in Wiley Online Library (wileyonlinelibrary.com).Due to computational time limitations, fully resolved simulations using the two-fluid model of the flow inside industrial-scale fluidized beds are unaffordable. The filtered approach is used to account for the effect of small unresolved scales on the large resolved scales computed with ''coarse'' realistic meshes. Using a fully resolved simulation, we highlight the need to account for a subgrid drift velocity to obtain the correct bed expansion when using coarse meshes. This velocity, defined as the difference between the filtered gas velocity seen by the particle phase and the resolved filtered gas velocity, modify the effective relative velocity appearing in the drag law. We close it as a correction of the resolved relative velocity depending on the filtered particle concentration and the filter size. A dynamic procedure is used to adjust a tuning parameter. Bed expansion obtained with a posteriori test on coarse-grid simulations matches well to fully resolved simulations. V V C 2011 American Institute of Chemical Engineers AIChE J, 58: [1084][1085][1086][1087][1088][1089][1090][1091][1092][1093][1094][1095][1096][1097][1098] 2012

No abstract

CFD simulations have been carried out in a full three-dimensional, unsteady, Eulerian framework to simulate hydrodynamic/thermal coupling in a bubble column with internals. A first part of the study, dedicated to the hydrodynamic/thermal coupling in liquid single-phase flows, showed that assuming constant wall temperature on the internals constitutes a reasonable approximation in lieu of comprehensive simulations encompassing shell flow and coolant flow together. A second part dealing with the hydrodynamics of gas-liquid flows in a bubble column with internals showed that a RNG k-e turbulence model formulation accounting for gas-induced turbulence was a relevant choice. The last part used these conclusions to build a hydrodynamic/thermal coupling model of a gasliquid flow in a bubble column with internals. With a per-phase RNG k-e turbulence model and assuming constant wall temperature, it was possible to simulate heat transfer phenomena consistent with experimentally measured heat transfer coefficients.