Steffen Tischer

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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)
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)
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)
Background: Solid-oxide fuel cells (SOFCs) have gained substantial interest in recent time as high efficiency electrical sources. A unique combination of advantages such as high reaction kinetics, poison tolerance, utilization of inexpensive catalysts, high power density, fuel flexibility and low emissions have helped SOFCs find application in the(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)