Gas-liquid hydrodynamics in a vessel stirred by dual dislocated-blade Rushton impellers

doi:10.1016/j.cjche.2015.09.002

Abstract

Abstract: Towards the objective of improving the gas dispersion performance, the dislocated-blade Rushton impeller was applied to the gas-liquid mixing in a baffled stirred vessel. The flow field, gas hold-up, dissolved oxygen, power consumption before and after gassing were studied using the computational fluid dynamics (CFD) technique. Dispersion of gas in the liquid was modelled using the Eulerian-Eulerian approach along with the dispersed k-ε turbulent model. Rotation of the impeller was simulated with the multiple reference frame method. A modified drag coefficient which includes the effect of turbulence was used to account for the momentum exchange. The predictions were compared with their counterparts of the standard Rushton impeller and were validated with the experimental results. It is concluded that the dislocated-blade Rushton impeller is superior to the standard Rushton impeller in the gas-liquid mixing operation, and the findings obtained here lay the basis of its application in process industries.

Key words: Stirred vessel, Gas-liquid mixing, Dislocated-blade Rushton impeller, Power consumption, Computational fluid dynamics (CFD)

摘要： Towards the objective of improving the gas dispersion performance, the dislocated-blade Rushton impeller was applied to the gas-liquid mixing in a baffled stirred vessel. The flow field, gas hold-up, dissolved oxygen, power consumption before and after gassing were studied using the computational fluid dynamics (CFD) technique. Dispersion of gas in the liquid was modelled using the Eulerian-Eulerian approach along with the dispersed k-ε turbulent model. Rotation of the impeller was simulated with the multiple reference frame method. A modified drag coefficient which includes the effect of turbulence was used to account for the momentum exchange. The predictions were compared with their counterparts of the standard Rushton impeller and were validated with the experimental results. It is concluded that the dislocated-blade Rushton impeller is superior to the standard Rushton impeller in the gas-liquid mixing operation, and the findings obtained here lay the basis of its application in process industries.

关键词: Stirred vessel, Gas-liquid mixing, Dislocated-blade Rushton impeller, Power consumption, Computational fluid dynamics (CFD)

Fengling Yang, Shenjie Zhou, Xiaohui An. Gas-liquid hydrodynamics in a vessel stirred by dual dislocated-blade Rushton impellers[J]. Chin.J.Chem.Eng., 2015, 23(11): 1746-1754.

Fengling Yang, Shenjie Zhou, Xiaohui An. Gas-liquid hydrodynamics in a vessel stirred by dual dislocated-blade Rushton impellers[J]. Chinese Journal of Chemical Engineering, 2015, 23(11): 1746-1754.

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