Bubble Separation in a Gas–Liquid Swirling Pipe Flow

Abstract

Gas–liquid swirling pipe flow plays an essential role in phase separators. Bubble motions and flow patterns transitions in the flow are crucial for further investigation of this flow. However, much attention has been paid to these in non-swirl flow instead of swirl flow. In this work, bubble separation generated by a vane-typed swirler in a vertical pipe with an inner diameter of 62 mm was experimentally studied. Superficial air velocities (0.036 − 1.41 m/s) and superficial water velocities (0.02 − 0.95 m/s). The results show that dispersed bubbles gradually transform to gas column flow with increasing superficial water velocities (0.093 − 0.640 m/s) in the swirl flow; gas column flow gradually transforms to swirling intermittent flow with increasing superficial air velocities (0.05 − 0.40 m/s), and one peak increases to two peaks in the probability density function curve of pressure drop; slug flow can transform to swirling intermittent flow. Finally, transition criteria for bubble separation were proposed: when the turbulent fluctuations are strong enough to overcome centrifugal force, then the bubbles move to the pipe center and coalescence with each other, lead to the transition of gas column flow/swirling intermittent flow.

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

This work was supported by the Guangdong Basic and Applied Basic Research Foundation under Grant (number 2022A1515140070, 2023A1515140073); Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences under Grant (number E229kf17); and Scientific Research Project of Education Department of Guangdong Province under Grant (number 2022KCXTD029).

Notes on contributors

Wen Liu

Wen Liu has worked at Foshan University since 2022. She obtained her Ph.D. in power engineering and engineering thermophysics at the State Key Laboratory of Multiphase Flow at Xi’an Jiaotong University, China in 2016. From 2019 to 2020, she worked at the Department of Mechanical Engineering in the Johns Hopkins University as a visiting scholar with Prof. Gretar Tryggvason. Her current research focuses on experiments and modeling for multiphase flow, swirling flow, separation, and their engineering applications. She has published more than 30 papers in journals and conferences.

Pingnan Huang

Pingnan Huang has worked at Foshan University since 2022. He obtained his Ph.D. in Mechanical Engineering at the school of mechanical and automotive engineering at South China University of Technology, China in 2022. His current research focuses on heat transfer enhancement, topology optimization of microchannel heat sink and vapor chamber. He has published more than 10 papers in journals.

Nan Wu

Nan Wu has worked at Foshan University since 2021. She obtained her Ph.D. in power engineering and engineering thermophysics at the University of Science and Technology of China in 2019. From 2019 to 2021 she worked at Shenzhen University as a postdoctoral. Her current research focuses on battery thermal management in new energy vehicles and active thermal protection techniques. She has published more than 15 papers in journals and conferences.