Drop Stream - Immiscible Jet Collisions: Regimes and Fragmentation Mechanisms

TL;DR

This study explores the collision dynamics between a continuous liquid jet and immiscible droplets, identifying four regimes and introducing a new 'drops in jet' regime with a model to predict transitions.

Contribution

It reports the first observation of the 'drops in jet' regime and develops a regime map based on dimensionless parameters for predicting collision outcomes.

Findings

Four collision regimes identified, including a novel 'drops in jet' regime.

A regime map distinguishes different outcomes based on derived parameters.

Model predicts transition boundaries between regimes.

Abstract

We investigate the collision of a continuous liquid jet with a regular stream of immiscible droplets. The immiscible liquids, namely silicon oil for the continuous jet and an aqueous glycerol solution for the drop stream, are selected to enable the total wetting of the drops by the jet liquid. Four different regimes are experimentally identified: drops in jet, encapsulation without satellites, encapsulation with satellites from the jet liquid and mixed fragmentation. The drops in jet regime, potentially of great interest for new applications, corresponds to a regular stream of drops embedded in a continuous jet and is described and reported for the first time. Using well known aspects of drop collision and jet stability, we propose to model the transition between the drops in jet regime and the others. Two dimensionless parameters are derived from this analysis which are thus used to produce a simple regime map where the drops in jet regime can be well distinguished from the other outcomes.