Experimental study of hydrodynamics and bubble size distribution of an external loop airlift reactor

Lu, Xiaofeng; Ding, Yigang; Yu, Jiuyang; Long, Bingwen; Zheng, Xing

doi:10.1002/cjce.23456

Cited by 8 publications

(1 citation statement)

References 37 publications

(42 reference statements)

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“…Lu et al studied the hydrodynamic characters in a laboratory scale ALR by the experimental method, the velocity field was measured by using the particle image velocimetry technique, and the bubble size distribution was obtained by digital image analysis. The experimental results showed that the liquid flow had an unsteady structure and the wake oscillation of the bubble was asymmetrical, as the superficial gas velocity increased, the probability density function curve of bubble size changed from unimodal to bimodal [16]. Luo and Al-Dahhan adopted the CARPT technique to measure the distributions of liquid velocity, turbulent kinetic energy, and gas holdup in an ALR and observed that as the increase of the superficial velocity, the flow regime would change from bubbly flow to churn-turbulent flow [2].…”

Section: Introductionmentioning

confidence: 99%

A Turbulent Mass Diffusivity Model for Predicting Species Concentration Distribution in the Biodegradation of Phenol Wastewater in an Airlift Reactor

Li¹,

Hao²,

Jin³

et al. 2023

Processes

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In this study, a three-dimensional CFD transient model is established for predicting species concentration distribution in the biodegradation of phenol in an airlift reactor (ALR). The gas–liquid flow in the ALR is determined by the Euler–Euler method coupled with the standard k-ε model, and the bubble size is predicted by the population balance model (PBM). A turbulent mass diffusivity model is developed to simulate the turbulent mass transfer process and to predict the species concentration distribution. No empirical methods are needed as the turbulent mass diffusivity can be expressed by the concentration variance c2¯ and its dissipation rate εc. A good agreement is found between simulated and experimental results in the literature. It is not reasonable to assume a constant turbulent Schmidt number because the calculated distribution of turbulent mass diffusivity is not identical to that of turbulent viscosity. Finally, the hydrodynamic characteristics and biodegradation performance of the proposed model in a novel ALR are compared with that in the original ALR.

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Section: Introductionmentioning

confidence: 99%

A Turbulent Mass Diffusivity Model for Predicting Species Concentration Distribution in the Biodegradation of Phenol Wastewater in an Airlift Reactor

Li¹,

Hao²,

Jin³

et al. 2023

Processes

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Experimental study on the influence of the orifice size on hydrodynamic characteristics and bubble size distribution of an external loop airlift reactor

Zheng

Ding

et al. 2020

Can J Chem Eng

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The orifice size has a significant influence on hydrodynamic characteristics and bubble size distribution (BSD) in gas‐liquid flow. However, the mechanism of the influence of orifice size on BSD and hydrodynamic characteristics in an external loop airlift reactor (EL‐ALR) has not been fully revealed. In this work, the effects of the orifice size on hydrodynamic characteristics and BSD in a laboratory scale EL‐ALR were investigated using the particle image velocimetry (PIV) technique and digital image analysis (DIA). The results show that the transition superficial gas velocity becomes greater when the orifice size is reduced. The time‐averaged bubble velocity profiles along the riser radius are parabolic, and the shape of the time‐averaged bubble velocity curve is strongly dependent on the orifice diameter. The larger the orifice diameter, the steeper the parabolas. For sparger with lager orifice diameters, the BSD curve is bimodal even at low superficial gas velocity, and its peaks shift to a larger equivalent bubble diameter. The bubble aspect ratio appears to be related only to the equivalent diameter of the bubbles, regardless of the diameter of the orifice. It has a defined relationship between the bubble aspect ratio and the bubble equivalent diameter, and a new correlation is obtained based on the experimental data. This study will help to gain an understanding of the influence of sparger orifice size on the hydrodynamic characteristics and BSD and provide a basis for numerical simulation.

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Hydrodynamics and mass transfer of concentric-tube internal loop airlift reactors: A review

Wang

et al. 2022

Bioresource Technology

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Experimental study of hydrodynamics and bubble size distribution of an external loop airlift reactor

Cited by 8 publications

References 37 publications

A Turbulent Mass Diffusivity Model for Predicting Species Concentration Distribution in the Biodegradation of Phenol Wastewater in an Airlift Reactor

A Turbulent Mass Diffusivity Model for Predicting Species Concentration Distribution in the Biodegradation of Phenol Wastewater in an Airlift Reactor

Experimental study on the influence of the orifice size on hydrodynamic characteristics and bubble size distribution of an external loop airlift reactor

Hydrodynamics and mass transfer of concentric-tube internal loop airlift reactors: A review

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