bearing and transmission gear mesh that lubricate it to reduce the friction,wear of the parts and pass away the heat generated by friction thus ensures the safety of the engine.At present,the research of lubrication system mainly focuses on the performance test of functional components,the flow resistance analysis of subsystems,the overall performance analysis of lubrication system,and the design of a certain type of engine lubrication system(manual calculation),rarely modeling and simulation studies for the system design process.Traditional manual design calculations are not only complicated and cumbersome,but also the reliability of design results is not high;however,the simulation platform designed of the lubrication system can improve design efficiency,enhance design reliability,and shorten the pre-research cycle.Therefore,it is necessary to clarify the design process of the lubrication system and establish the corresponding simulation platform.In order to model and simulate the lubrication system design process,based on the composition and working principle of different types of lubrication systems,the design flow of the lubrication system is proposed,and the design rules and design basis are given.According the design process of the lubrication system,the calculation method for the key problems in the process is determined.According to the logical relationship of the design content combined with the calculation method of the key problems,the model of the lubrication system design flow is established,including the general scheme design model,the oil supply subsystem design model,the oil return subsystem design model,Ventilation subsystem design model,thermal equilibrium analysis model,high-altitude analysis model,and functional component calibration model.According to the established lubrication system design model,the model is coded in the Visual Studio integrated environment using C++ language,and the visualization platform is realized by combining QT Designer to complete the development of the lubrication system design simulation platform.Based on the simulation platform,the lubrication system of a certain engine was designed.The comparison with the original system verified the accuracy and reliability of the simulation platform.Based on the developed simulation platform,the specific problems in the design of the lubrication system were studied.First,the effect of temperature on bearing heat generation and required oil supply is studied.The results show that changing the oil supply temperature,the heat generation of the bearing does not change much,and the amount of oil required depends on the temperature of the oil return.At the same oil supply temperature,the lower the desired oil return temperature,the greater the amount of oil required,and the increase in oil quantity is also very obvious.However,the increase in the amount of oil does not significantly reduce the return temperature,which means that it is not advisable to increase the oil flow to lower the return temperature.Secondly,the high altitude problem is studied.The results show reducing the resistance before the oil pump and increasing the residual pressure of tank can improve the high-altitude performance of the lubrication system.Finally,the effects of different blade parameters on the performance of the ventilator are studied.The results show as the number of blades,the inner and outer diameter increase,the separation efficiency changes different.Changing the number of blades,inner diameter and outer diameter has little effect on the ventilation resistance.