Numerical Simulation Of High Energy Fuel Combustion Flow Field And Structural Design

Li/SF6 fuel system has the advantage of high energy density, safe, non-toxic, stable reaction process and free from external influences, etc. Whether it is applied to underwater power systems or space propulsion power systems or other special circumstances, the system still has obvious advantages. Therefore, research in this area has important practical significance.Li/SF6 combustion reaction process is a complex series of physical and chemical processes. It consists of a gas-liquid chemical reaction, Gas-gas chemical reaction, evaporation and condensation of liquid lithium and lithium vapor. Besides, during this process, there will be high-temperature gas cracker, and combustion products will appear in the gas, liquid, solid-phase material accompanied by phase change. Li/SF6 combustion system has two forms of reactions which are the surface injection and the submerged injection. In this dissertation, in order to simulate the non-steady-state combustion for the surface injection system of Li/SF6, used eddy dissipation model (Eddy-Dissipation Modal, referred to as EDM model) simulation of combustion processes, the standard k ?εmodel for viscous model, Eulerian particle model for the formation of solid product are applied to simulate the temperature distribution in the reactor, the combustion flow field in the basic situation and the resultant of the settlement process. In the process of numerical simulation, body-fitted coordinate system is used to disperse the calculation regional space, and discrete first-order upwind scheme is introduced to disperse the controlling equations. Wall treatment adopts wall function method, and PISO algorithm is used to calculate the velocity pressure coupling problem.Through the numerical simulation of the combustion of the simplified structure reactor, when it is unreacted (0.5s), initial reacted (2s) and has been reacted for10s, it can obtain the corresponding temperature fields, pressure fields, chemical reaction rates and the component distributions, etc. in the reactor are analyzed. And compare the influence of different conditions of mass flux and initial temperature of lithium on temperature field and mass integral of products. The results are: the quicker the entrance mass flow is, the higher the reaction temperature is; the higher the initial temperature is, the higher the reaction temperature obtains; the overall quantity of the products have noting to do with the initial temperature; the quicker the entrance mass flow is, more the combustion products get in the reactor.Based on the structural design, according to an investigation by the part of character of the reactants (Li and SF6) and the product (LiF and Li2S) of the reaction, the parameters and the stress of the kettle were calculated. Finally during the experiment for emerging nozzle clogging problems, analysis of the specific reasons for blocking the nozzle produced. In order to solve the nozzle clogging problem, we use the following several ways: preheat SF6, Increasing the nozzle aperture, improving the thermal conductivity of the nozzle, using porous anti-clogging technology, etc.The results of the simulation could make a guidance to design the experimental projects, shorten experimental period and reduce experimental cost. It provides an important reference value with further designing the structure and enhancing the system efficiency.