Flow pattern visualization of liquid film conduction pumping using flush mounted electrodes

摘要

Conduction pumping is one convenient method for pumping of dielectric liquid films. Flow visualization can be useful for understanding the hydrodynamic behavior of this kind of flow. In this study, the flow pattern of the liquid film conduction pumping using flush mounted electrodes has been visualized for various electrode arrangements. Symmetric and asymmetric configurations of electrodes have been examined for pumping of silicon oil. Two major factors affect the conduction pumps; ion mobility difference and electrodes configuration. For known ion mobility difference two cases have been considered: Case 1 in which electrode configuration strengthens the ion mobility difference pumping effect and Case2 in which electrode configuration has the opposite effect. The results show that, for one pair of electrodes acting as unit pump, a primary vortex is generated on the electrodes which arises from rotational part of the Coulomb force. For more than one pair of electrodes, secondary vortices appeared which are generated by the primary vortices. For Case 1, the vorticity of primary and secondary vortices increases with electrode width ratio because of the strengthening effect of the two factors but it decreases for Case 2 because of weakening effect of them.