Electrical current conduction and electrohydrodynamically induced fluid flow in an AW type EHD pump

An experimental investigation was conducted to study current conduction phenomena and electrohydrodynamic (EHD) induced flow for the air wave (AW) type EHD pump. An AW type EHD pump consists of a corona wire in gas phase and a grounded plate electrode inclined to gas–liquid interface, where mineral oil was used as the working fluid. Time-averaged discharge currents and corona discharge current waveforms in corona wire and plate electrodes under negative polarity were measured at the gas phase corona wire and at the liquid phase grounded plate to study current conduction phenomena. EHD induced liquid flow rate and liquid film thickness were measured as well as gas–liquid interfacial geometry. The results show that no significant electrical charge was carried by an EHD flow of oil beyond the pump sections and only slight current waveform difference was observed between corona discharge current and conduction current through the gas, gas–liquid interface and liquid phases. The effect of applied voltage is discussed in terms of dimensionless parameters in detail.