Rising characteristics of a methane bubble under different conditions: A CFD study

Abstract

For a methane (CH4) bubble rising in liquid, knowledge of bubble rising characteristics is crucial for the comprehension of methane dissolution rate and the inter-phase mass transfer. Here, the investigation of a methane bubble was performed using the computational fluid dynamics (CFD) technique and the volume of fluid (VOF) two-phase model. The deionized water of 13 MPa and 5°C was used as the carrier of the rising bubble. Bubbles with diameters ranging from 3.0-6.0 mm were selected. The results show that the bubble instantaneous liquid velocity distribution and the wake structure manifest unique characteristics under such a high-pressure and low-temperature condition. The bubbly flow involves complicated vortex structures. Moreover, the bubble velocity is relatively low relative to those obtained under general conditions. A non-dimensional analysis of the bubble behavior indicates that the results obtained here deviate significantly from available results obtained under general conditions. The bubble diameter significantly influences the drag coefficient.