International Journal of Heat and Mass Transfer, Vol.135, 1248-1259, 2019
Direct numerical simulation of the interfacial mass transfer of a bubble in self-induced turbulent flows
Bubbly flows and the interfacial mass transfer of bubbles are important processes in chemical engineering. The mass transfer rate of bubbles is usually approximated by using a correlation of the Sherwood number since the direct simulation or measurement of the behavior for each bubble is too expensive for industrial applications. However, the effect of turbulence induced by the bubble swarm on bubble's mass transfer is very complicated and its impact on the Sherwood number is still not clear. As the first step of understanding the effect of swarm turbulence, we have simulated the interfacial mass transfer of a bubble in self-induced turbulence using a direct numerical simulation (DNS) method. The gas phase is accounted for using a volume of fluid method. The effects of bubble Reynolds number, Schmidt number, bubble's volume fraction, and Eatvos number on the flow and species concentration fields have been studied. The Reynolds numbers in the range 100-400, the Schmidt numbers in the range 1-4 are under consideration. Based on our DNS results, a correlation for the Sherwood number has been proposed. The effect of the bubble's volume fraction and the Eatvos number can be accounted for in the proposed correlation. We expect that the general form of the correlation can be used for real bubble swarms, however, the model coefficients should be determined from the experimental/DNS data obtained under the real conditions. (C) 2019 Elsevier Ltd. All rights reserved.