Page 116 - 2022年第53卷第11期
P. 116
Investigationontransientflowingcharacteristicsofhigh - head
Francisturbineduringloadreduction
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SUNLonggang,XUZhuofei,GUOPengcheng ,ZHENGXiaobo
(1.SchoolofWaterResourcesandHydroelectricEngineering,Xi’anUniversityofTechnology,Xi’an 710048,China;
2.StateKeyLaboratoryofEco - hydraulicsinNorthwestAridRegion,Xi’anUniversityofTechnology,Xi’an 710048,China)
Abstract:Inordertobalanceandcompensatefortheadverseconsequencesofintermittentrenewableenergycon
nectedtothepowergridrandomly ,hydraulicturbinesareforcedtoexperienceincreasedloadreductionprocess,
whichinevitablyintroduceundesirablepressurefluctuationandvortexstructures.Basedonthepolyhedralmeshin
conjunctionwithdynamicmeshtechnology ,numericalsimulationswerecarriedouttoinvestigateparametersre
sponse,pressurefluctuationandvortexevolutiontowardsahigh - headFrancisturbineduringtheloadreductionby
closingtheguidevane.Thepresentedresultsconfirmthatthewaterheadobtainedfromnumericalsimulationisvali
datedwellagainstwithexperimentaldata ,andthepredicteddischargeishighlyreliable.Thevariationtrendof
pressuresignalinthevanelessinaccordancewiththeguidevanemovementandtheamplitudenearlykeepconstant
attheclosingstageofguidevane.However ,abruptchangeofpressureiscapturedinthedrafttubeattheinstants
whentheguidevanestartsandstopsclose ,andfinallyaremarkablepressurefluctuationwithperiodnatureis
formed.Unsteadypressurefluctuationgeneratedbyprecessingvortexropeisresponsiblefortheformationofaxial
thrustintherunner.Duringtheclosingofguidevane ,theaxisymmetricvortexropewithslightstrengthfirstlystret
chesalongbothaxialandradialdirections ,andthenshrinksaxially.Operatingatpartialload,thestraightandax
isymmetricvortexropefurthershortensandevolvesintoaslendervortexropewithtwinhelicalappearances.Subse
quently,thetwinvortexropemergesintoasinglehelicalstructurewithstrengthintensity,namelythehelicalvor
texropeinthedrafttubeatpartload.Inaddition,reductioninloadoftheturbinehasinducedsomesingularflow
conditionsincludingreversedflowandswirlflowinthedrafttube.
Keywords:Francisturbine;loadreduction;pressurefluctuation;axialthrust;vortexropeinthedrafttube
(责任编辑:王 婧)
(上接第 1368页)
Processanalysisofwettingdeformationtestofrockfillmaterials
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YINYin ,LIUYingfei,WUYongkang,ZHANGBingyin 2
(1.ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing 100038,China;
2.StateKeyLaboratoryofHydroscienceandEngineering,TsinghuaUniversity,Beijing 100084,China;
3.SchoolofCivilEngineering,BeijingJiaotongUniversity,Beijing 100044,China)
Abstract:Thewettingdeformationofrockfillmaterialisthemaincomponentofpost - constructiondeformationin
earth - rockfilldams.Duetothecreepcharacteristicsofrockfill ,itisusuallydifficulttodistinguishthewetting
deformationandcreepdeformationduringthewettingprocessofrockfill.Inthispaper,conventionaltriaxialtests
andtriaxialwettingtestswerecarriedoutusingtheweaklyweatheredgraniterockfillofNuozhaduhighearth - rock
filldam , toinvestigatethedeformationcharacteristicsofrockfillspecimensduringthewettingprocess.The
resultsshowthatinthetriaxialwettingtest ,thewater - fillingprocessofrockfillspecimenusuallylastsforacer
tainperiodoftime.Duringthisprocess,therockfillspecimenundergoesnotonlywetting - inducedinstantaneous
deformationbutalsoacertainamountofwet - statecreepdeformation.Thispaperpresentsaniterativemethodfor
analyzingthesaturatedwettingprocessofrockfill,whichcanseparateanddeterminethewet - statecreepdeforma
tionthatoccursduringspecimenwetting.Then ,usingthemodelparametersobtainedbytheiterativemethod,
quantitativeanalysisandwhole - processsimulationforthesaturatedwettingtestwerecarriedout.Thegoodfitting
effectverifiestherationalityandpracticabilityoftheproposedmethod.
Keywords:rockfillmaterial;wetting;creep;triaxialtest
(责任编辑:李 娜)
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