Measurement of interfacial mass transfer of single bubbles rising in homogeneous turbulence.

• Idea of indirect quantification of interfacial mass transfer velocity k l of bubbles under high Reynolds number conditions. • SI-LIF measurement technique and reconstruction algorithm to attain physical quantities required to derive k l. • 3-D visualization and quantification of mass transfer of single bubbles rising in both quiescent water and homogeneous turbulence. • The measured k l are independent of R e T , and all collapse to the analytical solution of potential flow approximation. • Dominant effect of buoyancy of bubble instead of turbulent eddies on the interfacial mass transfer process is confirmed across the hydrodynamic conditions presented in this paper. Accurate quantification of the mass transfer coefficient k l of bubbles under high Reynolds number conditions has been in desperate need for decades to provide insights into its fundamental physics and reach a general mass transfer model. In this paper, a state-of-the-art SI-LIF technique is developed to quantify k l indirectly based on the law of conservation of mass. The reconstruction algorithms of the required physical quantities are validated numerically, suggesting an overall uncertainty of less than ± 5 % in the estimation of k l. We perform mass transfer experiments of single oxygen bubbles with d eq = 1.5 mm rising in both quiescent water and homogeneous turbulence, with turbulent Reynolds number R e T ranging from 0 to 1114. The measured k l under turbulent conditions are independent of R e T , and all collapse to the analytical solution of potential flow approximation, revealing that the flow in the immediate vicinity of the bubble interface remains undisturbed by the fluctuating liquid motions across all the turbulence settings examined in this paper. [ABSTRACT FROM AUTHOR]