Page 47 - 2023年第54卷第7期
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experiments.Thestudy’sfindingsdemonstratethatalargeincidenceanglecausesastrongflowseparationphenom
                  enonneartherunnerinlet,whichcreatesamassivevortexstructureintherunnerbladepassage.Withtheincrease
                  oftherotatingspeed ,thevolumeofthevortexstructureincreasesgradually,andthevortexstructuredisturbsthe
                  mainflowstrongly.Thelow - frequencyandhigh - amplitudepressurefluctuationswithbroadbandcharacteristicsare
                  capturedbynumericalcalculation ,anditsfrequencyrangeisbelow0.5timesthebladepassingfrequency.Be
                  sides,thecorrespondingpressureamplitudeoftherunnerregionisthehighest.Theenergydissipationcharacteris
                  ticsoftheturbinearefurtheranalyzedonthebasisofenergybalanceequation,anditisfoundthattheenergydissi
                  pationofeachflowpassagecomponentmainlyoccursintheinitialstageoftheriseofthespeed,andthesumofthe
                  energydissipationintherunnerandthedrafttubeexceeds90% ofthetotalenergydissipation.Additionally ,turbu
                  lencedominatesenergytransportanddissipationintheunstablerunawayprocess,asshownbythefactthatthetur
                  bulentkineticenergygenerationtermandtheReynoldsstressworktermaremuchlargerthantheviscousdissipation
                  termandtheviscousforceworkterm.Besides ,thelocationofthemainenergydissipationinthewheelcoincides
                  withthelocationofthevortexduringrotation ,suggestingthattheintricatevortexstructureinthewheelisthe
                  sourceofenergydissipation.Itpointsoutthedirectionforfurtherstudyontheenergydissipationmechanismofthe
                  turbinetransientrunawayprocess.
                  Keywords:Francisturbine;runawayprocess;transientflow;vortex;energydissipation

                                                                                    (责任编辑:王 婧)


              (上接第 793页)
                    Turnovercharacteristicsanddissolvedoxygenresponsesinalargestratifiedreservoir
                                                           1
                                                                                      1
                                                                       1
                               1,2
                                              1,3
                    DUYanliang ,LIUXiaowei ,LIUXiaobo,LIUChang,WANGShiyan,ZHAOShilin                1
                (1.DepartmentofWaterEcologyandEnvironment,ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing 100038,China;
                   2.ShanghaiEngineeringResearchCenterofWaterEnvironmentSimulationandEcologicalRestoration,Shanghai 200233,China;
                                      3.ChangchunInstituteofTechnology,Changchun 130000,China)
                  Abstract:Turnoverhasimportanteco -significancetothestratified reservoirs.Byin -situ monitoringin
                  PanjiakouReservoir,alargeanddeepreservoirinnorthernChina,associatedwithavertical2 - dimensionalhy
                  drodynamic - waterquality - waterecologicalmodel,thereservoirturningcharacteristicsanddissolvedoxygen
                  (DO)responsewerestudied.Theenvironmentalevolutionprocessesin2018and2020aremodelledrespectively,
                  andtheresultsshowthatwatertemperaturestratificationleadstoverticalstratificationofdissolvedoxygen(DO).
                  ThesurfaceDOhasacorrelationwiththeairtemperature,andthebottomDOcontinuestodropto0afterstratifi
                  cation.Theautumnturnoveristheprincipalwayofthebottomaerationannually.Theaverageoperatingwaterlev
                  elin2018was14.2mhigherthanthatin2020,andthemaximumthicknessoftheepilimnionin2018isnearly
                  10mgreaterthanthatin2020.Thereservoirturnoversstartedfromthetailofthereservoirtotheregioninfrontof
                  thedam.Thedurationofturnoverin2018was40daysshorterthanthatin2020intheanalyzeddomainwhichis
                  about30kmfromthetailtothedam.TheverticalmixingtimeofDOlagsbehindthewatertemperatureby7to10
                  days.SurfaceDOwasstronglyinfluencedbytheturnoveranddropped3 - 4mg?Lintheperiodwiththerelatively
                  lowwaterlevelin2020.Theannualavailablepotentialenergyindex (APE)ofeachsectionwasutilizetoanalyze
                  thestabilityofstratification.Whenthewaterlevelofthereservoirislow ,theDOofthesurfacewaterbodypro
                  ducedbythereservoirturnoverwilldropmore ,withadropof3 - 4mg?L.Theannualvariationprocessofthea
                  vailablepotentialenergyindex (APE)ofdifferentsectionsofthereservoirisanalyzedrespectively.Thedatesof
                  turnoverofdifferentlocationsinthetwoyearshaveagoodcorrelationwiththeaverageAPEindexinthesummer
                  mixingcycles.Thestudyexploredtheregularpatternofwaterenvironmentalevolutioninthedeepandstratified
                  reservoirs ,adminandsometheoreticalresultsforoptimaloperation.
                  Keywords:stratifiedreservoir;turnoverofwatertemperatureanddissolvedoxygen;turnoverdate;available
                  potentialenergyindex (APE);CE - QUAL - W2

                                                                                    (责任编辑:耿庆斋)



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