(407b) Sub-Grid Models for Gas-Particle Flows from Highly-Resolved 3D Simulations

Sub-grid models improve considerably the quantitative accuracy of coarse-grid CFD simulations of gas-particle flows. Earlier efforts on sub-grid models by Igci et al. [AlChE J., 54(6), 1431-1448, 2008] focused on one-marker models, where the sub-grid corrections were correlated in terms of filtered particle fraction (in addition to filter size). These models were mainly deduced from highly-resolved simulations of gas-particle flows in 2D periodic domains and a limited number of moderately-well-resolved 3D simulations. More recently, Milioli et al. [AlChE J., 59(9), 3265-3275, 2013] constructed two-marker filtered models, by including the gas-particle slip velocity as an important second marker, and analyzing results gathered from well-resolved simulations in 2D periodic domains.

In the present study, we have performed several highly-resolved simulations of gas-particle flows in 3D periodic domains. The results are then analyzed to construct sub-grid models for interphase drag and stress. The one-marker and two-marker 3D sub-grid models deduced in this study are qualitatively similar to those developed previously from 2D simulations; however, noticeable quantitative differences are observed. The new 3D filtered corrections are more suitable for practical coarse-grid, 3D simulations of commercial-scale devices.

Our presentation will describe the simulation results and discuss the attributes of the new sub-grid models.