Numerical Simulation Of High Energy Fuel Combustion Flow Field

Li/SF₆ Chemistry Heat Source System was one kind of the advanced thermal power systems taken the metal liquid lithium as the fuel, and sulfur hexafluoride the oxidizer. The molten lithium was one kind of high-energy liquid-metal fuels. Reacting with sulfur hexafluoride, 1kg lithium could be produced heat at the rate of 13kW·h. The system was unique in that it had a high energy density, high specific energy, and it was unaffected by external environment, and that it yielded condensed-phase products under normal operating conditions. It was an obvious advantage whether was applied to underwater propulsion or propulsion equipments of an outer space or other special environment; therefore, it was the matter of vital practical significance to this aspect research.The basic conservation equations and the models were constructed reflecting the structure and combustion flow law in the Li/SF₆ Chemistry Heat Source System. The mathematical models of physical was built to describe an unsteady chemical reaction in the system: applying the RNG k-εtwo equations turbulence to calculated the turbulence parameters; applying limited velocity chemical reaction model and one-step reaction to calculated the reaction the gas oxidizer with the liquid fuel; applying the discrete transfer radiation model to simulate the heat transfer. The structure model could be properly simplified to simulate the combustion flow field. During the numerical simulation, there were applying the curvilinear coordinates for the computational field; applying First Order Upwind format to disperse the equations; applying PISO algorithm method to solve pressure-velocity coupling.The combustion flow field was simulated to compare and analyze the combustion flow fields during ten seconds between two different reactors. The flow field was simulated in one of the reactors by increasing the mass flux, which was obtained several results as follows: 1. In the initial reaction period, the flow field was changed more fiercely in the smaller reactor. 2. With the increase of the entrance of mass flux, the mixture of the fuel and oxidizer was quickened that increased the chemistry reaction rate and raised the temperature, and fluctuated the pressure largely in the whole reaction and the reaction was under an unsteady state in a long time. At the same time, the combustion flow field was also simulated under four different conditions of mass flux and initial temperature respectively, which obtained several results as follows: 1. The more the entrance of mass flow was, the higher the temperature obtained, and the more the combustion products got in the reactor. 2. The higher the initial temperature was, the higher the temperature obtained, but the quantity of the products had nothing to do with the initial temperature.Through the numerical simulation, it could be more reasonable to design the experimental projects, shorten experimental period and reduce experimental cost. It provided an important reference value with further designing the structure and enhancing the system efficiency.