Mixer barrier-embedded

M 80] [P 70] From prior experience with the chaotic screw extruder, it was estimated that the presence of the barrier structures in the barrier-embedded mixer accounts for about a 10% reduction in flow rate as compared with the slanted grooved mixer [58], Thus, a large mixing improvement is given at the cost of only a small reduction in flow rate. 

M 80] [P 70] Cross-sectional images of the flow patterns, gained by confocal microscopy, demonstrate the interfacial stretching and hence are indicative of mixing in the barrier-embedded mixer [58], At the non-barrier entrance structure clearly the helical flow induced by the slanted grooves is evident. In the barrier... 

Based on these considerations, a planar version of the chaos screw was designed with micron-sized dimensions, the barrier embedded micro mixer [3, 58],... 

Mixer 80 [M 80] Barrier-embedded Micro Mixer with Slanted Grooves... 

In this barrier-embedded micro mixer, oblique grooves, placed at the channel s floor, and barrier structures at the channel ceiling replace the flights and barriers of the chaos screw [58], The placement of the structures, however, is not essential for the functions. The positions at the floor and ceilings may change without loss of performance two-sided structures are expected to exhibit improved mixing over single-sided structures. The barriers are placed periodically so that barrier-free zones intersect. 

Mixer type Barrier-embedded micro mixer with slanted grooves Groove tilt angle 45°... 

This barrier-embedded micro mixer was made with helical static elements, resembling the internals of a Kenics mixer, and barrier structures at the channel ceiling [3]. 

Figure 1.163 Schematics of (a) the top view of the Kenics micro mixer with detailed dimensions, (b) the 3-D view of the barrier-embedded micro mixer and (c) the 3-D view of one mixing element with detailed dimensions [3] (by courtesy of IOP Publishing Ltd.). 

Figure 1.166 Normalized average intensity changes along the down-channel direction of three micro-mixer devices with barrier-embedded, slanted grooved and T-channel structures at (a) Re = 0.228, (b) 0.457, (c) 0.685 and (d) 2.28 [58] (by courtesy of IOP Publishing Ltd ).

M 81] [P 70] A plot of the normalized intensity versus the down-channel length clearly shows that the mixing efficiencies of the devices have the following sequence barrier-embedded helical mixer > helical mixer pipe mixer (see also Figure 1.165) [3]. The relative degree of mixing performance is lower for the pipe mixer than for the other two helical mixers. This is most evident for the three plots with Re > 13.96. 

Figure 1.167 (a) Characteristic mixing length of all three micro devices and (b) detailed view of the mixing length of the barrier embedded and slanted grooved micro mixers only, as a function of the flow regime, (c)... 

S. S., A barrier embedded chaotic micro-mixer, J. Micromech. Microeng. 2004, 34, 798-805. 

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