Research On Analysis Of Hydro-reactive Metal Fuel Underwater Dynamic Performance

Hydro-reactive metal fuel is widely used in the propulsion system of underwater high speed vehicle due to its high energy and high specific impulse.Metal fuel water ramjet engine has the advantages of simple structure,high reliability and green environmental protection,which is the focus of the world’s military power.In this disertation,the computational fluid dynamics software Fluent is used to simulate the working process of a hydro-reactive metal fuel ramjet engine with aluminum powder as the main fuel and atomized water droplets as the oxidant,in different fuel injection forms and different navigational conditions.First of all,the two-dimensional internal flow field of hydro-reactive metal fuel ramjet was simulated by numerical method,and the simulation results are compared with the experimental data in the literature to verify the rationality of the numerical simulation method.Afterwards,the numerical simulation of the flow field in the metal fuel water ramjet in different fuel injection forms was carried out,and the internal flow field parameters distribution of the engine under different operating conditions were compared and analyzed.The study found that change of the fuel injection form has little effect on the combustion chamber pressure and exhaust velocity of the engine;for a water jet engine with a single injection,the high temperature area in the combustion chamber is mainly located between the primary water inlet and the secondary water inlet of the combustion chamber;for a water jet engine with double injection,the high temperature area in the combustion chamber is concentrated on the front of the engine.Secondly,the three-dimensional flow field of hydro-reactive metal fuel with a Laval nozzle as a thruster was simulated by numerical method,at different voyage depths and voyage velocities.The pressure,velocity and temperature distribution of the internal flow field,and the variation of engine exhaust velocity,specific impulse,thrust coefficient and characteristic velocity under different working conditions were analyzed.The study found that the greater the depth of the underwater vehicle,the higher the temperature in the combustion chamber of the engine,the exhaust velocity,specific impulse,thrust coefficient and the characteristic velocity are reduced;the greater the speed of the underwater vehicle,the higher the chamber pressure,the lower the chamber temperature,engine exhaust velocity,specific impulse and the thrust coefficient are increased,and the characteristic velocity decreases.The depth of voyage for the metal fuel water ramjets studied here should not greater than 30 m.The research methods and results of this disertation can provide a theoretical reference for the application of water-reactive metal fuel ramjets in underwater vehicles.