Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles

doi:10.1016/j.cjche.2023.06.010

中国化学工程学报 ›› 2024, Vol. 65 ›› Issue (1): 63-74.DOI: 10.1016/j.cjche.2023.06.010

• Full Length Article • 上一篇下一篇

Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles

Yuan Yao¹, Peiqiao Liu¹, Qian Zhang¹, Zequan Li¹, Benjun Xi², Changyuan Tao¹, Yundong Wang³, Zuohua Liu¹

1 School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
2 Hubei Three Gorges Laboratory, Yichang 443007, China;
3 Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

收稿日期:2023-04-18 修回日期:2023-06-26 出版日期:2024-01-28 发布日期:2024-04-17
通讯作者: Zuohua Liu,E-mail:liuzuohua@cqu.edu.cn
基金资助:
This work was supported by the National Key Research and Development Project (2022YFB3504305, 2019YFC1905802), National Natural Science Foundation of China (22078030), Joint Funds of the National Natural Science Foundation of China (U1802255), Key Project of Independent Research Project of State Key Laboratory of Coal Mine Disaster Dynamics and Control (2011DA105287-zd201902), Three Gorges Laboratory Open Fund of Hubei Province (SK211009, SK215001).

Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles

Yuan Yao¹, Peiqiao Liu¹, Qian Zhang¹, Zequan Li¹, Benjun Xi², Changyuan Tao¹, Yundong Wang³, Zuohua Liu¹

1 School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
2 Hubei Three Gorges Laboratory, Yichang 443007, China;
3 Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

Received:2023-04-18 Revised:2023-06-26 Online:2024-01-28 Published:2024-04-17
Contact: Zuohua Liu,E-mail:liuzuohua@cqu.edu.cn
Supported by:
This work was supported by the National Key Research and Development Project (2022YFB3504305, 2019YFC1905802), National Natural Science Foundation of China (22078030), Joint Funds of the National Natural Science Foundation of China (U1802255), Key Project of Independent Research Project of State Key Laboratory of Coal Mine Disaster Dynamics and Control (2011DA105287-zd201902), Three Gorges Laboratory Open Fund of Hubei Province (SK211009, SK215001).

摘要/Abstract

摘要： Elliptical tanks were used as an alternative to circular tanks in order to improve mixing efficiency and reduce mixing time in unbaffled stirred tanks (USTs). Five different aspect ratios of elliptical vessels were designed to compare their mixing time and flow field. Computational fluid dynamics (CFD) simulations were performed using the k-ε model to calculate the mixing time and simulate turbulent flow field features, such as streamline shape, velocity distribution, vortex core region distribution, and turbulent kinetic energy (TKE) transfer. Visualization was also carried out to track the tinctorial evolution of the liquid phase. Results reveal that elliptical stirred tanks can significantly improve mixing performance in USTs. Specifically, the mixing time at an aspect ratio of 2.00 is only 45.3% of the one of a circular stirred tank. Furthermore, the secondary flow is strengthened and the vortex core region increases with the increase of aspect ratio. The axial velocity is more sensitive to the aspect ratio than the circumferential and radial velocity. Additionally, the TKE transfer in elliptical vessels is altered. These findings suggest that elliptical vessels offer a promising alternative to circular vessels for enhancing mixing performance in USTs.

关键词: Mixing time, CFD, Stirred tank, Secondary flow, Mixing performance

Abstract: Elliptical tanks were used as an alternative to circular tanks in order to improve mixing efficiency and reduce mixing time in unbaffled stirred tanks (USTs). Five different aspect ratios of elliptical vessels were designed to compare their mixing time and flow field. Computational fluid dynamics (CFD) simulations were performed using the k-ε model to calculate the mixing time and simulate turbulent flow field features, such as streamline shape, velocity distribution, vortex core region distribution, and turbulent kinetic energy (TKE) transfer. Visualization was also carried out to track the tinctorial evolution of the liquid phase. Results reveal that elliptical stirred tanks can significantly improve mixing performance in USTs. Specifically, the mixing time at an aspect ratio of 2.00 is only 45.3% of the one of a circular stirred tank. Furthermore, the secondary flow is strengthened and the vortex core region increases with the increase of aspect ratio. The axial velocity is more sensitive to the aspect ratio than the circumferential and radial velocity. Additionally, the TKE transfer in elliptical vessels is altered. These findings suggest that elliptical vessels offer a promising alternative to circular vessels for enhancing mixing performance in USTs.

Key words: Mixing time, CFD, Stirred tank, Secondary flow, Mixing performance

Yuan Yao, Peiqiao Liu, Qian Zhang, Zequan Li, Benjun Xi, Changyuan Tao, Yundong Wang, Zuohua Liu. Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles[J]. 中国化学工程学报, 2024, 65(1): 63-74.

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Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles

Effect of aspect ratio of elliptical stirred vessel on mixing time and flow field characteristics in the absence of baffles

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