Microtomography-based numerical simulations of heat transfer and fluid flow through beta-SiC open-cell foams for catalysis

摘要

beta-SiC open-cell foams are promising materials for catalytic supports with improved heat and mass transfer at moderate pressure drops. In this work, 3-dimensional (3D) models of a 30 ppi (pores per inch) beta-SiC open-cell foam were generated using X-ray microtomography data. The resulting foam models were then used for finite element analysis (FEA) and computational fluid dynamics (CFD) simulations of heat transfer and fluid flow on the pore-scale. The FEA results demonstrate that (i) the overall effective thermal conductivity from direct simulations is comparable to the results estimated by experimental measurement, and are in the order of 10(-1) W m(-1) K-1 and (ii) thermal transport through fluid-saturated beta-SiC foams depends on the solid-to-fluid conductivity ratio. By employing realistic foam models, pore-scale CFD simulations of fluid flows revealed the microscopic characteristics of laminar flow through open-cell foams. The anisotropic feature of realistic foam models promotes the axial and radial mixing of fluids in and after the foam element. The diffusion coefficient of laminar flow within foams was estimated at 10(-4) m(2) s(-1), which is much larger than the molecular diffusion coefficient in a typical laminar flow in an open channel. (C) 2016 Elsevier B.V. All rights reserved.