A Density-Weighted Multi-Phase Model for Turbulent Diffusion Flames

A reacting multi-fluid model, based on the Favre-averaged separate transport equations for reacting gas-liquid “multi-phase” flow, is presented. New density-weighted (Favre-averaged) transport equations for multi-phase mixture fraction f͂ and its variance g are derived. The new multi-fluid transport equations for f͂ and g are equally applicable to spray flames as well as liquid metal fuel combustors. The fuel spray is discretized into a number of size groups; each group is considered as a separate “fluid” or “phase”. A pdf approach, to the reaction process, is adopted. An evaporation variable e is introduced, which is a measure of a nonequilibrium phase state, defining a two-variable pdf as a function of f and e. The instantaneous thermo-chemical properties are computed from a nonequilibrium model. The predicted results, using the present density-weighted multi-fluid model, for an airblast kerosene spray flame are compared with corresponding experimental data. The present multi-fluid model results are in good agreement with the corresponding experimental data for the whole spray flame length.