The Onset of Fragmentation in Ternary Drop Collisions

TL;DR

This study investigates the stability and outcomes of ternary drop collisions, revealing similarities and differences with binary collisions, which is crucial for applications in micro-reactors and particle synthesis.

Contribution

It provides the first experimental analysis of ternary drop collisions, establishing a regime map and comparing outcomes to binary collisions.

Findings

Identified coalescence, bouncing, and separation regimes in ternary collisions.

Compared transition boundaries with binary collision regimes.

Observed differences in regime transition behaviors.

Abstract

Recently it has been proposed to use colliding drops for producing advanced particles or well defined capsules, or to perform chemical reactions where the merged drops constitute a micro-reactor. For all these promising applications it is essential to determine whether the merged drops remain stable after the collision, forming a single entity, or if they break up. This topic, widely investigated for binary drop collisions of miscible and immiscible liquids, is quite unexplored for ternary drop collisions. The current study aims to close this gap by experimentally investigating collisions of three equal-sized drops of the same liquid, arranged centri-symmetrically. To do this, three drop generators are simultaneously operated to obtain controlled ternary drop collisions. The collision outcomes are observed on photographs and compared to those of binary collisions. Similar to binary collisions, a regime map is built, showing coalescence and bouncing as well as reflexive and stretching separation. Differences are observed in the transitions between these regimes.