Numerical Simulation Of Internal Flow Field In Aluminium Fuel/Water Ramjet Engines

As one of the important components of the water ramjet, metal fuel/water ramjet is a new concept propulsion system which has the advantages of high energy, great specific impluse,adjustable thrust and environment protection.In this disertation, Aluminum powder was choosed as metal fuel and waterwas choosed as oxidant. Numerical simulation of the flow field in Aluminium metal/water ramjet engine was carried out by using eddy disssipation concept model and particle surface reaction model.First of all, the combustion of composite propellant was simulated by numerical method.The correctness of the numerical simulation method was confirmed after comparing the pressure in combustion chamber with calculated one. Then the numerical simulation of the two-dimensional flow field of the Aluminium metal/water ramjet was carried out and mixing effect of Aluminum particles and water vapor was obtained when reaction didn't occur. The distribution of pressure, velocity, temperature and component in different internal flow field when the oxidant were water droplets and water vapor respectively were analyzed. We also compared the distribution of turbulent kinetic energy, turbulent dissipation, reaction rete of the gas phase, and reactants in different positions. We got the change rule of A1203 fraction and temperature of particles. The study found that compared with the condition choosing water droplets as oxidant, the combustion chamber pressure and the temperature were higher,and the residence time of particles was shorter in water vapor operating condition. The reaction rate of gas phase increases with the increase of turbulent kinetic energy and turbulent dissipation in both conditions.The influence of different parameters on the inner flow field of the engine was analyzed by changing the diameter of Aluminium powder, the second water inlet position and the second water inflow. With smaller diameter of Aluminium particles, the temperature was lower,the residence time of the particles was shorter and the interference during the particle movement was smaller. With longer axial distance of the second inlet position, the distribution of temperature in import section of nozzle was more uneven. With the second water inflow rate increasing, the temperature of the flow field was lower and the thrust of the engine was bigger.In the last, we simulated the three-dimensional flow field of the water ramjet.We analyzed the the distribution of pressure, velocity, temperature and component in the flow field.We also compared the distribution of turbulent kinetic energy, turbulent dissipation,reaction rete of the gas phase, and reactants in different positions. Compared with the two dimensional case, the pressure and temperature are higher in three dimensional case,particle movement was more complex and residence time was longer.Numerical simulation of the flow field in Aluminium metal/water ramjet engine can be carried out by using eddy disssipation concept model and particle surface reaction model. The change rule about different diameters of gas phase and particle phase was got. It can be helpful to the experimental research.