Simulation of gas–solid flows in riser using energy minimization multiscale model: effect of cluster diameter correlation

Abstract

Reduced effective drag is observed in gas–solid riser flows due to formation of clusters. Thus the cluster diameter correlation has a direct impact on the calculated drag and the hydrodynamics predictions. However, its effect has not been studied. Therefore in this study, the effect of cluster diameter correlations on the drag coefficient and simulation predictions is evaluated. A structure-based drag is derived using the EMMS model, and is used to carry out computational fluid dynamics (CFD) simulations for low solid flux fluid catalytic cracking (FCC) risers. The results are compared with those using the Gidaspow drag model, as well as experimental data and previous simulation results. The time-averaged axial and radial profiles of voidages are compared with the experimental data. The comparison shows that only the EMMS model is able to capture the axial heterogeneity with the dense bottom and dilute top sections. The cluster diameter correlation proposed by Harris et al. (2002) gives reasonable qualitative and quantitative agreement with the experimental data for axial voidage profile, particularly in the dense bottom section; however, the quantitative disagreements in the radial profiles persist.

@article{shah2011ces,
  title         = {Simulation of gas--solid flows in riser using energy minimization multiscale
                  model: effect of cluster diameter correlation},
  author        = {Shah, Milinkumar T. and Utikar, Ranjeet P. and Tade, Moses O. and Pareek,
                  Vishnu K. and Evans, Geoffrey M.},
  year          = 2011,
  journal       = {Chemical Engineering Science},
  publisher     = {Elsevier},
  volume        = 66,
  number        = 14,
  pages         = {3291--3300},
  doi           = {10.1016/j.ces.2011.01.056},
  url           = {https://www.sciencedirect.com/science/article/pii/S0009250911000765}
}