Felix Birkhold

Analysis of the Injection of Urea-Water-Solution for Automotive SCR DeNOx-Systems: Modeling of Two-Phase Flow and Spray/Wall-Interaction

The selective catalytic reduction (SCR) based on ureawater-solution is an effective technique to reduce nitrogen oxides (NOx) emitted from diesel engines. A 3D numerical computer model of the injection of urea-water-solution and their interaction with the exhaust gas flow and exhaust tubing is developed to evaluate different configurations during the development process of such a DeNOxsystem. The model accounts for all relevant processes appearing from the injection point to the entrance of the SCR-catalyst:

Formation of Urea-Based Deposits in an Exhaust System: Numerical Predictions and Experimental Observations on a Hot Gas Test Bench

Using a generic configuration of an exhaust system, the formation of deposits due to urea-derived byproducts is examined. For this purpose, the temporal profile of the formation of deposits is visually observed and the resulting deposit composition is analyzed. Based on the experimental results, the most important deposit regime can be identified depending on the measured wall temperatures and is compared with the prediction of a suitable reaction mechanism.