| The use of electrohydrodynamic conduction micropumps in the cooling technology, drug delivery, and sensor applications is very limited in part because of the high voltage requirement necessary to drive the fluid, and as a result have not gained wide applications. This thesis presents theoretical and experimental study of the means of lowering the high voltage requirement and the dielectric behavior in the electric double layer. Different ratio of the dielectric permittivity over the viscosity is used to gain understanding of the impact of dielectric properties on the voltage applied with the flow rate. It was observed that the fluid flow rate was a function of the applied electric potential, the dielectric permittivity, and the fluid viscosity. Theoretical evidence showed the dielectric fluid volume flow rate was a function of applied voltage and the ratio of dielectric relative permittivity to viscosity. The theoretical analysis predicts that fluids with higher relative permittivity-viscosity ratio exhibit higher flow-rate compared to those for which this ratio is lower.;Three fluids were considered in this study namely: acetone (CH3-CO-CH3), methanol (CH3-OH), and ethyl alcohol (CH 3-CH2-OH) with relative permittivity-viscosity ratios of 68660.1, 56101.7, and 22191.8 respectively. Experimental results showed that the order of increasing flow-rates obtained were acetone, methanol, and ethyl-alcohol, thus verifying the result predicted by theory. Thus the applied electric potential to achieve a desired flow-rate can be lowered through a careful choice of dielectric fluid with high permittivity-viscosity ratio. |
