Electroosmotic Augmentation in Flexural Plate Wave Micropumps

We investigate the effectiveness and applicability of electroosmotic augmentation in flexural plate wave (FPW) micropumps for enhanced capabilities. Flow rates generated in FPW micro-scale flow systems are restricted particularly when the channel height is greater than the acoustic wave length. The proposed concept can be exploited to integrate micropumps into complex microfluidic chips improving the portability of micro-total-analysis systems along with the capabilities of actively controlling acoustics and electrokinetics for micro-mixer applications. A computational study of electroosmotic augmentation in FPW micropumps is presented where FPWs are considered by a moving wall model. A transient analysis of compressible flows of water is performed for microchannels. An isothermal equation of state for water is employed. The nonlinear Poisson-Boltzmann and Laplace equations are used to model the induced electric double layer (EDL) potential and the applied electric potential. Coupled electroosmotic and acoustics cases are investigated for two channel heights while the electric field intensity of the electrokinetic body forces and actuation frequency of acoustic excitations are varied. For deeper microchannels, increasing the actuation frequency of the wall motion does not improve the generated flow rate significantly. Inclusion of electroosmotic effects is more efficient than increasing the intensity of acoustic perturbations whenever high flow rates are required in micro-mixer applications.