I am also interested in semi-analytical solutions for combustion problems. On problem considered the cubic-autocatalytic scheme in a reaction-diffusion cell while another looked at the classical pellet problem. The basic idea was to approximate the governing partial differential equations by ordinary differential equations, which are amenable to the usual methods of combustion theory. Below are two papers of mine on this topic. Dr. Mark Nelson and myself have submitted a current ARC Discovery grant application on this topic. A new collaborator of ours is Prof. Venkat Subramanian , Tennessee Technical University, USA who is a expert on batteries, fuel cells and electrochemical systems.