Cristin-resultat-ID: 1492772
Sist endret: 4. juli 2018, 15:51
NVI-rapporteringsår: 2017
Resultat
Vitenskapelig artikkel
2017

Influence of surfactants on the electrohydrodynamic stretching of water drops in oil

Bidragsytere:
  • Åsmund Ervik
  • Torstein Eidsnes Penne
  • Svein Magne Hellesø
  • Svend Tollak Munkejord og
  • Bernhard Müller

Tidsskrift

International Journal of Multiphase Flow
ISSN 0301-9322
e-ISSN 1879-3533
NVI-nivå 1

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2017
Publisert online: 2017
Trykket: 2018
Volum: 98
Sider: 96 - 109
Open Access

Importkilder

Scopus-ID: 2-s2.0-85033699761

Beskrivelse Beskrivelse

Tittel

Influence of surfactants on the electrohydrodynamic stretching of water drops in oil

Sammendrag

In this paper we present experimental and numerical studies of the electrohydrodynamic stretching of a sub-millimetre-sized salt water drop, immersed in oil with added non-ionic surfactant, and subjected to a suddenly applied electric field of magnitude approaching 1 kV/mm. By varying the drop size, electric field strength and surfactant concentration we cover the whole range of electric capillary numbers (CaE) from 0 up to the limit of drop disintegration. The results are compared with the analytical result by G.I. Taylor (Proc. R. Soc. A280, 383 (1964)) which predicts the asymptotic deformation as a function of CaE. We find that the addition of surfactant damps the transient oscillations and that the drops may be stretched slightly beyond the stability limit found by Taylor. We proceed to study the damping of the oscillations, and show that increasing the surfactant concentration has a dual effect of first increasing the damping at low concentrations, and then increasing the asymptotic deformation at higher concentrations. We explain this by comparing the Marangoni forces and the interfacial tension as the drops deform. Finally, we have observed in the experiments a significant hysteresis effect when drops in oil with large concentration of surfactant are subjected to repeated deformations with increasing electric field strengths. This effect is not attributable to the flow nor the interfacial surfactant transport. © 2017 Elsevier Ltd. All rights reserved.

Bidragsytere

Åsmund Ervik

  • Tilknyttet:
    Forfatter
    ved Gassteknologi ved SINTEF Energi AS
  • Tilknyttet:
    Forfatter
    ved Institutt for energi- og prosessteknikk ved Norges teknisk-naturvitenskapelige universitet

Torstein Eidsnes Penne

  • Tilknyttet:
    Forfatter
    ved Institutt for fysikk ved Norges teknisk-naturvitenskapelige universitet

Svein Magne Hellesø

  • Tilknyttet:
    Forfatter
    ved Elkraftteknologi ved SINTEF Energi AS

Svend Tollak Munkejord

  • Tilknyttet:
    Forfatter
    ved Gassteknologi ved SINTEF Energi AS

Bernhard Müller

  • Tilknyttet:
    Forfatter
    ved Institutt for energi- og prosessteknikk ved Norges teknisk-naturvitenskapelige universitet
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