李花,潘艳秋,俞路,沈驭臣,何德民

• 1:大连理工大学化工学院

摘要(Abstract)：

针对管状煤基炭膜气隙式膜蒸馏过程通量低的问题,进行膜蒸馏氯化钠溶液气液两相流强化实验及CFD模拟研究,探讨两相流流型和气含率对强化过程的影响。实验结果表明:N2流量对渗透通量影响的模拟结果与实验结果吻合较好。当进料流量为40 L×hh~(-1)、N2流量为50 L×h~(-1) (气含率0.56)时,对应团状流,此时强化传质效果最好。模拟结果中强化过程的膜壁剪应力(约1.77 N×m~(-2))明显大于无强化过程(约0.015 N×m~(-2))。流动方向上,经强化后大小与方向均变化的剪应力可增强对料液的扰动进而增大渗透通量,也可降低膜污染与浓度极化程度进而延长操作时间。气含率不大于0.56b (泡状流、塞状流与团状流)时,随着气含率增大,气泡群对料液的扰动作用增强,强化传质效果变好;气含率大于0.56 (乳沫流与环状流)后,两相间出现较为明显且稳定的界面,扰动作用相比团状流时变差。利用CFD方法模拟得到的膜壁剪应力、气液两相流型、速度分布、湍流强度规律可用于定性分析两相流强化过程,为进一步探究该过程强化传质机理提供依据。

关键词(KeyWords)： 膜蒸馏;两相流;过程强化;海水淡化;CFD

Abstract:

Keywords:

基金项目(Foundation): 中央高校基本业务费(DUT17JC07)

作者(Author): 李花,潘艳秋,俞路,沈驭臣,何德民

参考文献(References)：

• [1]BAGHBANZADEH M,RANA D,LAN C Q.Zero thermal input membrane distillation,a zero-waste and sustainable solution for freshwater shortage[J].Applied Energy,2017,187:910-928.
• [2]ALSAADI A S,FRANCIS L,MAAB H,et al.Evaluation of air gap membrane distillation process running under sub-atmospheric conditions?:experimental and simulation studies[J].Journal of Membrane Science,2015,489:73-80.
• [3]DING Z,LIU L,LIU Z,et al.The use of intermittent gas bubbling to control membrane fouling in concentrating TCM extract by membrane distillation[J].Journal of Membrane Science,2011,372(1/2):172-181.
• [4]CHEN G,YANG X,LU Y,et al.Heat transfer intensification and scaling mitigation in bubbling-enhanced membrane distillation for brine concentration[J].Journal of Membrane Science,2014,470:60-69.
• [5]WU C R,JIA Y,CHEN H Y,et al.Study on air-bubbling strengthened membrane distillation process[J].Desalination and Water Treatment,2011,34(1/2/3):2-5.
• [6]WU C R,LI Z G,ZHANG J H,et al.Study on the heat and mass transfer in air-bubbling enhanced vacuum membrane distillation[J].Desalination,2015,373:16-26.
• [7]AZBEL D.Two-phase flows in chemical engineering[M].Cambridge:Cambridge University Press,1981.
• [8]TAHA T,CUI Z F.CFD modelling of gas-sparged ultrafiltration in tubular membranes[J].Journal of Membrane Science,2002,210(1):13-27.
• [9]NDINISA N V,WILEY D E,FLETCHER D F.Computational fluid dynamics simulations of Taylor bubbles in tubular membranes model validation and application to laminar flow systems[J].Chemical Engineering Research and Design,2005,83(A1):40-49.
• [10]GUPTA R,FLETCHER D F,HAYNES B S.On the CFD modelling of Taylor flow in microchannels[J].Chemical Engineering Science,2006,64(12):2941-2950.
• [11]SMITH S,TAHA T,CUI Z F.Enhancing hollow fibre ultrafiltration using slug-flow-a hydrodynamic study[J].Desalination,2002,146(1/2/3):69-74.
• [12]张金赫,李花,沈驭臣,等.膜蒸馏海水淡化过程中的两相流强化实验研究[J].高校化学工程学报,2018,32(1):38-43.ZHANG J H,LI H,SHEN Y C,et al.Experimental investigation on two-phase flow enhancement of desalination processes via membrane distillation[J].Journal of Chemical Engineering of Chinese Universities,2018,32(1):38-43.
• [13]沈驭臣.膜蒸馏海水淡化过程两相流强化与CFD模拟[D].大连:大连理工大学,2016.SHEN Y C.Two-phase flow enhancement and CFD simulation of membrane distillation process for seawater desalination[D].Dalian:Dalian University of Technology,2016.
• [14]WU C,LI Z,ZHANG J,et al.Study on the heat and mass transfer in air-bubbling enhanced vacuum membrane distillation[J].Desalination,2015,373:16-26.
• [15]Fluent Inc.Fluent 6.3 user’s guide[Z].America:Fluent Inc,2006.
• [16]WANG T,ZHANG Z G,REN X J,et al.Direct observation of single-and two-phase flows in spacer filled membrane modules[J].Separation and Purification Technology,2014,125:275-283.
• [17]WIBISONO Y,CORNELISSEN E R,KEMPERMAN A J,et al.Two-phase flow in membrane processes:a technology with a future[J].Journal of Membrane Science,2014,453:566-602.
• [18]CUI Z F,CHANG S,FANE A G.The use of gas bubbling to enhance membrane processes.Journal of Membrane Science,2003,221(1/2):1-35.
• [19]SMITH S R,FIELD R W,CUI Z F.Predicting the performance of gas-sparged and non-gas-sparged ultrafiltration[J].Desalination,2006,191(1/2/3):376-385.
• [20]TAHA T,CHEONG W L,FIELD R W,et al.Gas-sparged ultrafiltration using horizontal and inclined tubular membranes-A CFDstudy[J].Journal of Membrane Science,2006,279(1/2):487-494.