Influence of monolith catalyst configuration on gas flow uniformity in automotive catalytic converter

The gas flow maldistribution in the three-way catalytic converter (TWC) negatively affects the conversion efficiency. A two-dimensional mathematical model for the steady gas flow within the TWC was developed to investigate the influence of the monolith configuration on the gas flow uniformity and pressure loss. A commercial Computational fluid dynamics (CFD) software PHOENICS 3.3 was used to numerically simulate the gas flow. The simulation results showed that the monolith with spherical and conical heads had much better flow uniformity than the ordinary flat surface. especially at high inlet velocity. Moreover, conical head monoliths with cone angles of about pi /2 to 2 pi /3 had better flow uniformities compared to the other configurations. An experimental system was developed to measure the flow field and pressure loss in the TWC. The experimental data verified the optimization results.