Sub-grid Deconvolution Approach for Filtered Two-Fluid Models and the Application to Fluidized Gas-Particle Suspensions

Abstract

In our prior study [9], an a-priori analysis on the spatially-filtered two-fluid model (TFM) was presented for turbulent gas-solid flows, where the unresolved terms were modeled by an approximate deconvolution model (ADM). With such an approach, an approximation of the unfiltered solution is obtained by repeated filtering allowing the determination of the RSFS (resolved sub-filter scales) contribution of unclosed terms of the filtered equations directly. In the present study, this ADM-TFM approach is implemented in an a-posteriori manner for the coarse grid simulation of unbounded fluidization of Geldart type A particles. The ADM-TFM predictions of the domain averaged slip are in fairly good agreement with the fine grid reference case previously published in literature [3] and do not show a notable grid-dependency. Compared to TFM simulations using the same grid resolution, the ADM-TFM approach does only require marginally more computational resources but yields considerably better agreement with the fine grid data.