给水管道多相流冲洗技术的研究及应用

硕士学位论文给水管道多相流冲洗技术的研究及应用RESEARCHANDAPPLICATIONOFMULTIPHASECLEANINGTECHNOLOGYINWATERSUPPLYPIPELINES韩晓曦哈尔滨工业大学2012年7月国内图书分类号：TU991.3学校代码：10213国际图书分类号：628.1密级：公开工程硕士学位论文给水管道多相流冲洗技术的研究及应用硕士研究生：韩晓曦导师：赵明副教授副导师：郑小明高工申请学位：工程硕士学科：建筑与土木工程所在单位：市政环境工程学院答辩日期：2012年7月授予学位单位：哈尔滨工业大学ClassifiedIndex:TU991.3U.D.C:628.1DissertationfortheMasterDegreeinEngineeringRESEARCHANDAPPLICATIONOFMULTIPHASECLEANINGTECHNOLOGYINWATERSUPPLYPIPELINESCandidate：HanXiaoxiSupervisor：AssociateSupervisor：Assoc.ProfessorZhaoMingSeniorEngineerZhengXiaomingAcademicDegreeAppliedfor：MasterofEngineeringSpeciality：ArchitectureandCivilEngineeringAffiliation：SchoolofMunicipalandEnvironmentalEngineeringDateofDefence：July,2012Degree-Conferring-Institution：HarbinInstituteofTechnology哈尔滨工业大学工程硕士学位论文-I-摘要给水系统是保证城市用水，维持正常生产、生活的必不可少的重要基础设施。供水管网是给水系统的重要组成部分，随着人们对水质要求的不断提高，供水管网内水质的二次污染已经成为一个不容忽视的问题。即使出厂水水质严格达到国家饮用水标准，但如果解决不好管网的二次污染问题，最终配送到用户处的水仍然面临着不能达标的可能性。而造成管网水质恶化的主要原因，可归咎于管壁上附着的“生长环”，由于它的存在还会使管网的过水断面减小，降低管网的输水能力。为了降低“生长环”的危害，改善管网水质，提高管网供水能力，管道清洗技术不失为是一项能迅速清除管内“生长环”的首选方法。本文主要探讨基于气水脉冲技术的多相流管道清洗技术，其具有高效、绿色、环保等特点。在小试试验中，通过自行搭建的试验平台，首先探讨了不同脉冲频率、进气口喷嘴形状、进气口的位置对两相流冲洗效果的影响以及达到最佳冲洗效果的组合条件。另外，尝试在冲洗试验中加入陶粒颗粒，使冲洗过程变为气、水、固三相流，研究表明由于固体颗粒的存在，使固体经过管道中某点时，液相的静压力部分转化为固体颗粒的动能，从而加强了固体颗粒与管道内壁的摩擦剪切作用。在试验的基础上，对两相流冲洗试验进行了数值模拟的研究。通过对试验管段的简化，建立了物理网格模型；选用非定常求解器模拟一个周期内的两相流冲洗试验流动状态，得出模拟管道中各项参数的云图，和监测点处管壁剪切力随时间变化的曲线；用试验数据验证了模拟的结果；从而更直观的显示出冲洗试验中管道内的变化趋势，并为工程实际提供冲洗参数。小试试验和数值模拟的结果应用于气水脉冲管道冲洗的实际工程中，冲洗后浊度和余氯等水质指标均达到国家饮用水水质标准。气水脉冲管道冲洗技术，可以有效对给水管道内“生长环”进行清除；可以解决小管冲大管，冲洗水量不足，及被冲管段地形变化较大等问题；以经济环保的优势成为当今供水企业解决管网二次污染，提高供水效率和供水水质的重要手段。关键词：给水管网；二次污染；气水脉冲；数值模拟哈尔滨工业大学工程硕士学位论文-II-AbstractThewatersupplysystemisanessentialandvitalinfrastructurefordailyandindustrialusetomaintainnormalproductionandlivinglifeinmodernsociety.Thewatersupplynetworkisanimportantpartofthewatersupplysystem,whichiscloselylinkedtowatertransfermainpipes,secondarypumpstationsandadjustingconstructions.Withtheincreasingrequirementsonwaterqualityinoursociety,thesecondarypollutionofthewaterqualitywithinthewatersupplynetworkhasbecomeanissuethatcannotbeignored.Eventhoughtheproductwaterqualityofwaterplantsisstrictlycompliedwiththenationaldrinkingwaterstandard,theriskofwatercontaminationmaystilloccurattheusers’placeiftheproblemofsecondarypollutioninpipenetworkhasnotbeensolvedproperly.Themainreasonforthedeteriorationofwaterqualityinthepipenetworkcanbeattributedtothe“growth-ring”whichisattachedtothepipeinnerwall.What’smore,“growth-ring”couldalsoreducethecrosssectionarea,resultinginloweringthetransfercapacityofwatersupplypipenetworkInordertominimizethehazardsofthe“growth-ring”andtoimprovethewaterenvironmentinpipenetworkaswellasenhancingtheeffectivewatersupplyoutput,pipelinecleaningtechnologyisrecognizedasapreferredmethodinremovingtheimpuritiesinwaterpipesrapidly.Thispapermainlyfocusesonthemultiphasecleaningmethodwhichisbasedonthewater-gaspulsepipecleaningtechnology.Thismultiphasecleaningmethodhasmanyadvantagessuchasenvironmentalfriendlyandhigh-efficiencyetc.Inthetrialexperimentperiod,wefirstdiscussedthedifferentcombinationsofpulsefrequency,airinletnozzleshapeandthelocationofairinletontheeffectivenessoftwo-phasepipecleaningbydesigningandbuildingthetestplatform.Inaddition,ceramsiteparticleswerealsoaddedintotheexperimentpipesturningtheflushingprocessintoair-water-solidthree-phaseflowpattern.Itisfoundthatduetothesolidparticles,theliquidstaticpressureispartiallyconvertedintothekineticenergyofceramsitewhentheparticlespassingbyacertainpointwithwaterandgas,whichcontributestoincreasingtheeffectoffrictionandshearstressbetweenthree-phaseflowandtheinnerwallofthepipes.Anumericalsimulationresearchwascarriedoutonthebasisoftwo-phaseflowflushingexperiment.Aftersimplifyingexperimentpipes,aphysicalgridmodelwasestablished.Byusingtheunsteadysolver,anexperimentaltwo-phaseflowcasewithinoneflushcyclewassimulatedtoverifytheagreementbetweenexperimentaldataandsimulatedresults.Abetterandmoreintuitivevariationtrendofwaterand哈尔滨工业大学工程硕士学位论文-III-gasflowperformanceinwaterpipeisobtainedfromthesimulatedcloudsofdifferentparametersandthecurveofshearstressatmonitoringspotschangingintime.Throughapplyingwater-gaspulsepipeflushingtechnologytorealproject,thedataofwaterturbidityandresidualchlorineattheendofpipelinewasrecorded.Fromtheproject,itisconsideredthatthistechnologycouldeffectivelycleanupthepipesinthewatersupplypipenetwork.Water-gastwo-phasepulsecleaningtechnologycouldfixtheproblemusingsmallerdiametertubetoflushgreateroneaswellasmeetingtherequirementsofflushingwaterrateandamount.Insumthisflushingmethodprovideswaterworksamoreeconomicalandenvironmentalfriendlywaytosolvethesecondarypollutionindistributionsystemandensuretheefficiencyandamountofwatersupply.Keywords:watersupplynetwork,secondarypollution,water-gaspulseflushingtechnology,numericalsimulation哈尔滨工业大学工程硕士学位论文-IV-目录摘要..........................................................................................................................IABSTRACT......................................................................................