In the present work three-dimensional steady and unsteady numerical simulations of the flow field and chemical reactions within aNOx Storage Converter (NSC) diesel catalyst have been made. In the first part of the paper, only the flow characteristics within a catalyst have been investigated by mean of a steady three-dimensional Reynolds-Averaged Navier-Stokes approach and a transport equation for each of the incoming chemical species. For flow simulations, the catalyst volume has been split in three zones: inlet, catalytic monolith, treated as porous media, and outlet, medium. The results have been reported in three different working points. Evidences on how the non-uniform flow distribution affects the catalyst efficiency have been described. In the second part, the fluid-dynamic solver has been coupled with a chemical reaction mechanism in order to catch the chemical surface reaction within a NSC catalyst. This coupled model has been validated according to the literature. Volumetric and superficial species concentration have been calculated imposing the site density and the kinetic of the reactions on a substrate Ba/Al2O3. NOx spatial distributions within the catalyst during a dsorption phase are reported. The model represent a reliable tool to investigate in detail the complex flow/chemistry interaction within the modern diesel engine catalysts.
Numerical simulation of the flow field and chemical reactions within a NSC diesel catalyst
FORNARELLI, Francesco;
2015-01-01
Abstract
In the present work three-dimensional steady and unsteady numerical simulations of the flow field and chemical reactions within aNOx Storage Converter (NSC) diesel catalyst have been made. In the first part of the paper, only the flow characteristics within a catalyst have been investigated by mean of a steady three-dimensional Reynolds-Averaged Navier-Stokes approach and a transport equation for each of the incoming chemical species. For flow simulations, the catalyst volume has been split in three zones: inlet, catalytic monolith, treated as porous media, and outlet, medium. The results have been reported in three different working points. Evidences on how the non-uniform flow distribution affects the catalyst efficiency have been described. In the second part, the fluid-dynamic solver has been coupled with a chemical reaction mechanism in order to catch the chemical surface reaction within a NSC catalyst. This coupled model has been validated according to the literature. Volumetric and superficial species concentration have been calculated imposing the site density and the kinetic of the reactions on a substrate Ba/Al2O3. NOx spatial distributions within the catalyst during a dsorption phase are reported. The model represent a reliable tool to investigate in detail the complex flow/chemistry interaction within the modern diesel engine catalysts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
