Photocatalytic NOx abatement for diesel engines

Marco TORRESI, Politecnico di Bari

The NOx abatement in Diesel engine has been studied by means of both numerical and experimental activity. The first part of the study has been focused on the characterization of the numerical model applied to a catalyst of a passenger car. Three-dimensional steady and unsteady numerical simulations of the flow field and chemical reactions within a conventional diesel catalyst have been performed. The flow characteristics within the catalyst has been investigated by means of steady three-dimensional Reynolds-Averaged Navier-Stokes approach and a transport equation for each of the incoming chemical species have been used. The catalyst considered has been split in three main zones: inlet, catalytic monolith and outlet, where catalytic monolith has been treated as a porous media. The results in three different working points have been reported. Evidences on how the non-uniform flow distribution affects the catalyst efficiency have been described. Moreover, the fluid-dynamic solver has been coupled with a chemical reaction mechanism in order to be able to catch the chemical surface reaction within the catalyst. The here described numerical approach will be extended to a photo-catalyst where a radiation equation will be implemented and coupled with the flow-chemical solver. The kinetic parameters of the chemical reactions will be affected by the radiation field giving an estimation of the catalyst performance. The experimental part of the study includes a chemical reactor to test the performance of the photocatalytic material. The experimental results will be used to support the numerical activity and to validate the numerical models.

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