Critical Falling Heights for the First Break-up of Liquid Drops Impacting on Immiscible Liquids

Abstract

Experimental studies investigating the break-up of liquid drops impacting on immiscible target liquids have been undertaken. The critical falling height at which the first break-up occurs has been found to be proportional to the drop mass to the power of –0.65±0.05, irrespective of change in physical properties of either drop or target liquid, and can be related to the drop mass by the following equation:

H_cr=k_cWⁿ

where H_cr is the critical falling height, k_c is the proportionality constant, W is the mass of liquid drop, and n is the power (–0.65±0.05). The value of k_c varies with change in physical properties of drop or target liquid, and hence the critical falling height is dependent on the physical properties of both drop and target liquids. The mechanism of the first break-up changes from the cavity-pulled to the rebounding-jet break-up as the viscosity of either the drop or target liquid increases.