SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2020, Vol. 28 ›› Issue (9): 2235-2247.DOI: 10.1016/j.cjche.2020.06.016

• Fluid Dynamics and Transport Phenomena • 上一篇    下一篇

Numerical simulation of micro-mixing in gas-liquid and solid-liquid stirred tanks with the coupled CFD-E-model

Xiaoxia Duan1,2, Xin Feng1,2, Chong Peng3, Chao Yang1,2, Zaisha Mao1   

  1. 1 CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 SINOPEC Dalian Research Institute of Petroleum and Petrochemicals, Dalian 116045, China
  • 收稿日期:2020-03-02 修回日期:2020-06-08 出版日期:2020-09-28 发布日期:2020-10-21
  • 通讯作者: Xin Feng
  • 基金资助:
    This work was supported by the National Key Research and Development Program (2016YFB0301702), the National Natural Science Foundation of China (21808221, 21776282, 21938009), Major Research Plan of NSFC (91934301); the Key Research Program of Frontier Sciences, CAS (QYZDJ-SSW-JSC030), the Key Research Program of Nanjing IPE Institute of Green Manufacturing Industry (No. E0010719) and the Youth Innovation Promotion Association CAS.

Numerical simulation of micro-mixing in gas-liquid and solid-liquid stirred tanks with the coupled CFD-E-model

Xiaoxia Duan1,2, Xin Feng1,2, Chong Peng3, Chao Yang1,2, Zaisha Mao1   

  1. 1 CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 SINOPEC Dalian Research Institute of Petroleum and Petrochemicals, Dalian 116045, China
  • Received:2020-03-02 Revised:2020-06-08 Online:2020-09-28 Published:2020-10-21
  • Contact: Xin Feng
  • Supported by:
    This work was supported by the National Key Research and Development Program (2016YFB0301702), the National Natural Science Foundation of China (21808221, 21776282, 21938009), Major Research Plan of NSFC (91934301); the Key Research Program of Frontier Sciences, CAS (QYZDJ-SSW-JSC030), the Key Research Program of Nanjing IPE Institute of Green Manufacturing Industry (No. E0010719) and the Youth Innovation Promotion Association CAS.

摘要: The coupled CFD-E-model for multiphase micro-mixing was developed, and used to predict the micro-mixing effects on the parallel competing chemical reactions in semi-batch gas-liquid and solid-liquid stirred tanks. Based on the multiphase macro-flow field, the key parameters of the micro-mixing E-model were obtained with solving the Reynolds-averaged transport equations of mixture fraction and its variance at low computational costs. Compared with experimental data, the multiphase numerical method shows the satisfactory predicting ability. For the gas-liquid system, the segregated reaction zone is mainly near the feed point, and shrinks to the exit of feed-pipe when the feed position is closer to the impeller. Besides, surface feed requires more time to completely exhaust the added H+ solution than that of impeller region feed at the same operating condition. For the solid- liquid system, when the solid suspension cloud is formed at high solid holdups, the flow velocity in the clear liquid layer above the cloud is notably reduced and the reactions proceed slowly in this almost stagnant zone. Therefore, the segregation index in this case is larger than that in the dilute solid-liquid system.

关键词: Stirred tank, Engulfment model (E-model), Multiphase flow, Micro-mixing, Computational fluid dynamics (CFD), Simulation

Abstract: The coupled CFD-E-model for multiphase micro-mixing was developed, and used to predict the micro-mixing effects on the parallel competing chemical reactions in semi-batch gas-liquid and solid-liquid stirred tanks. Based on the multiphase macro-flow field, the key parameters of the micro-mixing E-model were obtained with solving the Reynolds-averaged transport equations of mixture fraction and its variance at low computational costs. Compared with experimental data, the multiphase numerical method shows the satisfactory predicting ability. For the gas-liquid system, the segregated reaction zone is mainly near the feed point, and shrinks to the exit of feed-pipe when the feed position is closer to the impeller. Besides, surface feed requires more time to completely exhaust the added H+ solution than that of impeller region feed at the same operating condition. For the solid- liquid system, when the solid suspension cloud is formed at high solid holdups, the flow velocity in the clear liquid layer above the cloud is notably reduced and the reactions proceed slowly in this almost stagnant zone. Therefore, the segregation index in this case is larger than that in the dilute solid-liquid system.

Key words: Stirred tank, Engulfment model (E-model), Multiphase flow, Micro-mixing, Computational fluid dynamics (CFD), Simulation