Density effects in interfacial convection

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Abstract

Experimental evidence is presented showing that density gradients developed during the transfer of a solute across a liquid—liquid interface exert a strong influence on convection generated by interfacial tension variations. Stabilizing density gradients confine interfacial convection to narrow zones adjacent to the interface while de-stabilizing gradients generate eddies streaming away from the interface and penetrating deeply into the bulk phases.

Résumé

On présente des données d'expériences démontrant que les pentes de densité produites au cours du transfert d'un soluté à travers une interface liquide—liquide exercent une influence importante sur la convection générée par les variations de tension à l'interface. Des pentes de densité stabilisantes limitent la convection interfaciale à des zones étroites à côté de l'interface, tandis que les pentes de déstabilisation produisent un courant turbulent ayant sont origine à l'interface et pénétrant profondément dans les phases massives.

Zusammenfassung

Es wird experimentell der Beweis erbracht, dass die während des Überganges eines aufgelösten Stoffes durch eine flüssig—flüssig Grenzschicht entwickelten Dichtegradienten einen beträchtlichen Einfluss auf die durch Spannunggsänderungen in der Grenzschicht hervorgerufene Konvektion ausüben. Stabilisierende Dichtegefälle begrenzen die Konvektion in der Grenzschicht auf schmale, der Zwischenschicht benachbarte Zonen, während entstabilisierende Gefälle Wirbel erzeugen, die von der Zwischenschicht wegströmen und tief in die Hauptphasen eindringen.

References (42)

  • L.J. Austin et al.

    Chem. Engng Sci.

    (1966)
  • C.A.P. Bakker et al.

    Chem. Engng Sci.

    (1966)
  • C.A.P. Bakker et al.

    Chem. Engng Sci.

    (1967)
  • P.V. Danckwerts et al.

    Chem. Engng Sci.

    (1967)
  • J.B. Lewis

    Chem. Engng Sci.

    (1954)
  • H. Linde et al.

    Z. phys. Chem.

    (1966)
  • E. Ruckenstein

    Chem. Engng Sci.

    (1964)
  • K. Sigwart et al.

    Naturwissenschaften

    (1955)
  • K. Sigwart et al.

    Z. Ver. dt. Ing.

    (1956)
  • R.C. Reid et al.
  • J.C. Berg et al.

    J. Fluid Mech.

    (1966)
  • J.C. Berg et al.

    Trend in Engng

    (1965)
  • P.L.T. Brian et al.

    A.I.Ch.E.Jl

    (1967)
  • R. Bruckner

    Naturwissenschaften

    (1960)
  • J.T. Davies

    Trans. Instn chem. Engrs

    (1960)
  • S.R.M. Ellis et al.

    Chem. Engng Sci.

    (1967)
  • D.A. Haydon

    Proc. R. Soc.

    (1958)
  • S. Hoshino et al.

    Kagaku Kogaku

    (1966)
  • H. Kroepelin et al.

    Naturwissenschaften

    (1956)
  • J.B. Lewis et al.

    Nature, Lond.

    (1953)
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    Present Address: Fairchild Semi-Conductor Co., Mountainview, California, U.S.A.

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