Theoretical and experimental investigation of the flow in catalytic converters

In response to the increasing use of catalytic converters for meeting exhaust emission regulations, considerable attention is being directed towards improving their performance. One of the main factors affecting catalyst performance is the velocity distribution of the exhaust gases entering the reactor substrate. Thus optimisation of catalyst performance will require a detailed understanding of the flow fields that exist in catalyst assemblies. The cost and time advantages of computational modelling over experimental analysis has meant that CFD is increasingly being utilised as a design tool. Although validation against experimental data has been claimed by several authors, few systematic validation programmes have been carried out. The present paper includes such a programme for axisymmetric catalyst geometries. Experimental results are compared with CFD predictions, produced using approaches commonly adopted within industry. Significant discrepancies between experimental and predicted results are reported.