Numerical simulation of diffusion-controlled solid-state reactions in spherical particles

The three-dimensional time-dependent diffusion equation, subjected to a chemical reaction at the interface of the reacted layer and unreacted core, used for simulating diffusion-controlled solid-state reactions is solved by a finite volume method in a body fitted curvilinear co-ordinate system. The simulated reaction zone is seen to advance towards the center of a spherical particle. The concentrations of reactants and product are also predicted. Within the reacted zone, the simulated diffusion rates at different spherical cross sections reveal a clear picture of the unsteady diffusion process. The predicted kinetic curves at different conversion constants help to understand the kinetics of diffusion controlled solid-state reactions in spherical particles.