Numerical simulation on the terminal rise velocity and mass transfer rate of single sub-millimeter bubbles. (31st December 2021)

• Record Type: Journal Article
• Authors: Li, Chengxiang; Cui, Yizhou; Shi, Xiaogang; Gao, Jinsen; Lan, Xingying
• Is Part Of: Chemical engineering science. Volume 246(2021)
• Publication Date: 2021-12-31
• Subjects: Sub-millimeter bubbles -- Mass transfer -- Bubble terminal rise velocity -- Computational fluid dynamics; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2021.116963
• Languages: English
• ISSNs: 0009-2509

Abstract

Graphical abstract: Highlights: The terminal rise velocity and the liquid-side mass transfer coefficient of single sub-millimeter bubbles are obtained through numerical simulation. Accuracy of the simulation is verified by comparison with literature equations and experimental data. The literature equations are valid in a limited range and cannot predict the behavior of sub-millimeter bubbles over the whole size range. New equations are proposed for calculating the terminal rise velocity and the liquid-side mass transfer coefficient of sub-millimeter bubbles. The reason why the liquid-side mass transfer coefficient of small fully contaminated bubbles keeps roughly constant is discussed. Abstract: Gas–liquid reactors containing bubbles are intensively used in the chemical industry. However, the gas–liquid mass transfer is usually the rate-limiting step. One possible way to intensify the mass transfer is the application of sub-millimeter bubbles (1–1000 μm) which efficiently increase interfacial area. Literature usually focused on bubbles larger than 1000 μm, and it still needs to be studied whether the frequently-used literature equations for terminal rise velocity and mass transfer can accurately predict the behavior of sub-millimeter bubbles. Therefore, the terminal rise velocity and mass transfer rate of single sub-millimeter bubbles were obtained by numerical simulation. It was found that the literature equations could not accurately predict the behavior of sub-millimeter bubbles over the whole size range. New equations were proposed to improve calculation accuracy, with which the terminal rise velocity and mass transfer rate of sub-millimeter bubbles can be accurately predicted.