Modeling And Simulation Of Cryogenic Liquid Rocket Engine Static Characteristics

Simulation and analysis of static characteristics is an important link and necessary means in the development of liquid rocket engine.A lot of work has been done on the simulation of the static characteristics of liquid rocket engine at home and abroad,and a series of academic achievements have been obtained,which provide the basis and guidance for engineering practice.However,compared with foreign countries,there are still large gaps in the accuracy of the model,the universality of the platform and the application research of static characteristic analysis of cryogenic rocket engine in China.For this reason,this paper carried out the modeling and simulation analysis of the static characteristics of cryogenic rocket engine,established the static characteristics model library of cryogenic rocket engine,and carried out research on the performance reliability,performance parameter sensitivity,parameter regulation characteristics,fault simulation and diagnosis of cryogenic rocket engine and other hot engineering issues.In this paper,the static characteristics of various components of cryogenic rocket engine are analyzed theoretically,and the static characteristics models of main components such as turbo pump,combustion device,pipeline and throttling element are established.In view of the fact that the density and temperature of cryogenic propellant vary greatly after the pump,a post-pump temperature rise model is introduced to improve the accuracy of calculating the lift and efficiency of the cryogenic pump.Aiming at the large error of heat transfer calculation of hydrogen-oxygen thrust chamber cooling jacket,the calculation model of cooling jacket was modified by theoretical analysis and experimental data summarization,and a heat transfer calculation model of hydrogen-oxygen thrust chamber cooling jacket with high calculation accuracy was proposed.Aiming at the problem that the cavitating venturi model based on Bernoulli equation is not suitable for liquid hydrogen,the isentropic algorithm is introduced to solve the flow calculation problem of liquid hydrogen cavitating tube.Aiming at the attention of the engine system to the structure quality characteristics,the existing engine structure quality estimation model was modified according to the actual data of cryogenic engine,and the approximate simulation model of structure quality of cryogenic engine was established.Based on the mathematical model of the static characteristics of various parts of cryogenic rocket engine and the idea of modular modeling,the simulation modules of the static characteristics of the main parts of cryogenic rocket engine are constructed using Modelica language,and on this basis,formed the model library of the static characteristics of cryogenic rocket engine,and formed a general simulation platform for static characteristics of cryogenic rocket engines.Based on the static characteristic simulation platform,the performance reliability evaluation and performance parameter sensitivity analysis of the liquid oxygen/methane engine were carried out.Through single factor sensitivity analysis and multi-factor sensitivity analysis,combined with range analysis and variance analysis,the parameters that have the greatest influence on the performance of this type of engine are obtained,and the significance of these parameters on the performance is pointed out.In this paper,the parameter regulation characteristics of the full-flow refuel cycle engine are studied.Considering the regulation precision and the working reliability of the valve,the variation characteristics of the engine component parameters when the thrust and mixing ratio are adjusted by various regulation schemes are analyzed,and the relatively better regulation schemes are compared.The static characteristic fault simulation and analysis of the 50-ton hydrogen-oxygen rocket engine were carried out,and the variation trend and degree of the key parameters of the engine under various fault modes were obtained.