Asymptotic Simulation of the Four-Step Global Kinetics of Hydrocarbon/ Air Mixtures Under Flow Reactor Conditions

Abstract

The complete evolution of the one-dimensional, steady, convective-reactive combustion process of hydrocarbon/ air mixtures with the four-step semi-global kinetic mechanism of Hautman, Schug, Dryer, and Glassman, is simulated by using large activation energy asymptotic analysis. The analysis identifies four major regimes, which respectively represent the initial fuel pyrolysis and the subsequent oxidation of ethylene, hydrogen and carbon monoxide, as well as fifteen sub-regimes embedded within them. Transition between different sub-regimes is controlled by temperature variation as well as the generation and thereby availability of the reactants relevant to the specific sub-regimes. The structure is typical of that of thermal explosion, with the fuel pyrolysis regime dominating the physical extent of the process, and the highly-exothermic oxidative reactions being localized downstream of it. Reasonable agreements exist with the numerically-computed results