Multi-scale Modelling of Structured Reactors

The overall objective is to research methods for the efficient simulation of structured reactors using models that can capture as much of the real micro scale phenomena as possible within the constraint of running in a realistic amount of computer time. The problem of modelling a complete reactor can be visualized as one of multi-scale modelling. Taking monolith reactors as an example, at the molecular level (micro-scale) there are the mechanistic models for the reaction kinetics. The meso scale can be defined as the channel level, in which the diffusion and reaction steps in the washcoat are considered, as is the mass and energy transfer between the fluid in the channel and the solid wall. The macro-scale is defined as the entire reactor that is modelled as a continuum. The challenge is to determine a method to capture the micro-scale information in the macro-scale model. Furthermore, the micro-scale model will be based on data determined in an appropriate experimental apparatus. In this study, the use of data based models for the monolith reactor and a gauze type reactor are explored. The information for the small scales is pre-computed and stored in a look-up table, which is accessed during execution of the macro-model. Through the analysis of the CFD simulation, it has been shown that this method can reduce the computation time significantly with good results.