A turbulence closure model for dilute gas‐particle flows

Abstract

Abstract A second order closure scheme is developed for the numerical prediction of isothermal, non‐reacting, mono‐dispersed, dilute gas‐particle turbulent shear flows. The model is based on the two‐equation (κ‐ϵ) turbulence model developed for calculating the analogous gas‐phase flows. Contrary to passive additives in a single phase flow, the particles will affect the turbulence structure of the continuous phase. Thus, the κ‐ϵ model has been modified to account for the presence of the dispersed particles. In particular, the particles increase the dissipation rate because of the relative velocity fluctuations between the two phases. New proposals for these added effects based on particle size and loading are added to these equations. The resulting model is used to compute the axisymmetric jet in its developing region. The calculated jet spreading rate, centre‐line velocity decay and entrainment rate are all in excellent agreement with published experimental data. Calculated turbulence quantities such as the kinetic energy and mean Reynolds shear stress are greatly reduced from their “clean jet” levels by the presence of the particles in good agreement with the available experimental data.