Static Mixers to Promote Axial Mixing

A new class of static mixers is described. They are intended to homogenize feed streams subject to temporal variations in concentration or temperature. The general design approximates the axial mixing performance of a CSTR without need for moving parts. It does this by creating parallel flow paths with a wide variation in residence times. The residence times are chosen to approximate the exponential distribution of a CSTR. The devices do very little mixing in the radial direction and thus behave like completely segregated stirred tanks. They may be used advantageously in series with a conventional static mixer. Mechanically simple but effective designs are described for both laminar and turbulent flow. Experimental measurements on a four-zone mixer confirm the theoretical design and confirm that the residence time distribution is approximately exponential.