Study on the distribution of critical liquid bridge length in droplet formation under dripping regime in an annular shear flow field

Abstract

A simplified experimental device was used to simulate the annular shear flow field in a liquid–liquid cyclone reactor, and the formation and break up behaviour of the liquid bridge during the droplet formation under the dripping regime was investigated. Deionized water and fluorescent oil were used as continuous phase and dispersed phase, respectively. The formation and break up process of dispersed phase liquid bridge in the annular simplified experimental device in the dripping regime was captured by camera. The impacts of the ratio of continuous phase velocity to dispersed phase velocity (Vr) and the capillary number (Ca) on the mean critical liquid bridge length (MBL) were analyzed. Furthermore, the functional relationships between MBL and operating parameters (Vr and Ca) under the dripping regime were obtained. The results indicate that the process of droplet formation is mainly affected by viscous force, shear force and surface tension. MBL increases firstly and then decreases with the increase of the two-phase velocity ratio in dripping regime. Additionally, with the increase of capillary number, MBL decreases.