Recent developments of turbulent emulsions in Taylor-Couette flow

TL;DR

This review paper discusses recent advances in understanding turbulent emulsions within Taylor-Couette flow, focusing on droplet dynamics, global momentum transport, and phase inversion phenomena, highlighting key experimental and theoretical findings.

Contribution

It provides a comprehensive overview of recent experimental and theoretical studies on turbulent emulsions in Taylor-Couette flow, emphasizing droplet statistics and phase inversion mechanisms.

Findings

Droplet size distribution and breakup mechanisms in dilute emulsions.

Relationship between droplet statistics and effective viscosity in dense emulsions.

Conditions leading to catastrophic phase inversions during emulsification.

Abstract

Emulsions are common in many natural and industrial settings. Recently, much attention has been put on understanding the dynamics of turbulent emulsions. This paper reviews some recent studies of emulsions in turbulent Taylor-Couette flow, mainly focusing on the statistics of the dispersed phase and the global momentum transport of the system. We first study the size distribution and the breakup mechanism of the dispersed droplets for turbulent emulsions with a low volume-fraction (dilute) of the dispersed phase. For systems with a high volume-fraction of the dispersed phase (dense), we address the detailed response of the global transport (effective viscosity) of the turbulent emulsion and its connection to the droplet statistics. Finally, we will discuss catastrophic phase inversions, which can happen when the volume fraction of the dispersed phase exceeds a critical value during dynamic emulsification. We end the manuscript with a summary and an outlook including some open questions for future research. This article is part of the theme issue `Taylor-Couette and Related Flows on the Centennial of Taylor's Seminal Philosophical Transactions Paper'.