Turbulent combustion of a uniform mixture and the formation of toxic substances

Turbulent combustion of a uniform mixture and the formation of toxic substances is examined. A model is constructed on the basis of the hypothesis that the fundamental process of oxidation takes place in narrow zones, while complete combustion of the fuel and the formation of nitrogen oxides occurs throughout the entire volume of the weakly nonequilibrium combustion products. The first stage is described using the equation for the probability density of the temperature. Its solution is analyzed, and it is shown that the average propagation velocity of a plane flame is entirely determined by the conditions in its leading boundary (that bordering fresh mixture). The second stage of the process is described with the help of the equation for averaged concentrations. The averaged values for the reaction rates are computed on the basis of results for the probability density of the temperature.