Numerical methods are used to investigate the transient, forced convection heat/mass transfer inside circulating spheres at low to moderate Reynolds numbers. The heat/mass balance equations were solved numerically in spherical coordinates system by a finite difference method. The values considered for the sphere interior Reynolds number are Re-int <= 1000. The computations were focused on the influence of the sphere Peclet number, Pe, and Re-int on heat/mass transfer rate for Pe/(1 + mu) <= 10(4) (C) 2010 Elsevier Ltd. All rights reserved.