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1、第11卷第5期环境工程学报Vol.11,No.52017年5月ChineseJournalofEnvironmentalEngineeringMay2017偏心双轴搅拌用于污泥搅拌混合的数值模拟∗朱桂华,张丽欣,王万斌,朱天宏中南大学机电工程学院,长沙410083摘要在大型污泥搅拌机中探索采用偏心双轴搅拌,使用Fluent软件对偏心双轴搅拌槽内污泥流体的流场变化进行数值模拟,并与中心双层搅拌进行比较,分析2种结构搅拌槽内宏观流场结构、速度分布及功耗特性,通过实验测量不同转速下偏心双轴的功耗,仿真计算结果和实验值吻合较好。结果表明:偏心双轴搅拌形成的流场
2、结构打破了中心搅拌的流场对称性,有效的消除了隔离区。偏心双轴搅拌槽内流场各方向的速度分量均比中心双层搅拌有明显的提高,速度梯度较大,-1能够增大搅拌混合区,有利于污泥固液两相的混合。在N=5r·s时偏心双轴搅拌的功耗约为中心双层搅拌的90.4%,具有明显的节能效果。关键词偏心双轴;数值模拟;速度分布;流场结构中图分类号X705文献标识码A文章编号1673-9108(2017)05-3128-07DOI10.12030/j.cjee.201601157Numericalsimulationofmixingonsludgewitheccentricityd
3、ouble-impeller∗ZHUGuihua,ZHANGLixin,WANGWanbin,ZHUTianhongSchoolofMechanicalandElectricalEngineering,CentralSouthUniversity,Changsha410083,ChinaAbstractTheeffectsoftheapplicationofaneccentricdouble-impellerwithinalargestirredtanksystemwereexploredinthisstudy.Specifically,numeric
4、alsimulationsofthegranularsludgeflowfieldinastirredtanke-quippedwithaneccentricdouble-impellerandoneequippedwithacentereddouble-impellerwereconductedbyusingFluentsoftware.Then,numericalanalysesoftheflowpattern,velocitydistribution,andpowerconsump-tionintheabovetwosystemswerecarr
5、iedoutbasedonthesimulationresults.Moreover,powerconsumptionlev-elsfortheeccentricdouble-impellersystemunderdifferentrotationalspeedswerealsomeasuredinexperiments.Theresultsshowedthatthesimulatedresultscorrespondedwellwiththeexperimentalones.Theflowpatterncausedbytheeccentricdoub
6、le-impellerwasasymmetrical,andthisdestroyedtheisolatedregionandimprovedthemixingefficiency.Theflowvelocityandvelocitygradientinducedbytheeccentricdouble-impellerwerebothhigherthanthoseinducedbythecentereddouble-impeller,whichexpandedthestirringregionandmadethemixingofthesolid-li
7、quidtwo-phasematerialmoreefficient.Thepowerconsumptionfortheeccentricdouble-im--1pellerunder5r·srotationalspeedwasjust90.4%ofthatofthecentereddouble-impeller.Keywordseccentricitydouble-impeller;numericalsimulation;flowpattern;velocitydistribution在进行污泥无害化处理的典型工艺中,为了提高污泥的脱水效率,大多需要
8、向流态的污泥里面添加固体颗粒来增加污泥的渗透性。污泥作为一种高黏度的非牛顿流体,具有混合传质能
