Single drop breakage in turbulent flow: Statistical data analysis

Eirik H Herø,Nicolas La Forgia,Jannike Solsvik,Hugo A Jakobsen

doi:10.1016/j.cesx.2020.100082

Eirik H Herø, Nicolas La Forgia + Show 2 more

Open Access

https://doi.org/10.1016/j.cesx.2020.100082

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Abstract

To improve breakage models in the population balance framework, single octanol droplet experiments have been performed in a channel flow and recorded by high-speed camera. The study investigates impact of mother drop size on the breakage time, breakage probability, average number of daughters and the daughter size distribution for known turbulence characteristics. Each breakage event is associated with an individual turbulence level, based on the local flow characteristics. A clearly defined statistical analysis is presented. Using 95% confidence intervals, the precision of each of the determined properties is described quantitatively. Furthermore, the confidence intervals are a tool for determining whether an increased number of experiments will yield a significant increase in the precision, considered against the sources of error. It is found that 35–50 breakage events are sufficient to obtain confidence intervals of desired precision.

Highlights

The dispersed phase properties in multiphase flows are of interest for several fields of industry
The droplets were inserted into a channel flow and the following breakage events were captured by high speed cameras
The design of the channel allows for breakage events to occur in a turbulent flow with low gradients

Summary

Introduction

The dispersed phase properties in multiphase flows are of interest for several fields of industry. Some examples of industrial applications of low turbulence level flows are channel or pipe flow, bioand chemical-reactor flows, as well as phase separation equipment like gravity separators. The transient breakage phenomenon must be well understood for predictive simulation of such systems. The knowledge of the turbulent breakage phenomenon is scarce, likely owing to technological limitations and labor intensive experimental procedures. One simulation tool available for multiphase flow systems is the population balance equation, PBE. There is a need for experiments on single fluid particle breakage in order to improve or validate breakage models within this framework. This need has previously been acknowledged by e.g. Which is found through investigating: – The breakage time tBðDmÞ, which is the time it takes for a drop of size Dm to break

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