Electrohydrodynamic mixers

Figure 1.5 Schematic of the electrohydrodynamic mixer with T-channel and pairs of electrodes adjacent to the channel and perpendicular to the fluid interface generated [91] (by courtesy of RSC).

Mixer type Electrohydrodynamic mixer Wire electrode diameter 250 pm... 

In an electrohydrodynamic mixer, a DC electric field (400 kV/cm) is applied on two electrodes across a channel to induce secondary transverse flow for solution mixing. Explain why there is no problem of electrolysis. (2 marks)... 

Fig. 2 From [6] (a) Configuration of electrohydrodynamic mixer. Experimental images of mixing (b) initial condition, (c) after the application of a DC electric field of intensity = 4 X 10 V/m and (d) = 6-10 V/m...

An exanple of an electrohydrodynamic mixer was demonstrated by El Moctar et al. [8]. Here, an oil-oil two layer system was chosen where one oil phase was doped with an... 

Asahi Chemical, 9 676-677 Electrohydrodynamic-based heat exchangers, 13 269-270 Electrohydrodynamic (EHD) convection, in microfluidic mixers, 26 967 Electrokinetic flow... 

This micro mixer, named electrohydrodynamic (EHD) microfluidic mixer, comprises a simple T-channel structure (see Figure 1.5) [91]. After passing the T-junction, a bi-laminated stream is realized. Following a downstream zone for such flow establishment, a channel zone with several electrode wires on both sides of the channel is located. In this way, an electric field perpendicular to the fluid interface is generated. Thereafter, an electrode-free zone of the channel is situated for completion of the mixing initiated. 

This electrohydrodynamic (EHD) mixer (Figure 1.6) device provides a simple flowthrough chamber which has an upper and lower electrode for generating a electromagnetic field. The chamber channel is given by a sandwich of two plates, one being microstructured [94], The bottom plate contains a trapezoid channel. Two electrode layers are deposited on parts of the channel bottom and channel top and on the top part of this plate so that they reach the outside for external electrical contact. 

Figure 1.6 Schematic design of the electrohydrodYnamic (EHD) mixer (left) and cross-sectional view giving the electrode arrangement and sketching the flow motion induced by interfacial shear (right) [94] (by courtesy of Kluwer Academic Publishers).

When a voltage is applied across adjacent electrodes (in the pattern shown in Figure 12.1) at 1000 Hz, 250 VRMS, liquid droplets quickly center themselves over the inter-electrode gap. Electrohydrodynamic forces act as an efficient mixer in such a system. 

El Moctar AO, Aubry N, Batton J (2003) Electrohydrodynamic microfluidic mixer. Lab Chip 3(4) ... 

The term active mixer or active microimxef refers to a microfluidic device in which species mixing is enhanced by the application of some form of external energy disturbance. Typically, this disturbance is generated either by moving components within the micromixer itself, e.g. magnetically-actuated stirrers, or by the application of an external force field, e. g. pressure, ultrasound, acoustic, electrohydrodynamic, electrokinetic, dielectrophoretic, magneto-hydrodynamic, thermal, and so forth [1]. 

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