Mixing and chemical reaction in steady confined turbulent flames

A calculation procedure has been developed for solving the partial parabolic differential equation of turbulent flame spread. This procedure has been applied to the spread of flame behind a baffle in a plane-walled duct, with two distinct models for the kinetics of the reaction. In the first model, the time-mean reaction rate is related to the time-mean concentrations and temperature at the point in question by a bimolecular Arrhenius expression. In the second model, the local reaction rate is taken to depend also on the rate of break-up of the eddies by fits the experiemntal data better than the first; the eddy-break-up term appears to be essential if the dominance of hydrodynamic processes is to be correctly simulated. A third model of turbulent combustion is also described. It involves the calculation of the magnitude of the fluctuating concentrations, and correctly predicts themain features of turbulent diffusion flames. One of its implications is a finite reaction-zone thickness, even through there is no chemical-kinetic resistance.