Formation and droplet size of EHD drippings induced by superimposing an electric pulse to background voltage

The effect of electric voltages on droplet size was investigated. Results show that both background voltage and amplitude of electric pulse could affect the process of droplet formation and droplet size while the width of pulsed voltage had a slight effect on droplet size. Pulsed voltages introduced a tangential electric stress that led to relatively greater droplet formation while greater background voltage was associated with smaller droplets. Due to different components of the normal and tangential electric stress three dripping modes were created. Based on above observations, a simplified discussion is presented on the relationships between droplet size and above parameters.