Simulation of Flow Through Catalytic Aerogel Material Using Lattice-Boltzmann Methods

The automotive industry is driven by a need to address both environmental and fiscal challenges. Although the industry would like to move away from petroleum based power trains, it is not yet economically feasible. Therefore the industry is still focused on increasing the efficiency of the internal combustion engine and making it more environmentally friendly. Catalytic converters are pollution mitigation devices used in internal combustion powered automobiles to convert harmful exhaust gases to less potent gases through the use of a honeycomb supported washcoat containing expensive platinum group metals (PGM). This research project is part of a study to validate the efficacy of using aerogels to replace PGMs in automobile catalytic converters.  Aerogels are highly porous, thermally stable and can be made catalytically active which makes them attractive for pollution mitigation applications. The goal of this project is to develop a computational method for studying flow through aerogels to better understand their potential effectiveness as washcoats for catalytic converters. The Lattice-Boltzmann method, a computational fluid dynamics scheme which models fluid flow by utilizing modified kinetics to dictate particle motion, was used. The aerogel structure was simulated using scanning electron micrographs of aerogels. Code was developed to distribute catalyst particles throughout the simulated aerogel based on catalyst particle diameter and the specified amount of catalyst particles. The most important result from this research is the calculation of the percentage of fluid particle to catalyst particle interactions for a specified aerogel morphology and catalyst particle loading because it is related to how conducive the aerogel geometry is to efficient catalysis. Another important component of this research was to enhance the user interface of the program. The code will be used to compare different aerogel morphologies and determine the accessibility of the gas flow to catalytic sites as a function of morphology, catalyst size, and amount.