Modelling a transport equation of turbulent reactive mixing flow

The evolution of the single-point joint scalar probability density function(pdf) of two reactive scalars in idealized turbulent flows was examined by analytical conditioning and the introduction of appropriate scalar intermittency factors. Closure approximations are proposed for turbulent convection, molecular mixing and entrainment. For non-reactive flows, the closed pdf equation for a two-species turbulent mixing flow is investigated by applying it to the thermal mixing layer of a half-heated grid and to the two-scalar mixing layers behind a two-species grid, where each layer is equivalent to the thermal mixing layer of a half-heated grid. The closures used in the nonreactive case are used to predict the evolution of B chemical species statistics in a reacting flow system for which no experimental data is yet available. The closed scalar pdf equation is also applied to a homogeneous reactive grid flow, for which limited measured data exist; namely, the mean and root mean square concentration of the reactants. The predicted statistics of reactants is moderately close to the measured data.