Growth and detachment of carbon dioxide bubbles on a horizontal porous surface with a uniform mass injection

摘要

Growth and detachment of carbon dioxide bubbles on a horizontal porous surface in water is investigated in this paper. Uniform carbon dioxide injection on the porous surface is considered. The Young-Laplace equation is solved with the geometry method to yield the bubble shape. The dynamic pressure on the bubble surface due to bubble expansion is neglected. Multi-solution modes are found. Based on the characteristics of the solution modes, it is postulated that the bubble grows with a monotonicaliy increasing base area until the maximum value is reached according to the fundamental solution mode. After that, the bubble jumps toward the secondary solution mode at a constant volume, and then detaches from the surface. The increasing rate of the bubble volume due to mass diffusion/convection is evaluated by solving the momentum and concentration equations. Evolution of the bubble shape then is determined corresponding to the variation of the bubble volume. The numerical results indicate that hydrophobic surface produces large bubble and thus gives rise to better efficiency for dissolved gas removal.