A Study of the Effects of Various Flow Obstructions on Micromixing and Heterogeneous Catalysis in Biocatalytic Microchannels

The results of a numerical study of the fundamental interactions of engineering design and micromixing on conversion in packed microchannels are presented. Previously, channel-based microreactors made of molded silicon plastic were designed, fabricated, and experimentally tested. These reactors have enzymes immobilized on the channel walls by various methods including layer-by-layer nano self-assembly techniques. They also contain molded packing particles to add reactive surface area and to redistribute the fluid. An intuitive packing arrangement was used in experimental studies and modeled successfully by computer simulation. A computer simulation study has been conducted in order to understand how changes in packing arrangement and number of packing particles affect micromixing and conversion efficiency. The experimental reactors have been simulated using CFD-ACE+ multiphysics software. The focus of this study is to optimize the placement and number of packing to more efficiently meet conversion goals, taking into account micro fabrication and operational constraints. Microfluidic fundamentals such as Reynolds number (Re), shear stress, and pressure drop are also explored due to variations in design features. The micro scale dimensions of the channel cross section (125 by 500 micrometers) cause all flows to be laminar. Behavior in the range 0.1