Research On The Optimization Design And System Dynamic Performance Of Liquid Apogee Engine

The 490 N engine is used as apogee engine in all the Chinese GEO satellites.With the capcility and lifetime increase of the new generation satellite,the requirement of higer specific impulse and reliability is brought forward.This paper is about the optimization design of the second generation 490 N apogee engine.It has accomplished the optimatical design of the engine structure based on the simulation about the working process aiming at the high temperature and the uneven distribution in manufacture process of the engine,then researched the dynamic properties of the engine including the pressure-relief valve characteristics analysis,pipe filling and shutdown characteristics and engine response time aiming at the application of the 490 N apogee engine in the high-orbit satellite propulsion system.The research gives the reference on the design and system application of high-performance apogee engine.Firstly,the atomization and combustion of the engine is researched with the discrete phase model based on Euler-Lagrange method,the influence of the propellent mix ratio,central spray field,boundary cooling,and characteristic length of combustion chamber on engine performance,especially the temperature characteristics is analyzed,and the influence of manifold and pores structure on fuel distribution is analyzed by flow simulation used the practicable k-? model.The engine head and combustion chamber optimization design is then carried out based on the performance simulation.As for the engine head optimization,the keypoints are the central zone,the boundry zone and the internal flow channel designe.For the combustion chamber optimization,the keypoints are the length of cylinder part and the anti-oxidation coate design.With the new design engine,the qualifification test is carried out on 42 km hot fire test stand.The test result shows that the specific impulse of the second generation 490 N engine is 315 s with the maximum temperature less than 1400?,the temperature divergence in the weld is less than 20? and the lifetime is more than 25000 s.The effect of propellant temperature on the engine performance is also studied by ground hot fire test,a new physical model is set up for the mechanism analysis.Finally,the mathematical model,including gas tanks,gas pipes,liquid pipes,liquid pipe fillers,throttle devices,electromagnetic valves,thrustor head filling pipes,and the thrust chamber based on the apogee engine applying in the propulsion system is built.Modules of the components are set up by Modelica language and then assembled accordomg to the real propulsion system of the high orbit satelltie.The dynamic characteristics of the engine and system during start-up,steady state and shut down are numerical simulated and verified by cool flow test,the result shows the numerical method is reasonable,the analyse is valuable for the propulsion system design.