Theoretical investigation on water/metal fuel ramjet motor-thermodynamic cycle and thermodynamic calculation

For achieving high-speed requirement of underwater vehicle, a conceptual engine, which utilizes the hydroreactive characteristic of several metals under supercavitation environment, has been put forward. Especially, in order to obtain specific impulse as great as possible, a dual water injection system is taken into account. Then thermodynamic cycle model, which lead the improvement of power plant and energy system, is introduced in detail, and thermal efficiency is also analyzed. Furthermore, for investigating the performance of this kind of engine system, detailed thermodynamic calculation and analysis are achieved. Especially, regarding hydroreactive metal fuel Mg/AP/HTPB as our target fuel-rich propellant, considering its obvious deficient oxygen property and the energy property of magnesium/water reaction, theoretical calculation method is established by integrating chemical non-equilibrium with chemical equilibrium. Accordingly, low limit of primary water/fuel ratio is determined. In addition, the qualitative and quantitative relationship of performance parameters, such as theoretical specific impulse, nozzle exit temperature, characteristic velocity, etc. , versus water/fuel ratio is investigated respectively.