An extremum variational principle for some non-linear diffusion problems

Abstract

An extremum variational principle for two non-linear boundary value problems is formulated. The first boundary value problem corresponds to the coupled diffusion reaction with high-order kinetics. The second boundary value problem describes zero-order chemical kinetics in a single catalyst pellet with Robin boundary conditions at the pellet's outer surface. For both problems, approximate solutions and their error estimates for several values of the parameters are obtained. © 1990.