Abstract: Using a staged combustion cycle LOx/kerosene engine as an example，the engine shutdown characteristics were investigated. Based on an analysis of the system working principle of the engine，a mathematical model of the engine’s major components was established by means of the modular modeling method. An extensible simulation library for the staged combustion cycle LOx/kerosene rocket engine has been developed by using a new object-oriented simulation language-Modelica and a modeling and simulation tool，named MWorks. Furthermore，the engine’s shutdown process was simulated using the library. Simulation results agree well with the ground-test data，the relative errors of steady-state are less than 5%，and the dynamic simulation errors are less than 15%，which indicates that the model can accurately predict the shutdown behavior of the engine. Besides，some related factor for the shutdown process were considered，such as injection gas pressure，volume of fuel valve downstream chamber，and different operation conditions，whose influences were further discussed.

Key words: Liquid propellant rocket engine；Staged combustion cycle；Shutdown process；Numerical simulation

摘要： 以补燃循环液氧煤油发动机系统为研究对象，对其关机特性进行了研究。在分析发动机系统工作原理的基础上，应用模块化建模的思想，建立了该系统中各主要部件的数学模型；采用新的面向对象仿真语言Modelica和MWorks平台，开发了可扩展的发动机仿真模型库；在此基础上，利用模型库搭建了液氧煤油补燃循环发动机关机过程仿真模型，并对发动机关机过程进行了仿真计算，计算结果表明与试车数据基本相符，其中稳态相对误差小于5%，动态相对误差小于15%，初步验证了所建仿真模型的正确性；进一步分析了吹除气体压力、阀后腔道容积、关机工况等因素对发动机关机过程的影响。

关键词: 液体火箭发动机；补燃循环；关机过程；数值仿真