基于单、双溢流蒸馏塔板液相流场三维模拟

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1、天津大学硕士学位论文单、双溢流蒸馏塔板液相流场三维模拟姓名：刘伯潭申请学位级别：硕士专业：化学工程指导教师：余国琮2001.2.1摘要本文对单、双溢流蒸馏塔板液相流场和浓度场进行了三维数值模拟，使塔板液相流动的研究从二维水平进入到三维水平，为新型板式塔的设计提供依据。在蒸馏塔板的操作中，由于气体穿过液层，气体要和液流发生动量与质量的交换，因此在计算过程中必须在描述液相流速场的动量方程加入表达气液动量交换的源项s川在描述液相浓度场的传质方程加入表达气液质量交换的源项品。塔板流场模型是否准确取决于这两个源项的

2、精确程度。本文采用K一占模型对N．S方程进行封闭，运用化工中气液两相流关于曳力计算的理论推导出s。的形式，计算出了单、双溢流塔板液相流场；运用化工中关于相间传质系数计算的理论．推导出了＆的形式，并把传质微分方程与N．s方程，芷和占的输运方程联立求解。计算了单、双溢流塔板液相浓度场。在流场和浓度场的模拟计算中，发现了塔板回流区的纵向分布和浓度的纵向分布。本文还考察了各工况因素对流场的影响，得出结论是：回流区面积随液流强度的增大而增大，随气速的增大而减小。液相平均浓度随液流强度的增大而增大，随气速的增大而减小

3、。关键词：精馏塔橇流体力学气液两相流流体力学模型谂项J回流区●tAbstractTheliquidflowfieldsofdistillationtraywithsingle--passandtwo’passliquidflowweresimulatedonthree-dimensionalbasisinthispaper,whichdeepenedtheresearchofflowfieldofdistillationtrayandprovideinformationfordesigningnewsep

4、aratinginstruments．Forsimulatingtheflowfieldofdistillationtray,theeffectofvaporphasepassingverticallythrou曲liquidphaseshouldbeconsidered．So，％，aSOUrCeforinterphasemomentumtransfer,shouldbeaddedtoN—Sequations，and&，asourceforinterphasemasstransfer,shouldbead

5、dedtomasstransferequation．WhetherthemathematicalmodelWascorrectdependontheprecisionofthesetwosources．Inpresentstudy,K—sequationsWaSadoptedforclosingtheReynoldsequations．ByapplyingthechemicalengineeringtheoriesfordragforcesaformulaforsMtwasobtained；byapply

6、ingthechemicalengineeringtheoriesforinterphasemasstransfercoefficientaformulaforScWasobtained．Thentheliquidflowfieldandconcentrationfieldfordistillationtray、撕t11single·passandtwo-passliquidflowweresimulated．Theprofileofratioofcirculationareaandprofileofav

7、erageconcentrationalongzdirectionwerefound．Bycalculatingflowpatternsofdifferentoperatingconditions，thefollowingconclusionswereverified：whentheliquidflowrateincreased，theratioofcirculationareaincreased，theaverageconcentrationincreased；whenthevaporfloWratei

8、ncreased，theratioofcirculationareadecreased，theaverageconcentrationdecreased．Keyword：computationalfluid—dynamicsondistillationtrayvapor-liquidtwophaseflowmathematicalmodeloffluiddynamicsSOUreecirculationarea天津大学硕士学位