Investigations Into Numerical Methods Of Chemical Nonequilibrium Flow And Its Application To Simulation Of Shock-induced Combustion Phenomena

The coupling of fluid dynamics and chemical kinetics results in a variety of complex phenomena. A computational study has been conducted for high-speed reacting flows, especially for shock-induced combustion. Using a new numerical method of simulating chemical nonequilibrium flow with time-splitting method, the physical processes of flow and chemical reactions have been decoupled. As a result, the mature numerical methods of simulating the calorically perfect gas can be directly used in the flow part of chemical reacting flow; while the part of chemical reaction can be solved by many stiff ODE solvers. A finite difference method based on MUSCL scheme has been used for simulating the shock-induced combustion experiment conducted by Lehr in detail. The effects of reaction mechanism, which have been studied in my paper, can be crucial for the numerical simulation of reacting flow. The adiabatic, constant volume explosion model has been employed for approximating the reaction induced time and the energy release time. The two time scales can explain the effects of reaction mechanisms on the numerical results. The effects of computing grids and numerical scheme also have been studied. The diffusion of numerical scheme can affect the standoff distance of shockwave. Three stiff ODE solvers also have been compared. For the ease of computing flow field in complex geometry, a cell-centered finite volume procedure on unstructured meshes has been developed. With this method, the shock-induced combustion experiments conducted by Lehr and a standing stable ODW (oblique detonation wave) triggered by a wedge have been studied. The numerical results agree well with experiments or numerical results computed by some other authors.