Theoretical and Experimental Investigation of Film Drainage Time

In many industrial process units for dispersed liquid-liquid and gas-liquid flows, understanding of the fluid particle breakup and coalescence phenomena are important for optimal process operation. These phenomena do not only dominate the fluid particle size distributions, but also directly affect the mass, momentum and heat transfer through the renewal surface and thus the contact area. This work focuses on the coalescence process between two fluid particles; in particular the coalescence (film drainage) time which appears in some closures used to close the coalescence terms of the population balance equation (PBE). The coalescence time of different drop-drop and liquid-liquid systems were investigated experimentally by micromanipulator technique. Further, the derivation of the coalescence time model used in the popular coalescence closure by Prince and Blanch [1] has been analyzed. The results show significant deviation between the model prediction and experimental data of coalescence time.