Transient heat and mass transfer in two monolith reactor passage geometries
Ryan, Michael J.
Master of Science
Transient two dimensional mass and energy balance models of a monolith reactor are formulated and solved using a combination of analytical and numerical algorithms. The reactor passage has three distinct phases: the void phase where the reactant gases flow, the porous catalytic layer where the reactants diffuse and react, and the nonporous solid substrate layer. The concentration and temperature profiles are computed using a Fourier series solution for the fluid equations and a finite difference method of lines algorithm for the solid equations. Inter- and intra-phase heat and mass transport are quantified in terms of effectiveness factors and Sherwood and Nusselt numbers. A parametric sensitivity analysis for the automobile exhaust converter is carried out for two passage geometries: cylinder and parallel plate. These two reactors are compared under similar conditions to evaluate relative converter performance in terms of light off time and final conversion and effect of radiation.