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An analytical study has been performed to investigate the use of a one-dimensional combustion model for transient premixed flames under conditions similar to those occurring in a sparkignition internal combustion engine. The model consists of the numerical integration of the basic conservation equations for mass, momentum, energy, and species with the effects of turbulence modeled by the use of a turbulent diffusivity. In order to evaluate the effects of some of the assumptions and identify the significant parameters, a simplified system consisting of constant volume adiabatic combustion was considered. With simple chemical kinetics and constant turbulent diffusivity, there are three parameters in the problem: a non-dimensional speed of sound, a non-dimensional temperature rise due to combustion, and a Damkohler parameter relating diffusion and chemical reaction rate effects. Two types of flames were modeled, a flat flame in linear coordinates and a cylindrical flame.

The reaction of ethylene in engine exhaust gases has been studied using a turbulent plug flow reactor. The effects of ethylene, oxygen, and nitric oxide concentrations and of temperature on the reaction were investigated. Nitric oxide was found to be consumed in the reaction and partially converted to nitrogen dioxide. For temperatures up to 649 °C, little formation of carbon dioxide was measured for a reaction time of 140 ms. Increasing the oxygen concentration above 4% gave no increase in the oxidation rate. The Kinetics of the reaction were such that it was not possible to describe the reaction with a simple Arrhemus rate expression. The only other hydrocarbon found was a trace of acetylene at a reaction temperature of 649 °C.