| The air pollution generated from mobile sources creates a large impact on the environment and on people's health. In order to meet the stringent emission regulations worldwide, aftertreatment devices are employed to reduce the toxic emissions emanating from the Internal Combustion engines in these mobile sources. In order to continually reduce emissions levels, it is essential to understand and develop more predictive aftertreatment models. Traditional devices are of the monolithic geometry consisting of small channels employing laminar flow. However, often the reaction rate expressions utilized in these models are derived from more conventional packed bed reactor experimental setups. The aim of this thesis is to develop a one-dimensional pseudo-homogeneous packed bed reactor model for this type of reactor setup built in collaboration with the Chemical and Petroleum Engineering Department at the University of Kansas. A brief summary of the pseudo-homogeneous model is presented in order to properly develop the chemical species and energy equations for dynamically incompressible flow in one-dimension. Furthermore, the chemical kinetics on the reduction reaction of nitric oxide by carbon monoxide over rhodium-alumina and platinum-alumina catalysts is investigated in detail. This is accomplished in order to validate the model using fundamentally correct reaction kinetics via a precise global reaction mechanism. Finally, parametric studies including the different model components are presented and the specific choice of model does not largely influence the conversion profiles because of the similar effective transport values. Also, it is found that a careful consideration of source terms are required to model reactions accurately. |
