[rob3]

hello to everybody!

i am trying to model a methane steam reforming reactor in cfx14.5. we are taking about a cilindrical tube 10mm diameter(10mm long) with a cylindrical pellet of catalyst inside of cilindrical shape 3mm D(3mm long). this is just a simple model to learn how to conigure cfx for solving the full scale one.
the problem consists of 3 chemical reactions, 3 kinetics models depending on partial presures and another quantities like T,abs P and Ki's, Ai's.

i already have done the next:
1. load all expresions including the kinetic models and other parameters, relating them with absP and T. no problem.
2. construct 3 chem reactions and enter the expresion for the kinetic model for each one (1).
3. for external cilinder make all boundaries:inlet,outlet,wall, and included a variable composition mixture of all compounds.
4. for the pellet i specify its solid domain, etc.

my problem is i don´t know how to make the program to asociate the chemical reactions to the pellet's walls only, and not to the entire volumetric domain.

i already tried:
a. to create a subdomain in the pellet, and in this make a source but equally didn´t work. in all cases cfx needs to be a volume where the reactions occurs.
b. i´m thinking in make a shell around the pellet and in its volume configure the reactions, but i don´t know how to stablish the boundaries of this shell so the flow can go in react and go out freely, while transfers heat to the pellet.

please help!

PD: te reactions are endothermic,there is a heatflux from the wall to the gas mixture. all reactions are in gas phase.

thank you all!