Drag coefficient and Nusselt number for porous particles under laminar flow conditions

This work studies three-dimensional numerical simulations of heat and fluid flow past and through porous particles. Its main objective is to investigate the influence of particle porosity on particle-averaged drag coefficient and surface-averaged Nusselt number numerically. Reynolds numbers considered are in the range of 10 < Re < 250 and up to 450 for specific porosities. Fluid flow features inside the particles are explored using an immersed boundary method. For this purpose, the particle porosity is modelled using agglomerates of small particles of spherical or cubical shape, respectively. This provides variation of the specific surface area while porosity is kept constant. The simulation results show a significant influence of porosity and Reynolds number on drag coefficient and Nusselt number. For these relationships new formulae are derived and compared to data from the literature. (C) 2017 Elsevier Ltd. All rights reserved.