Article: Numerical simulations of fluid dynamics and mixing in a large shallow bubble column: effects of the sparging pipe allocations for multiple-pipe gas distributors Journal: International Journal of Engineering Systems Modelling and Simulation (IJESMS) 2009 Vol.1 No.2/3 pp.165 - 175 Abstract: Numerical simulations of gas-liquid flow in a bubble column of 800 mm in diameter using two-fluid model and multi-size-group (MUSIG) model were conducted to investigate the effect of allocation of sparging pipes in gas distributors on hydrodynamic flow, gas hold-up, mixing characteristics, turbulence and bubble size. In the simulation, six different arrangements were assessed, which four-sparging pipes are mounted to a gas distributor with the allocation ring to bubble column ratios (d/DT) being 0.3, 0.37, 0.4, 0.5, 0.6 and 0.7, respectively. The simulation results have clearly demonstrated that the allocation of sparging pipes to the gas distributor has an important impact on gas hold-up and mixing characteristics. It was found from the simulations that the mixing time and overall gas hold-up increase initially with the increase of d/DT but decrease with further increase of d/DT. As a result, it was revealed that the optimum value of d/DT is around 0.4 for the highest overall gas hold-up and is confirmed by the experiment. It was also indicated from the simulation that d/DT of 0.5 yields the maximum mixing time. Inderscience Publishers - linking academia, business and industry through research

Title: Numerical simulations of fluid dynamics and mixing in a large shallow bubble column: effects of the sparging pipe allocations for multiple-pipe gas distributors

Authors: Guang Li, Qingbai Cai, Gance Dai, Xiaogang Yang

Addresses: State Key Laboratory of Chemical Reactors, East China University of Science and Technology, Shanghai 200237, China. ' State Key Laboratory of Chemical Reactors, East China University of Science and Technology, Shanghai 200237, China. ' State Key Laboratory of Chemical Reactors, East China University of Science and Technology, Shanghai 200237, China. ' School of Science and Technology, Glyndwr University, Wrexham LL11 2AW, UK

Abstract: Numerical simulations of gas-liquid flow in a bubble column of 800 mm in diameter using two-fluid model and multi-size-group (MUSIG) model were conducted to investigate the effect of allocation of sparging pipes in gas distributors on hydrodynamic flow, gas hold-up, mixing characteristics, turbulence and bubble size. In the simulation, six different arrangements were assessed, which four-sparging pipes are mounted to a gas distributor with the allocation ring to bubble column ratios (d/D_T) being 0.3, 0.37, 0.4, 0.5, 0.6 and 0.7, respectively. The simulation results have clearly demonstrated that the allocation of sparging pipes to the gas distributor has an important impact on gas hold-up and mixing characteristics. It was found from the simulations that the mixing time and overall gas hold-up increase initially with the increase of d/D_T but decrease with further increase of d/D_T. As a result, it was revealed that the optimum value of d/D_T is around 0.4 for the highest overall gas hold-up and is confirmed by the experiment. It was also indicated from the simulation that d/D_T of 0.5 yields the maximum mixing time.

Keywords: CFD modelling; multiphase flow; multiple pipe gas distributors; shallow bubble column; two-fluid model; turbulence modelling; computational fluid dynamics; gas-liquid flow; sparging pipes; hydrodynamic flow; gas hold-up; mixing characteristics; bubble size; simulation.

DOI: 10.1504/IJESMS.2009.027580

International Journal of Engineering Systems Modelling and Simulation, 2009 Vol.1 No.2/3, pp.165 - 175

Published online: 01 Aug 2009 *

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Title: Numerical simulations of fluid dynamics and mixing in a large shallow bubble column: effects of the sparging pipe allocations for multiple-pipe gas distributors

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