A PDF Based Approach For Modelling Dispersed Two-Phase Flows

The paper presents a PDF-derived Eulerian/Eulerian model for the prediction of dispersed two-phase (solid/gas) flows. Continuum equations for the dispersed phase are formulated from the Kinetic Model (KM) PDF transport equations. The Reynolds stresses of the dispersed phase are determined from an algebraic stress model (ASM) together with a KM-based transport equation for the turbulent kinetic energy (k(d)). The continuum equations for the continuous phase are assumed to be the same as those in the Eulerian two-fluid model; also turbulence in that phase is modelled by the standard k-epsilon model. The model equations are solved using the numerical framework of the two-fluid approach. Validation is accomplished by comparisons against experimental data for scalar mixing and shear layer cases. The predictions are in excellent agreement with measurements in the scalar mixing case, highlighting the abilities of the model to simulate the dispersion and turbulence dissipation. For the shear layer case, agreement with experimental data is generally good, although there is slight under-prediction of shear layer thickness in the high velocity stream. This however is a result of under-prediction of the carrier fluid turbulent energy rather than due to a shortcoming of the dispersion model.