Design Modifications to SMX Static Mixer for Improved Mixing
Andrew Hrymak, Shiping Liu, Philip Wood
McMaster University
Canada

Keywords: mixing, static, SMX

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Laminar flow and mixing in SMX static mixers were studied using the CFD tool FLUENT 5. Mixing quality was visualized by particle tracking. A frame indifferent parameter was used to classify the flow types in the SMX mixer. All three typical flows (simple shear, pure elongation and compressive) appear within the flow field of an SMX mixer. The strain rate distribution in the SMX mixer is very non-uniform. Small strain rate appears in the cross sections where crossing bars are sparse. This low level of strain rate provides poor mixing, especially for dispersive mixing. To improve the mixing in the SMX mixer, several modified geometries were examined. Results showed that appropriate arrangement of cross-bars increases the average and peak strain rate as well as making the strain distribution more uniform than standard SMX mixer. The rate of mixing improved in some of the proposed geometries, as compared to standard SMX designs.