Numerical Simulation And Experimental Research On Non-coaxial AI/AP Powder Engine

Al/AP powder engine,which employs micro aluminum(Al)powder as fuel and ammonium perchlorate(AP)powder as oxidant,is a kind of high energy propulsion equipment,which has the advantage of adjustable thrust and simple construction.It has a wide application prospect in civil and military fields.In this thesis,a numerical and experimental study on the non-coaxial powder engine is conducted.The powder injection process,flow field in the combustion chamber and particle combustion characteristics in the Al/AP powder engine with different combustion chamber configurations are investigated.The main content is as follows:(1)The mixing process of non-coaxial injection of particles in combustion chambers was numerically simulated.The particle distribution in the combustion chamber was obtained.The particle phase distribution characteristics in different combustion chambers and the flow characteristics of aluminum particles with different diameters entering combustion chamber were studied.The results show that the fluidity of particles and the radial diffusion can improve with the decrease of the diameter of the particles.The residence time of powders at downstream of combustion chamber is prolonged after installing the diaphragm figure,which is mainly caused by the entrainment effect of the reverse flow in the region between diaphragm plates.The fluidization and distribution of powder will be better after installing flame holder in the combustion chamber.The Al powder will mix with AP powder downstream and flow in a spiral.(2)The effects of different diameter of particles,mass flow rate of fluidization gas,particle mass flow ratio and configuration of combustion chamber on temperature distribution,combustion efficiency of particles,species distribution and evaporation position of aluminum particles are studied by three-dimension numerical simulation of combustion process in the non-coaxial Al/AP powder engine.The results show that the initial position of the evaporation and combustion region of particles will move toward the head of combustion chamber with the decrease of diameter of aluminum particle.Excellent fluidity of smaller particles make contribution to the radial diffusion of aluminum particles,which make the aluminum burn sufficiently.With increasing mass flow rate of fluidization gas,the peak value of temperature and the gas velocity at the outlet will also increase.However,the radial diffusion of powder fuel and other components will decrease and the reaction zone will transfer to the middle of the combustion chamber during the working process.After installing diagphragm plate orflame holder in the combustion chamber of normal configuration,the combustion efficiency of particles will go up in the case of low mass flow ratio(?): Installing diaphragm plates improves the combustion efficiency of particles significantly when the value of ? in a low level.In contrast to the former,installing flame holder in combustion chamber is the best choice when the ? is high,which makes great contribution to the improvement of particle combustion efficiency.When ? in the range of 2 to 5,the thrust will be increased by 15 to40 percent after installing diaphragm or flame holder.(3)An experimental platform of Al/AP non-coaxial powder engine is built.Powder injection process and ignition test are carried out,which found that the powder supply equipment realizes the continuous fuel or oxidant injection and the pressure change at 120 mm away from the end of the combustion chamber.The correctness of model and result is verified by comparison between the experimental pressure value and numerical results.