Electrical charge transport and energy conversion with fluid flow during electrohydrodynamic conduction pumping

The electrohydrodynamic (EHD) conduction pumping takes advantage of the electrical Coulomb force exerted on dielectric liquid by externally applied electric field(s). The conduction term here represents a mechanism for electric current flow in which charged carriers are produced not by injection from electrodes or induction from electric fields, but by dissociation of neutral electrolytic species within the dielectric liquid. The EHD conduction pumping can be applied to drive both isothermal liquid and two-phase fluids without the degradation of the working fluid electric properties. Such nonmechanical and low-power-consumption pumping mechanism can be utilized for active flow generation/control under both terrestrial and microgravity conditions. So far, the majority of conducted studies has been focused mainly on the experimental realization of the EHD conduction pumping phenomenon and the computational fluid dynamics simulation verification. More fundamental studies, such as theoretical analysis with convection terms included, generalized nondimensional modeling, and pumping efficiency prediction, are required for a complete understanding of this new EHD pumping phenomenon. An asymptotic nondimensional theoretical model for the EHD conduction pumping has been presented in this paper, with the fluid convection taken into account. The theoretical analysis provided here reveals the effects of flow convection on the EHD conduction pumping and the associated energy transport/conversion during the pumping process. Based on the asymptotic model, the pumping efficiency of the EHD conduction pumping is analytically derived and compared with the experimental data. Such results help clarify the capabilities and limitations corresponding to the nature of the EHD conduction pumping. (C) 2007 American Institute of Physics.