Steffen Tischer

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This work focuses on the development and improvement of numerical tools for the simulation of catalytic monolith reactors. These simulations cover detailed descriptions of reaction mechanisms, transport in gas-phase and washcoats, fluid flow in single channels, and the entire reactor. In DETCHEM MONOLITH , the concept of building a transient model of the(More)
The ultimate goal in the numerical simulation of automotive catalytic converters is the prediction of exhaust gas emissions as function of time for varying inlet conditions, i.e. the simulation of a driving cycle. Such a simulation must include the calculation of the transient three-dimensional temperature-field of the monolithic solid structure of the(More)
Numerical simulations are increasingly assisting research and development in the field of emission control of automotive vehicles. Our work focuses on the prediction of the tail-pipe emissions, based on a numerical simulation of the automotive catalytic converter. Besides the prediction of the tail-pipe emissions, an understanding of the processes occurring(More)
An experimental and kinetic modeling study on the Ni-catalyzed conversion of methane under oxidative and reforming conditions is presented. The numerical model is based on a surface reaction mechanism consisting of 52 elementary-step like reactions with 14 surface and six gas-phase species. Reactions for the conversion of methane with oxygen, steam, and CO2(More)
2-D convection-diffusion, reacting flows in a single channel of catalytic monoliths are investigated. The fluid dynamics are modelled by a steady state, boundary-layer equations, which is a large system of parabolic partial differential equations (PDEs) with nonlinear boundary conditions arising from the coupling between the gas-phase and surface processes.(More)
Water-gas-shift (WGS) and reverse water-gas-shift (RWGS) reactions are numerically investigated in a stagnation-flow on a porous Rh/Al 2 O 3 catalyst. External and internal mass transfer effects are studied using three different models for the mass transport and chemical conversion inside the porous catalyst: the dusty-gas model, a set of reaction-diffusion(More)
Light-off of the partial oxidation of methane to synthesis gas on a rhodium-coated cordierite honeycomb monolith at short contact times is studied experimentally and numerically. The objective of this investigation is a better understanding of transient processes in catalytic oxidation reactors. The numerical simulation predicts the time-dependent(More)
for his very helpful guidance and scientific mentor. I also thank Dr. Huayang Zhu (Colorado School of Mines,Golden, USA) for his help regarding the dusty-gas model implementation. I gratefully acknowledge Dr. Canan Karakaya for her explanations on stagnation-flow reactor experiments and reaction mechanisms. I thank Julian Bär for discussions on(More)
The simultaneous generation of syngas (H 2 and CO) and power is a promising new application of an internal combustion engine. Due to the abundance of possible combinations of engine operating parameters that influence the outcome of reactions, an analysis of syngas production solely by empirical experiments is impractical. Therefore, it is essential to(More)