Design modifications to SMX static mixer for improving mixing

Laminar mixing in SMX static mixers and the effect of geometry on mixing are studied using computational fluid dynamics. A frame-indifferent parameter is used to classify the flow types in the SMX mixer. All three typical flows (simple shear, pure elongation, and squeezing) appear within the flow field of the SMX mixer. The strain rate distribution in the SMX mixer is observed to be very nonuniform. A mixing element with 10 crossbars shows the best mixing quality, followed closely by the standard SMX mixing element with eight crossbars. The improved designs of the mixing element increase the average and peak strain rate, and provide a more uniform strain rate distribution and faster mixing rate compared to those of the standard SMX mixer. (c) 2005 American Institute of Chemical Engineers AIChE J, 52: 150-157, 2006.