Carrier-extraction from two rigid spheres in tandem

Unsteady mass transfer between two rigid spheres in tandem and a surrounding fluid flow with reversible second-order chemical reaction on the surface of the spheres has been analysed. The spheres have the same diameter and initial concentration. The dispersed phase reactant and product are insoluble in the continuous phase. The continuous phase reactant and product are insoluble in the dispersed phase. Axisymmetric, slow, viscous flow (Stokes flow) around the spheres was considered. The mass balance equations were solved numerically in spherical/bispherical coordinates systems by a finite difference nonlinear multigrid method. For moderate Pe number, Pe = 100, modified Hatta modulus, Ha(2) = 10, 100, 1000, and different values of the diffusion coefficients, the computations focused on the influence of the spheres spacing on the mass transfer rates. (C) 2009 Elsevier Masson SAS. All rights reserved.