Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model

Qi Xu; Jiakuan Yang; Huijie Hou; Yuchen Hu; Sha Liang; Keke Xiao; Xu Wu; Bingchuan Liu; Jingping Hu; Jiukun Hu; Changzhu Yang

doi:10.2166/wst.2018.472

Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model

Qi Xu, Jiakuan Yang^*, Huijie Hou, Yuchen Hu, Sha Liang, Keke Xiao, Xu Wu, Bingchuan Liu, Jingping Hu, Jiukun Hu, Changzhu Yang

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

A liquid-gas two-phase computational fluid dynamics (CFD) model was developed to simulate flow field and gas hold-up in a pilot-scale oxidation ditch (OD). The volume of fluid (VOF) model and the mass flow inlet boundary condition for gas injection were introduced in this model. The simulated values of the flow velocities and the gas hold-up were verified by experimental measurements in the pilot-scale OD. The results showed that the gas hold-up at test-site 3, immediately downstream of the surface aerator, was the highest among all three test-sites. Most of the gas existed in the upper portion of the ditch and was close to the inner side of the channel. Based on the liquid-gas two-phase CFD model, three operating conditions with different setting height ratios of the submerged impellers were simulated. The simulated results suggested that the setting heights of the submerged impellers have significant impacts on the flow velocity distribution. Lowering the setting height could increase the flow velocity in the pilot-scale OD. An optimal setting height ratio of 0.273 was proposed, which would be beneficial for minimizing sludge sedimentation, especially near the inner side of the curve bend.

Original language	English
Pages (from-to)	1956-1965
Number of pages	10
Journal	Water Science and Technology
Volume	78
Issue number	9
DOIs	https://doi.org/10.2166/wst.2018.472
State	Published - 19 Dec 2018
Externally published	Yes

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@article{60d197579e3b40119271d77c5e1c9d6c,

title = "Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model",

abstract = "A liquid-gas two-phase computational fluid dynamics (CFD) model was developed to simulate flow field and gas hold-up in a pilot-scale oxidation ditch (OD). The volume of fluid (VOF) model and the mass flow inlet boundary condition for gas injection were introduced in this model. The simulated values of the flow velocities and the gas hold-up were verified by experimental measurements in the pilot-scale OD. The results showed that the gas hold-up at test-site 3, immediately downstream of the surface aerator, was the highest among all three test-sites. Most of the gas existed in the upper portion of the ditch and was close to the inner side of the channel. Based on the liquid-gas two-phase CFD model, three operating conditions with different setting height ratios of the submerged impellers were simulated. The simulated results suggested that the setting heights of the submerged impellers have significant impacts on the flow velocity distribution. Lowering the setting height could increase the flow velocity in the pilot-scale OD. An optimal setting height ratio of 0.273 was proposed, which would be beneficial for minimizing sludge sedimentation, especially near the inner side of the curve bend.",

author = "Qi Xu and Jiakuan Yang and Huijie Hou and Yuchen Hu and Sha Liang and Keke Xiao and Xu Wu and Bingchuan Liu and Jingping Hu and Jiukun Hu and Changzhu Yang",

note = "Publisher Copyright: {\textcopyright} IWA Publishing 2018.",

year = "2018",

month = dec,

day = "19",

doi = "10.2166/wst.2018.472",

language = "英语",

volume = "78",

pages = "1956--1965",

journal = "Water Science and Technology",

issn = "0273-1223",

publisher = "IWA Publishing",

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TY - JOUR

T1 - Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model

AU - Xu, Qi

AU - Yang, Jiakuan

AU - Hou, Huijie

AU - Hu, Yuchen

AU - Liang, Sha

AU - Xiao, Keke

AU - Wu, Xu

AU - Liu, Bingchuan

AU - Hu, Jingping

AU - Hu, Jiukun

AU - Yang, Changzhu

PY - 2018/12/19

Y1 - 2018/12/19

N2 - A liquid-gas two-phase computational fluid dynamics (CFD) model was developed to simulate flow field and gas hold-up in a pilot-scale oxidation ditch (OD). The volume of fluid (VOF) model and the mass flow inlet boundary condition for gas injection were introduced in this model. The simulated values of the flow velocities and the gas hold-up were verified by experimental measurements in the pilot-scale OD. The results showed that the gas hold-up at test-site 3, immediately downstream of the surface aerator, was the highest among all three test-sites. Most of the gas existed in the upper portion of the ditch and was close to the inner side of the channel. Based on the liquid-gas two-phase CFD model, three operating conditions with different setting height ratios of the submerged impellers were simulated. The simulated results suggested that the setting heights of the submerged impellers have significant impacts on the flow velocity distribution. Lowering the setting height could increase the flow velocity in the pilot-scale OD. An optimal setting height ratio of 0.273 was proposed, which would be beneficial for minimizing sludge sedimentation, especially near the inner side of the curve bend.

AB - A liquid-gas two-phase computational fluid dynamics (CFD) model was developed to simulate flow field and gas hold-up in a pilot-scale oxidation ditch (OD). The volume of fluid (VOF) model and the mass flow inlet boundary condition for gas injection were introduced in this model. The simulated values of the flow velocities and the gas hold-up were verified by experimental measurements in the pilot-scale OD. The results showed that the gas hold-up at test-site 3, immediately downstream of the surface aerator, was the highest among all three test-sites. Most of the gas existed in the upper portion of the ditch and was close to the inner side of the channel. Based on the liquid-gas two-phase CFD model, three operating conditions with different setting height ratios of the submerged impellers were simulated. The simulated results suggested that the setting heights of the submerged impellers have significant impacts on the flow velocity distribution. Lowering the setting height could increase the flow velocity in the pilot-scale OD. An optimal setting height ratio of 0.273 was proposed, which would be beneficial for minimizing sludge sedimentation, especially near the inner side of the curve bend.

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U2 - 10.2166/wst.2018.472

DO - 10.2166/wst.2018.472

M3 - 文章

C2 - 30566099

AN - SCOPUS:85058879290

SN - 0273-1223

VL - 78

SP - 1956

EP - 1965

JO - Water Science and Technology

JF - Water Science and Technology

IS - 9

ER -

Simulation on flow field and gas hold-up of a pilot-scale oxidation ditch by using liquid-gas CFD model

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