Authors: Kay Wittig; Aakash Golia; Petr A. Nikrityuk
Addresses: CIC Virtuhcon, Department of Energy Process Engineering and Chemical Engineering, Technische Universitaet Bergakademie Freiberg, 09599 Freiberg, Germany ' Department of Mechanical Engineering, Indian Institute of Technology Guwahati, India ' CIC Virtuhcon, Department of Energy Process Engineering and Chemical Engineering, Technische Universitaet Bergakademie Freiberg, 09599 Freiberg, Germany
Abstract: This work is devoted to the three-dimensional numerical simulations of the heat and fluid flow past and through a porous spherical particle over a wide range of Reynolds numbers (20 < Re < 500) corresponding to the steady-state flow and different values of porosity varying between 0.62 and 0.92. The porosity of a particle is modelled using two approaches corresponding to a microscopic and macroscopic representation of the pores, respectively. Specifically, in the first approach the porous particle is represented by a cluster of small spherical particles distributed inside the porous particle. The second approach represents the porosity implicitly utilising the so-called permeability model, adopting the Blake-Kozeny equation to treat the fluid and heat flow inside a particle. The comparison of the two models showed good agreement for a porosity below 0.7. The analysis of numerical simulations showed that for a constant Reynolds number (Re < 100), with increasing porosity, the value of the drag coefficient decreases slightly. However, when the Reynolds number is increased (Re > 100) a local maximum in the drag force coefficient was observed for a porosity of about 0.76. On the basis of the results of simulations, expressions are derived and examined for the drag coefficient and the surface-averaged Nusselt number.
Keywords: 3D fluid flow; particle porosity; heat transfer; drag force; Nusselt number; permeability; numerical simulation; drag coefficient; porous particles; spherical particles.
Progress in Computational Fluid Dynamics, An International Journal, 2012 Vol.12 No.2/3, pp.207 - 219
Received: 08 May 2021
Accepted: 12 May 2021
Published online: 21 Jun 2012 *