The coalescence of two drops in presence of electric field occurs in three stages; (a) electrostatic attraction of two drops, (b) drainage of interstitial film between drops, and (c) breakup of thin film and merging of drops. The present work addresses the interaction of a pair of drops in a uniform DC electric field. The primary focus of this study is on the drop approach and the film drainage stages of electrocoalescence. Electrocoalescence in two fluid systems; perfectly conducting drops in perfectly dielectric medium (PC-PD) and leaky dielectric drops in leaky dielectric medium (LD-LD) is studied experimentally (using high speed videography), numerically (using the boundary element method) and the results are compared with existing analytical theories. In the present work we have looked at some of the un-addressed issues in the electrocoalescence literature. Specifically we believe this is the first study in electrocoalescence with a direct comparison of numerical and experimental results in PC-PD fluid system that highlights the role of film approach and film drainage steps. Also, this is possibly the first experimental study in LD-LD fluid systems that presents a comparison of experimental results with numerical and analytical theory.
