Lattice Boltzmann investigation of non-Newtonian fluid flow through a packed bed of uniform spheres

摘要

Non-Newtonian fluid flows through packed beds are very common in many industries; however, our understanding of this flow system is very limited. In this paper, a parallel Lattice-Boltzmann (LB) model is applied to simulate the power-law fluid flows through a packed bed of porosity 0.366 on a sub-particle scale. The packed bed is generated by means of discrete element method. The flows cover wide ranges of Reynolds numbers (0.1 Re 500) and power-law indices (0.6 n 1.4). In total, seventy sets of LB simulations are conducted under well-controlled conditions. The results indicate that the internal fluid velocity distribution within the packed bed shows that the flow behaviors vary for different flow regions and fluids corresponding to various pore structures. Also, both viscosity and shear stress show significant differences in pore and near-particle regions. Because of these complicated flow characteristics, the submerged objects model is selected to formulate a drag correlation with least assumptions. The comparison of the new correlation with others against experimental data shows that the new one is more accurate. The present framework provides a sound base to investigate the fundamentals governing the behaviors of non-Newtonian fluid flow through packed beds under different conditions. (C) 2018 Elsevier B.V. All rights reserved.