Mass Transfer of Gas Bubbles Rising in Stagnant Water

This paper presents an analytical study of mass transfer from a single bubble rising in stagnant water and its size variation. A model for bubble-water mass transfer was established and validated using the experimental measurements from a rising carbon dioxide bubble. The effects of bubble horizontal velocity, bubble release depth, initial bubble size, background dissolved gas concentration in the water, and bubble swarms on the bubble-water mass transfer were examined. The bubble size changed along the rising path in response to both the mass transfer and the local hydrostatic pressure, whereas their relative importance varied under different conditions. Compared with previous models, the proposed model improved the prediction accuracy by including the influence of changing dissolved gas concentration in the water and mass transfer across the water surface. The model is applicable for different gases and can be used in a wide range of engineering applications.