Dissolution of a CO2 spherical cap bubble adhered to a flat surface in air-saturated water Articles uri icon

authors

  • PEÑAS LOPEZ, PABLO
  • PARRALES BORRERO, MIGUEL ANGEL
  • RODRIGUEZ RODRIGUEZ, JAVIER

publication date

  • July 2015

start page

  • 53

end page

  • 76

volume

  • 775

international standard serial number (ISSN)

  • 0022-1120

electronic international standard serial number (EISSN)

  • 1469-7645

abstract

  • Bubbles adhered to partially hydrophobic flat surfaces often attain a spherical cap shape with a contact angle much greater than zero. We address the fundamental problem of the diffusion-driven dissolution of a sessile spherical cap bubble (SCB) adhered to a flat smooth surface. In particular, we perform experiments on the dissolution of CO2 bubbles (with initial radii similar to 1 mm) immersed in air-saturated water adhered to two substrates with different levels of hydrophobicity. It is found that the contact angle dynamics plays an important role in the bubble dissolution rate. A dissolution model for a multicomponent SCB in an isothermal and uniform pressure environment is then devised. The model is based on the quasi-stationary approximation. It includes the effect of the contact angle dynamics, whose behaviour is predicted by means of a simplified model based on the results obtained from adhesion hysteresis. The presence of an impermeable substrate hinders the overall rate of mass transfer. Two approaches are considered in its determination: (a) the inclusion of a diffusion boundary layer-plate interaction model and (b) a finite-difference solution. The model solutions are compared with the experimental results, yielding fairly good agreement.

keywords

  • Bubble dynamics
    Contact angle dynamics
    Contact lines