Improving the accuracy of two-fluid sub-grid modeling of dense gas -solid fluidized flows

In gas-solid fluidization highly resolved simulations (HRS) with microscopic two-fluid modeling (mTFM) are frequently employed for deriving sub-grid closures for filtered parameters that are required in filtered formulations useful in large scale simulations of real flows. This work intends to contribute for improving the accuracy of underlying HRS raw data upon which the accuracy of sub-grid closures relies on, particularly regarding dense gas-solid fluidized flows. The accuracy of mTFM is improved by incorporating interparticle frictional effects. The accuracy of correlation to filtered parameters is improved by accounting for macro-scale conditions and by enforcing a three-independent variable approach. HRS were per formed in a periodic domain applying the mTFM of MFIX properly modified by the inclusion of a literature trustworthy interparticle friction model. Results showed that accounting for macro-scale conditions and for three independent variables considerably contributes for improving correlation resolution, while the effect of interparticle friction was only marginal. (c) 2020 Elsevier Ltd. All rights reserved.