Ahmadreza Abbasi Baharanchi, Seckin Gokaltun, George Dulikravich, Performance improvement of existing drag models in two-fluid modeling of gas–solid flows using a PR-DNS based drag model, Powder Technology, Volume 286, December 2015, Pages 257-268, ISSN 0032-5910, http://dx.doi.org/10.1016/j.powtec.2015.07.001.
Abstract: This paper investigates a new drag model for the simulation of the fluidization of fluid catalytic cracking (FCC) particles with air in a fluidized bed using the two-fluid model (TFM) within the Multiphase Flow with Interphase Exchanges (MFIX) code. A cohesion index parameter based on the interparticle cohesive forces has been implemented in the MFIX-TFM code. This index is used as a switching criterion between a particle resolved drag model developed by Tenneti et al. (2011), and some of the drag models available in the MFIX for homogeneous particles, namely the Gidaspow, Syam–O’brien, and Wen–Yu models. The proposed drag correlation in this paper implements an indirect method of introducing interparticle cohesive forces to our TFM simulations. Significant improvement in the solid volume fraction profile along the riser was obtained for all of the drag law combinations, depending on the conditions set in the switching procedures. In the best case, the utilization of the Gidaspow and TGS models resulted in a 60% improvement in maximum deviation of numerical results from the available experimental data. The proposed model can be used in simulations of fluidized beds, where standard models fail to produce accurate results even on extremely refined computational grid, especially for Geldart A type particles that may exhibit strong clustering behavior.
Keywords: Multiphase flow; CFD; MFIX; Drag model; Two-fluid; Fluidized bed