Experimental Investigations of Interfacial and Binary Coalescence of Multilayered Drops

In the present work, experimental investigations of interfacial and binary coalescence of multilayered drops are performed in a small channel for the kerosene-water system. The mechanistic differences between the interfacial coalescence of a single isolated drop, single-layered and multilayered drops are analyzed in detail. The effects of the drop size, interfacial tension, and continuous-phase viscosity on the frequencies of interfacial and binary coalescence are investigated. Because of the influence of the surrounding drops, the interfacial coalescence frequency is found to be significantly higher in the case of multilayered drops. On the basis of the measured data, an empirical correlation is developed to predict the interfacial coalescence frequency. These measurements provide the crucial database required to develop kernels for the interfacial and binary coalescence rates. Such kernels are important to predict the drop size distribution using population balance or integrated CFD+PBM models.