Simulation Of Temperature Of Aviation Engine Fuel System Based On Flowmaster Software

Nowadays,as the growing demand of aircraft in supersonic cruise,stealth,mobility andother aspects,resulting in internal heat load can't be efficiently cooled.The aircraft energy integrated management can solve these problems,the core of the technology is fuel system thermal management.In high altitude and supersonic fly state,ram air is replaced by fuel,fuel becomes the primary heat sink to cool the heat load of aircraft and engine.Finally,fuel enters the combustion chamber and burns.The aeroengine is the heart of the aircraft,the high temperature fuel is harmful to safety of engine when it enter the engine.So the temperature research of engine fuel system is very significant.At present the design of aircraft and engine is separate,researchers at home and abroad all focus on the aircraft fuel system thermal management,there is little research in the field of engine fuel system thermal management.In this paper,temperature simulation calculation model and control scheme of aeroengine turbofan fuel system are studied.The main researches of paper are as follows:(1)Paper comes up with engine fuel thermal management scheme.Mainly generated heat components are analyzed: due to efficiency loss,fuel is heated when fuel fluid across the radial pump;throttling loss is transformed into heat when fuel fluid across pressure loss components.Then we in details introduce calculated method process of generated heat and oil system heat load.For research object,put forward to a thermal management scheme: we return fuel from engine to aircraft after the fuel/oil heat exchanger.(2)The temperature simulation of engine fuel thermal management is carried out.In this paper,the model of the fuel thermal management system is established by the Flowmaster software.And principles of model parts are introduced in details.Experiment and simulation temperature results are compared to verify the accuracy,results show that the performance curve of components lead to the calculation error.Temperature of all points are calculated in system.The maximum temperature is in the front of main combustion chamber,up to 155?,which seriously affect the safety of engine.The measure of taking fuel returning to the aircraft is useful.The temperature can not immediately achieve steady state when the mass flow is instantly changed under constant speeds.Finally,under variable speeds and the centrifugal pump efficiency under different working conditions is equal,exploring the relationship of fuel temperature and main combustion chamber fuel mass flow.With the rise of mass flow,thetemperature decline when the returning mass flow is 0kg/s.The mass flow rate achieve steady,the fuel temperature also is steady state.(3)For above variable speeds working conditions,paper put forward to the temperature control scheme.Closed control system contained PID controller and control system model are established by Flowmaster software.The system identification toolbox of MATLAB is used for getting the mathematical model of control object: the relationship between step signal of returning mass flow and fuel temperature.The controller is PI and the smith predicted compensator is added for controller object.The parameter of PI controller is obtained by the root locus.At last,the control scheme is simulated in Flowmaster software.The simulation results indicates that the control model has good effect on temperature.