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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