Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

doi:10.1016/j.cjche.2022.06.001

Chinese Journal of Chemical Engineering ›› 2023, Vol. 55 ›› Issue (3): 111-122.DOI: 10.1016/j.cjche.2022.06.001

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Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

Songsong Wang¹, Hong Li², Changyuan Tao^1,3, Renlong Liu^1,3, Yundong Wang⁴, Zuohua Liu^1,3

1. School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
2. Graduate School, Chongqing University, Chongqing 400044, China;
3. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing 400044, China;
4. Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

Received:2022-03-25 Revised:2022-05-31 Online:2023-06-03 Published:2023-03-28
Contact: Zuohua Liu,E-mail:liuzuohua@cqu.edu.cn
Supported by:
This work was supported by the National Natural Science Foundation of China (22078030, U1802255), National Key Research and Development Project (2019YFC1905802), 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).

Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

Songsong Wang¹, Hong Li², Changyuan Tao^1,3, Renlong Liu^1,3, Yundong Wang⁴, Zuohua Liu^1,3

1. School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
2. Graduate School, Chongqing University, Chongqing 400044, China;
3. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing 400044, China;
4. Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

通讯作者: Zuohua Liu,E-mail:liuzuohua@cqu.edu.cn
基金资助:
This work was supported by the National Natural Science Foundation of China (22078030, U1802255), National Key Research and Development Project (2019YFC1905802), 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).

Abstract

Abstract: The hydrodynamic performance of three mixers (single shaft central mixer (SSC), single shaft off-centred mixer (SSO), dual shaft off-centred mixer (DSO), was investigated in the mixing of yield-pseudoplastic fluids (xanthan gum solutions) in the laminar regime. To explore and determine the efficiency of three mixers, both numerical and experimental approaches were adopted. The fluid rheology was described by the Herschel–Bulkley rheological model. Computational fluid dynamics was employed to simulate the apparent viscosity distribution, mixing time, and the flow pattern inside the stirred tank. The developed model was validated through experimentally measured torque. The influence mechanism of the rotational speed and fluid rheology on the cavern evolution was explored deeply. The performances of three mixers in this work were compared at the constant power input and fluid rheology with respect to the flow pattern, mixing time, and mixing efficiency. The results verify that the faster the rotating speed, the greater influence of the fluid rheology on the cavern evolution, and the more uniform apparent viscosity distribution. Moreover, the mixing time decreases continuously as the increasing power consumption per unit volume, and the dimensionless mixing time of DSO mixer was nearly 42.8% and 6.1% shorter than that of SSC and SCO mixer at the same Reynolds number, respectively. According to the mixing efficiency criteria, these data also revealed that DSO was more efficient than SSC and SSO.

Key words: Cavern, Apparent viscosity, Mixing, Yield-pseudoplastic fluids, Computational fluid dynamics (CFD)

摘要： The hydrodynamic performance of three mixers (single shaft central mixer (SSC), single shaft off-centred mixer (SSO), dual shaft off-centred mixer (DSO), was investigated in the mixing of yield-pseudoplastic fluids (xanthan gum solutions) in the laminar regime. To explore and determine the efficiency of three mixers, both numerical and experimental approaches were adopted. The fluid rheology was described by the Herschel–Bulkley rheological model. Computational fluid dynamics was employed to simulate the apparent viscosity distribution, mixing time, and the flow pattern inside the stirred tank. The developed model was validated through experimentally measured torque. The influence mechanism of the rotational speed and fluid rheology on the cavern evolution was explored deeply. The performances of three mixers in this work were compared at the constant power input and fluid rheology with respect to the flow pattern, mixing time, and mixing efficiency. The results verify that the faster the rotating speed, the greater influence of the fluid rheology on the cavern evolution, and the more uniform apparent viscosity distribution. Moreover, the mixing time decreases continuously as the increasing power consumption per unit volume, and the dimensionless mixing time of DSO mixer was nearly 42.8% and 6.1% shorter than that of SSC and SCO mixer at the same Reynolds number, respectively. According to the mixing efficiency criteria, these data also revealed that DSO was more efficient than SSC and SSO.

关键词: Cavern, Apparent viscosity, Mixing, Yield-pseudoplastic fluids, Computational fluid dynamics (CFD)

Songsong Wang, Hong Li, Changyuan Tao, Renlong Liu, Yundong Wang, Zuohua Liu. Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids[J]. Chinese Journal of Chemical Engineering, 2023, 55(3): 111-122.

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Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

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