Numerical Simulation On Flow And Heat Transfer Of Han-based Monopropellant Rocket Engine

As a branch of a liquid rocket engine,monopropellant liquid rocket engine is widely used in spacecraft attitude control owing to its advantages of smaller size,flexibility and high precision.In recent years,with the development of aerospace science and technology,an increasing number of countries and researches are concentrating on the hydroxyl ammonium nitrate(HAN)-based monopropellant,which is a promising green monopropellant and deemed as a replacement of traditional hydrazine propellant.In this paper,the research on HAN-based monopropellant liquid engine is carried out.First of all,a simplified model is proposed to simulate the working process of hydroxyl ammonium nitrate-based monopropellant rocket engines.This simulation model is based on porous media theory,VOF(Volume of Fluid)method and the catalyst titration experiment.The model simplifies the catalytic decomposition process of liquid propellant into two separeted steps,namely one mass transfer process from liquid to cold gas and one energy release process.The mass transfer process is described using catalytic and thermal decompositions and the energy release process is described using an eddy dissipation reaction with a one-step global mechanism.Secondly,using the simulation model proposed in this paper,a one-dimensional unsteady start-up process of the HAN-based monopropellant engine is simulated using the CFD method,which makes up for the disadvantages of software Fluent in unstead flow calculation.Through the calculation,the temperature and pressure curves of the catalytic bed during engine start-up process are obtained,the pressure drop is predicted,the effects of mass flow rate and porosity is considered,all of which can used in guiding the simulation and design of monopropellant thruster.Finally,the steady-state process of a 150 N hydroxylamine-based monopropellant engine is calculated by using CFD software Fluent which turns out to be not only an engineering application but a verifition of the simplified simulation model proposed in this paper.By establishing a three-dimensional model,dividing the discrete mesh,and selecting the appropriate solver to calculate,the internal temperature and pressure parameters of the engine are obtained.The results shows good agreement with the hot test data,which prove the correctness and applicability of the proposed numerical simulation model for the new single component engine.