Experimental Study on EHD Effects on Wetting Characteristics of Liquid in Open Rectangular Microgrooves

Abstract Liquid wetting characteristics under EHD (Electrohydrodynamic) effects as a function of heat flux, voltages, microgroove inclination and dimensions in open rectangular microgrooves have been experimentally investigated. Two planar electrodes were used to generate electric fields. Wetting length was captured by a camera and it was determined according to the locations of marking lines that were measured by a caliper. The uncertainties of the heat loss and wetting length are 11.11% and 7.46%, respectively. Results indicate that higher heat flux can be achieved by electric fields effects. Wetting length increases notably by EHD pumping at a lower inclination. It is observed that microgrooves with smaller depth/width ratio perform a more pronounced increase of wetting length in the presence of electric fields. In addition, theoretical analyses show that the wetting length under electric field effects increases with the increasing groove depth while decreases as the groove width increases. Besides, both the threshold and optimal voltage are smaller for microgrooves with larger depth/width ratio. Moreover, the threshold voltage decreases with the increase of the depth/width ratio linearly. The findings are useful for the design of the EHD augmented grooved microfluidic devices with considering the fair geometrical dimensions and electric field voltages.