posted on 2021-04-01, 10:27authored byBaggie
W. Nyande, Kiran Mathew Thomas, Richard Lakerveld
Kenics static mixers enhance mixing under laminar flow conditions.
The ideal static mixer achieves efficient mixing at a low pressure
drop. A modified design of the Kenics static mixer is analyzed, featuring
gaps between the mixing elements, which can achieve the same level
of mixing as the conventional design but with fewer mixing elements
and a substantially lower pressure drop. The mixing effects at the
entrances and exits of the mixing elements are enhanced by the introduction
of gaps between the elements. The performances of mixers based on
the right–left and right–right configurations with different
gap lengths are characterized in terms of pressure drop, coefficient
of variance of concentration, residence time distribution, and extensional
efficiency with computational fluid dynamics simulations. Furthermore,
the coefficient of variance of concentration is measured experimentally
with several three-dimensional (3D) printed devices. The gaps reduce
the mixing length when the design is based on the right–right
configurations, and the gap-to-diameter ratio is 0.5 or 1.0 compared
to the corresponding conventional design. Furthermore, Taylor dispersion
is suppressed with the introduction of gaps, which enables a narrower
residence time distribution. The presence of gaps between mixing elements
introduces an additional degree of freedom, which can be utilized
to strike a compromise between the required mixing length and pressure
drop.