On the migration of a single gas bubble in water

Resumo

A theoretical model of a single gas bubble rising in open water is considered. It is revealed that methane bubble rising is accompanied by the formation of the hydration shell on its surface under the thermobaric conditions of the stability of hydrates. Numerical solutions for two limiting cases were obtained and analyzed, when the formation rate of the hydrated crust on the bubble surface is limited by the intensity of heat removal released in the process of hydrate formation by the surrounding liquid or the diffusion resistance of the gas hydrate crust to the transfer of hydrate-forming components. The comparison of numerical results with experimental data showed that the scheme of the diffusion transfer of hydrate-forming components through the crust describes most adequately the process of the growth of the gas hydrate particle observed in experiments of methane bubbles rising in sea water. It is established that argon bubble rising under the corresponding thermobaric conditions can occur without the formation of the hydrate on its surface. The migration of the gas bubble is accompanied by its dissolution in water. Numerical estimates for the values of the argon diffusion coefficient in water and reduced diffusion coefficients of gas (methane) and water through the hydrate crust are obtained from the conditions of matching theoretical and experimental data from the change of the argon bubble radius and the gas hydrate particle.