Numerical simulation of the Reynolds number effect on gas-phase turbulence modulation

The enhancement of the gas-phase turbulence intensity at high Reynolds number (Re) has been observed experimentally by Hadinoto et al., in dilute-phase particle-laden flows of non-massive particles (<= 200 mu m). This work attempts to assess the predictive capability of a two-phase flow computational fluid dynamics (CFD) model, which is based on the kinetic theory of granular flow, in capturing the trend in the gas-phase turbulence modulation as a function of Re. In addition, the model predictive capability in simulating gas-particle flow regime of moderate Stokes number (St(T)) and low Re is examined. The use of different drag correlations and turbulence closure models is explored for this purpose. The simulation results suggest that the current state of the two-phase flow CFD model is not yet capable of accurately predicting the Re dependence of the gas-phase turbulence modulation. The two-phase flow CFD model. however, is more than capable in yielding good predictions at both the mean and fluctuating Velocity levels for the case where the turbulence enhancement at high Re is not evident. (C) 2008 Elsevier Ltd. All rights reserved.