Mixer electroosmotic

Mixer 3 [M 3] Electrokinetic Instability Electroosmotic Flow Micro Mixer, First-generation Device... 

Electrokinetic instability electroosmotic flow mixer, lst-generation device... 

This electrokinetically driven micro mixer uses localized capacitance effects to induce zeta potential variations along the surface of silica-based micro channels [92], The zeta potential variations are given near the electrical double layer region of the electroosmotic flow utilized for species transport. Shielded ( buried ) electrodes are placed underneath the channel structures for the fluid flow in separate channels, i.e. they are not exposed to the liquid. The potential variations induce flow velocity changes in the fluid and thus promote mixing [92],... 

This chaotic electroosmotic micro mixer has not been realized so far only a theoretical study on the principle of the device was made [28], A schematic was given which can serve as base for the future realization of such a device (see Figure 1.17). 

FIGURE 3.40 (a) Configuration of the experimental setup and white light microscopy image of an imprinted T-channel with a series of ablated wells, (b) Fluorescence images of electroosmotic flow past the mixer at flow rates of 0.06 cm/s [193]. Reprinted with permission from the American Chemical Society. 

Similar to the Qian and Ban s mixer in Ref. [20], this mixer also utilizes electroosmotic flow, which operates in the Stokes flow regime. As a result, the streamlines are rather insensitive to the variations in Re molds number. 

Figure 1. Schematics of the continuous chaotic stirrer developed by Kim and Beskok [25], The stirrer consists of periodically repeating mixing bocks with zeta potential patterned surfaces (a) and an electric field parallel to the x-axis is externally applied resulting in an electroosmotic flow (b). Combining a unidirectional (x-direction) pressure-driven flow (c) with electroosmotic flow under time-periodic external electric field (in the form of a Cosine wave with a frequency ra), a 2-D time-periodic flow is induced to achieve chaotic stirring in the mixer. Two fluid streams colored with red and blue are pumped into the mixer from the left and are almost well mixed after eight repeating mixing blocks for Re = 0.01, St = I2%, Pe= 1,000, and T = 0.8(d).

H.J. Kim and A. Beskok, Numerical Modeling of Chaotic Mixing in Electroosmotically Stirred Continuous Flow Mixers, ASME J. Heat Transfer 131(9) 092403 (2009). 

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