{"title":"The flow and mass transfer characteristics of concentric gas-liquid flow in an advanced static mixer","authors":"Huibo Meng, Zhonggen Li, Yanfang Yu, Mengqi Han, Shuning Song, Xiu-Hui Jiang, Zongyong Wang, Jianhua Wu","doi":"10.2298/ciceq191213024m","DOIUrl":null,"url":null,"abstract":"The fluid dynamic and mass transfer characteristics of concentric upward gas-liquid flow were studied in an industrial static mixer with four equally spaced helical inserts (FKSM). The numerical simulations of the gas volume fraction in a Kenics mixer was in good agreement with the numerical and experimental results provided by Rabha et al. The characteristics of radial gas void fraction and local mass transfer coefficients in the FKSM were evaluated under different operating conditions. The velocity profiles of the concentric air phase accelerated by the bubble forces first became sharp and narrow until z/l = = -3.27 and then slowly decreased and stabilized at z/l = -1.5 before entering the first mixing element. Some extra unimodal profile of radial gas holdup gradually generated near the rectangle cross-sections of the mixing elements. The ?G gradually enlarged from r/R = 0.2 to r/R = 0.55 and then weakened from r/R = 0.65 to r/R = 0.874. The air void fractions in the bulk flow region decreased with the increasing initial uniform bubble diameter. The inlet effect of the first leading edge enhanced the air phase dispersion and local mass transfer coefficients sharply increased from 2.04 to 3.69 times of that in the inlet. The local mass transfer coefficients in each mixing group had unimodal profiles.","PeriodicalId":9716,"journal":{"name":"Chemical Industry & Chemical Engineering Quarterly","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Industry & Chemical Engineering Quarterly","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.2298/ciceq191213024m","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 1
Abstract
The fluid dynamic and mass transfer characteristics of concentric upward gas-liquid flow were studied in an industrial static mixer with four equally spaced helical inserts (FKSM). The numerical simulations of the gas volume fraction in a Kenics mixer was in good agreement with the numerical and experimental results provided by Rabha et al. The characteristics of radial gas void fraction and local mass transfer coefficients in the FKSM were evaluated under different operating conditions. The velocity profiles of the concentric air phase accelerated by the bubble forces first became sharp and narrow until z/l = = -3.27 and then slowly decreased and stabilized at z/l = -1.5 before entering the first mixing element. Some extra unimodal profile of radial gas holdup gradually generated near the rectangle cross-sections of the mixing elements. The ?G gradually enlarged from r/R = 0.2 to r/R = 0.55 and then weakened from r/R = 0.65 to r/R = 0.874. The air void fractions in the bulk flow region decreased with the increasing initial uniform bubble diameter. The inlet effect of the first leading edge enhanced the air phase dispersion and local mass transfer coefficients sharply increased from 2.04 to 3.69 times of that in the inlet. The local mass transfer coefficients in each mixing group had unimodal profiles.
研究了四个等间距螺旋插片(FKSM)工业静态混合器内气液同心向上流动的流体动力学和传质特性。对Kenics混合器内气体体积分数的数值模拟与Rabha等人的数值和实验结果吻合较好。研究了不同工况下FKSM内径向气隙率和局部传质系数的特性。在气泡力加速下,同心气相的速度分布在z/l = = -3.27处首先变得尖细狭窄,然后在z/l = -1.5处缓慢减小并趋于稳定,进入第一个混合单元。在混合单元的矩形截面附近,逐渐产生了一些额外的径向气含率单峰分布。从r/ r = 0.2逐渐增大到r/ r = 0.55,再从r/ r = 0.65逐渐减弱到r/ r = 0.874。随着初始均匀气泡直径的增大,散流区空隙率减小。第一前缘的入口效应增强了气相弥散,局部传质系数由入口的2.04倍急剧增加到3.69倍。各混合组的局部传质系数呈单峰分布。
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