AbstractThe transient light-off behavior of monolithic catalytic conveners after a cold start is critical to their overall performance. A novel two-dimensional equivalent continuum model was developed to describe the transient operation of these chemical reactors. The modeling equations constitute a system of coupled PDEs whose numerical solution imposes large memory and computational time requirements. A systematic approach was followed to vectorize the application code so that it can run efficiently on a CRAY-2 vector processor. Simulation results indicated that non-uniform flow distributions and ambient heat losses can have significant adverse effects on the light-off performance of the catalytic conveners.