M.S. Thesis Presentation by Cynthia Phillips
Monday, July 1, 2002

(Dr. Andrei Fedorov, advisor)

"Model-Based Design Optimization of Catalytic Mircorreactors and Chemical Sensors"


This study focuses on modeling of fluid mechanics and mass transport to determine the optimal designs for heterogeneous micro-reactors and chemical sensors.  The first part of this study is the minimization of catalyst loading in micro-reactors through optimal structuring of the catalytically active surface.  The high cost of catalyst surface is the motivation to minimize the catalyst surface in parallel with searching for a less expensive catalyst option.  The results of the model have shown that the catalyst loading can be reduced drastically in  diffusion-limited heterogeneous reaction systems, while the conversion rate remains essentially unchanged by using fractals for spatial distribution of the catalyst load.  This compensation in rate can be attributed to the proper introduction of singularities in the transfer boundary.  This optimal fractal structuring was tested under pure diffusion, and forced and natural convection.

The second part of this study addresses the optimization of geometry and operating conditions of an Infrared Evanescent Wave chemical sensor, both in binary and multicomponent diffusion modes.  The model has revealed the rate controlling parameters of the response time and provided guidelines for sensor design and optimization.  New “optimal” geometries were proposed and a global optimum criteria was developed.