Laminar Flow - Difference Between Helical and the SMX-Types of Mixer

The Helical Mixer is a very simple and versatile static mixer.  Each mixing element of a helical mixer is essentially a plate twisted into a shape of a helix (hence its name) and attached to the next at a 90 degree angle about the axial.

As 2 fluids or more enter a helical mixer, the first element divides the flow into 2 parts.  Along the first element, radial mixing happens.  Then the flow enters the second element, and the flows are further split into 2 and mixed radially.  This continues on and on until full mixing is achieved.

Helical Mixing - Laminar Flow

The mixing is gentle, which is good for fluids that cannot afford to be sheared too much, especially non-Newtonian fluids that need to maintain their physical properties.

One disadvantage however, is that helical mixers may tend to require more elements than other mixers to achieve a good homogeneity, which comes at the cost of real estate or space.

Cross Section Mixing Illustrations After 1 Element, 2 Elements, 3 Elements, and so on. (Taken from http://www.samhwamix.com/)

The diagram above gives a clear indication of visual homogeneity after each element.  Decent mixing probably starts to happen by the 8th element, although streaks can clearly still be seen.


Solution?
An alternative to Helical Mixer could be the SMX-type mixer.  Within a short distance and a smaller number of elements, the mixer is able to thoroughly mix highly viscous fluids as shown in the diagram below:

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