Deformation and initial breakup morphology of viscous emulsion drops in isotropic homogeneous turbulence with relevance for emulsification devices

https://doi.org/10.1016/j.ces.2022.117599Get rights and content
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Highlights

  • Breakup of viscous drops in HPH-similar conditions was studied with DNS.

  • Deformation is in a single (multiple) direction(s) for small (large) drops.

  • The lower the We, the more likely a drop is to enter an oscillatory phase.

  • The higher the We, the more likely a drop is to enter critical deformation/breakup.

  • Breakup occurs deterministically once a sufficiently thin neck has formed locally.

Abstract

This study uses numerical experiments to investigate initial breakup morphology for conditions similar to those experienced in an emulsification device (e.g., a high-pressure homogenizer) (Reλ = 33, We = 1–30, μDC = 22, ρDC = 0.9, D/η = 22). Results show breakup consisting of two phases: and ‘oscillatory phase’ where the drops are periodically deforming and relaxing, followed by a ‘critical deformation phase’ where the drop deforms continuously until initial breakup. Large drops (We ≥ 13) go directly to the breakup phase and are highly deformed in multiple direction before bursting. Smaller drops (3 ≤ We ≤ 5) are less likely to go directly to the critical deformation phase and more likely to never reach it before exiting the device. These drops break by the formation of a single filament, creating two large fragments and a number of smaller satellites. Several turbulent structures contribute to critical deformation.

Keywords

Emulsification
DNS
Drop breakup
Fragmentation
Turbulence
High-pressure homogenizer

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