Numerical Simulation Model Of HAN-Based Mono-propellant Rocket Engine

The range of monopropellant liquid rockets is very wide.In the past,toxic propellants were used when a monopropellant was required in many countries.But in recent years,we have studied monopropellant to protect the environment and astronauts.In this paper,a single component engine of HNO3 based non-toxic propellant is taken as the research object,and its simulation model is established and simulated.This paper discarded the method used by other scholars to simulate the motion of liquid jet by the discrete particle model(DPM).The two fluid models was used to approximate the liquid propellant flow and gas flow in the catalytic bed,and the catalytic reaction process of the liquid phase to the gas phase was also included.In view of the phase transition process of liquid propellant,a phase transition model of first order reaction based on catalytic reaction experiment is first proposed.Then a piecewise phase transition model is proposed based on the experimental data of high temperature pyrolysis.On this basis,the flow and the heat transfer of liquid propellant in the catalytic bed of an engine is described in combination with the porous media theory.Two dimensional simulation and model parameter analysis of HAN based single component engine show that the catalytic reaction process is the main controlling step of the engine's working process.The temperature gradient of the front bed of the catalytic bed is the largest.When the pre exponential factor of the catalytic reaction is lowered,the temperature gradient of the front bed becomes smaller.The catalyst bed has the highest temperature and is basically equal to the theoretical decomposition temperature.It shows that the reaction in the back bed is mainly pyrolysis,but if only the catalytic decomposition model is used,the reaction rate can not be completely reacted to all propellants,and the theoretical pressure can not be reached,which indicates that the pyrolysis reaction is improved in the engine.Performance plays an important role.The simulation results show that the model can well simulate the flow and heat transfer in the HAN based single component engine and the simulation results are in good agreement with the test data.