Two-dimensional modeling of a novel micro-pump based on an induced-charge electro-osmotic phenomenon

In the present study, a two-dimensional (2D) low Reynolds number continuous liquid flow in a novel direct current-powered induced-charge electro-osmotic (ICEO) micro-pump, containing an array of five electrically conducting obstacles and four micro-electrodes, embedded on the micro-pump's walls, was numerically investigated, using the finite volume method. The effects of different parameters, including the geometry of the obstacles (triangle, airfoil shape, kite shape, rhombus, and ellipse), the intensity of the externally applied electric field, and its direction, third dimension, and fabrication defects, were studied. Moreover, novel obstacles in shape of a horizontal tooth were introduced for ICEO flow pumping and effects of their aspect ratio and fabrication defects were investigated. Based on the results, the fore-aft symmetric obstacles, i.e., ellipse and rhombus, are not suitable for pumping. As an important conclusion, the tooth-shaped obstacles outperform all other geometries, achieving the highest outlet velocity and volumetric flow rate. Moreover, a 2D simulation overestimates the micro-pump's performance due to not considering the walls friction. Additionally, the micro-pumps performance is highly sensitive to fabrication accuracy of obstacles. However, increasing the intensity of the external electric field causes an increase in flow rate, average outlet velocity, and Reynolds number of all cases studied. On the other hand, the flow direction generated by conducting obstacles is independent of the horizontal electric field direction. Furthermore, the pumping improvement resulting from changing geometry of the obstacles does not change with increasing the electric field intensity.