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一种超高扬程单壳体卧式多级离心泵研究Studyofasuperhigh-liftmulti-stagesinglecasinghorizontalcentrifugalpump某生物发电电厂扩建2×130t/h高温超高压循环流化床锅炉,1×30MW抽汽背压式汽轮机,1×35MW发电机，要求配带辅机单壳体锅炉离心泵流量为143m³/h，扬程1950m。Abio-powerplantwillhaveanexpansionfor2x130t/hhightemperature&superhighpressurecirculatingfluidizedbedboiler;1x30MWextractionbackpressureturbineand1x35MWgeneratorthatrequiredtobeequippedwithauxiliarysinglecasingcentrifugalboilerpumpwithflowof143m3/h,headof1950m.国内现有的单壳体锅炉离心泵系列产品最高扬程为1500m。针对此问题本文通过理论分析、数值模拟以及试验相结合的方法深入研究，为此需开发满足项目参数且无驼峰[1]、性能好、结构可靠稳定的单壳体卧式多级离心泵产品。本课题基于原有的1500m扬程单壳体锅炉离心泵通过增加级数来提高离心泵的扬程，设计出新产品QDG145-1950，但由于设计压力的增加，设计尺寸的变化等，需要对泵的各部位零件进行强度校核，并且分析新型泵在各工况条件下的运行状态。所以首先通过研究轴的强度，键、联轴器、叶轮和平衡盘的强度，壳体的强度，穿杠及密封挤压面的强度，进出口法兰的强度，看是否符合要求。然后研究泵的临界转速。其次，使用三维软件对泵进行三维实体建模。将于过流无关部分简化，并将模型理想化处理。再利用Gambit软件对模型处理，将过流部分画出，并对模型划分非结构化网格。最后，使用CFD软件(ComputationalFluidDynamics）对泵各工况条件下流道内不同位置的压力、速度的分布情况进行模拟[2]，观察流场内部压力变化，分析能产生汽蚀的条件。得到能够产生汽蚀现象的运行参数，在使用操作过剩中避免在此参数下运行[3]。Amongexistingdomesticseriesofcentrifugalboilerpumpofsingleshell,thehighestliftis1500m.Forthislimitthisarticlethroughdeepresearchesbyacombinationoftheoreticalanalysis,numericalsimulationandtest,gotaconclusionthattomeetthisprojectneedahigh-headsingleshellhorizontalmulti-stagecentrifugalpumpmustbedeveloped,anditmustbeofgoodperformance,nohumpparametersandreliablestructurestability.Basingontheoriginal1500mheadsingleshellboilercentrifugalpumpthroughincreasingthepumpstagesthissubjectintendtoimprovetheliftofcentrifugalpump,havedesignedanewproductQDG145-1950,butcausinganincreaseinthedesignpressure,andsizechangeetc,soit’snecessarytomakestrengthverificationsondifferentpartsofthepump,andanalysisofthenewtypeofpumpunderdifferentconditionsofoperationstate.Sofirstofall,bystudyofthestrengthoftheshaft,shaftcoupling,keys,impellerandthebalanceplate,thestrengthoftheshellandthefasteningrods,andthestrengthofsealingcompressivesurfaces,inletandoutletflangestrength,toseewhethertheymeettherequirements,thenanalysisonpumpcriticalspeeds.Secondly,made3Dsolidmodelingofthenewpumpbyusingthesoftware,tosimplifythosepartsthatindependentfromthemedia,andmadeanidealtreatmentofthemodel.ThenbyusingGambitsoftwaremakethemodelperfectandgetdrawingsofthepartsthatcontactingtheflowmedia,andalsomadedivisionoftheunstructuredgridforthemodel.Finally,underdifferentconditionbyusingCFDsoftware(ComputationalFluidDynamics)tosimulatethedistributionofpressureandspeedatdifferentpositionwithinthepumpflowchannels,andobservethechangeofpressureofflowfieldtoanalyzetheoccasionsforcavitationerosionandgettherunningparametersunderwhichcavitationphenomenonisabletobegenerated,sotoavoidrunningatsuchparametersinoperation.超高扬程多级离心泵使用运行过程中，极易出现汽蚀现象，汽蚀对泵的损害非常严重[4]，直接影响了泵的使用寿命，更严重的会发生转子抱死、锅炉停机的严重后果[5]。本课题首先对改进的多级离心泵进行理论进行分析研究，奠定了理论基础，然后通过Fluent模拟分析其汽蚀状态，得到会产生汽蚀现象的条件。避免在汽蚀工况运行可运转5年内不需要大修，极大的节约了设备和人工成本。关键词：多级离心泵，三维建模，汽蚀，数值模拟Theultrahighliftmulti-stagecentrifugalpumpappearsextremelyeasytocausecavitationinitsrunningprocess,whichisaveryseriousdamagetothepumpanddirectlyaffectstheservicelifeofapump,inmoreseriouscaseitwillcausetherotorlocking,boilershutdown.Firstly,throughanalysisandresearchonthetheoryoftheimprovedmulti-stagecentrifugalpumpthearticlelaiddownthetheoreticalfoundation,andthenthroughtheFluentsimulationanalysisoftheconditionofcavitation,gettheoccasionsforthecavitationphenomenon,sobyavoidingtorununderthecavitationworkingcondition,thepumpcanrun5yearsneedlessamajorrepairing,thiswillsavethecostsinequipmentsandlaborsgreatly.Keywords:Multistagecentrifugalpump,3Dmodeling,cavitation,numericalsimulation