Numerical Simulation of Flame Propagation

Sammanfattning: The effects of the temperature and length, of the preheat zone, on the deflagration to detonation transition are investigated through numerical simulation. The Navier-Stokes equations, with a reaction term, are solved in one dimension. The time integration is a one-dimensional adaptation of an existing two-dimensional finite volume method code. An iterative scheme, based on an overlap integral, is developed for the determination of the deflagration to detonation transition. The code is tested in a number of cases, where the analytical solution (to the Euler equations) is known. The location of the deflagration to detonation transition is displayed graphically through the preheat zone temperature as a function of the fuel mixture temperature, for fixed exhaust gas temperature and with the preheat zone length as a parameter. The evolution of the deflagration to detonation transition is investigated for an initial state well within the regime where the deflagration to detonation transition occurs. Graphs displaying the temporal evolution of pressure, temperature, reaction rate, and fuel mass fraction are presented. Finally, a method for estimating the flame velocity during the deflagration and detonation phases, as well as the flame acceleration during the intermediate phase, is developed.