Effect of Surface Active Materials on Bubble Dynamics in Two-Phase Flow

Abstract

Our goal in this research is to relate bubble performance in processes such as bubble breaking, dissolution, coalescence and breakup to bubble interfacial character, including surface tension, surface charge and surface rheological properties. This fiscal year we have studied bubble dissolution rates in clean fresh water and in sea water samples representing a wide range of biological activities. Previous measurements of bubble dissolution have used water that was equilibrated with a known atmosphere a process that takes many hours and results in alteration of chemical and biological properties. We have used a novel gas tension method to determine 02 and N2 partial pressures in the water phase. Our results indicate that mass transfer rates for dissolution in fresh water coincide with theoretical predictions, but those for sea water are always significantly less and especially at low Reynolds Numbers. Bubble coalescence and breaking of bubbles at the air-water interface were observed in fresh water and sea water samples. Both process were observed to produce satellite bubbles. For example, millimeter-size bubbles breaking at the air-water interface each produced 20 or more bubbles of greater than 30 microns in diameter.... Bubble; Bubble Coalescence; Bubble Mass Transfer.

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Document Details

Document Type
Technical Report
Publication Date
Dec 23, 1992
Accession Number
ADA259340

Entities

People

  • Bruce D. Johnson

Organizations

  • Dalhousie University

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Artificial Satellites
  • Atmospheres
  • Boundary Layer
  • Coalescence
  • Dynamics
  • Films
  • Fresh Water
  • Gases
  • Mass Transfer
  • Materials
  • Measurement
  • Partial Pressure
  • Sea Water
  • Surface Tension
  • Thick Films
  • Water

Readers

  • Molecular Photonics/Laser Physics
  • Thin Film Deposition Science.
  • Underwater engineering and Marine Technology.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster