简介:Waveenergyhasdrawnmuchattentionasanachievablewaytoexploittherenewableenergy.Atpresent,inordertoenhancethewaveenergyextraction,mosteffortshavebeenconcentratedonoptimizingthewaveenergyconvertorandthepowertake-offsystemmechanicallyandelectrically.However,focusingthewavepowerinspecificwavefieldcouldalsobeanalternativetoimprovethewaveenergyextraction.Inthisexperimentalstudy,theBraggresonanceeffectisappliedtofocusthewaveenergy.BecausetheBraggresonanceeffectoftherippledbottomlargelyamplifiesthewavereflection,leadingtoasignificantincreaseofwavefocusing.Achievedwithanenergyconversionsystemconsistingofapointabsorberandapermanentmagnetsinglephaselinearmotor,thewaveenergyextractedinthewaveflumewithandwithoutBraggresonanceeffectwasmeasuredandcomparedquantitativelyinexperiment.ItshowsthatenergyextractionbyapointabsorberfromastandingwavefieldresultedfromBraggresonanceeffectcanberemarkablyincreasedcomparedwiththatfromapropagatingwavefield(withoutBraggresonanceeffect).
简介:ThefirstChineseexperimentalwavepowerplant,i.e.,theshoremountcdexperimentalwavepowerplantatthePearlRiverEstuarywassuccessfulintrialpowergenerationonFebruary15,1990.TheplantisonthesouthshoreoftheDawanshanIslandinthePearlRiverEstuary,facingthevastwavingSouthChinaSea.WithadesignedwaveconditionofH1/10=1.5mandT=6.5s,theplannedinstalledcapacityis8kWcomprisingthefirstunitof3kWbrushlessclawpolegeneratorwhichdelivers110VDCcurrentandthesecondunitof5kWbrushlesssinglephasesynchroACgeneratorwhichdelivers220VACcurrent.Atpresent,thefirstunithasbeenputintotrialoperation.
简介:MarmaraSea,locatedbetweenBlackSeaandAegeanSea,isanimportantseaforoceanengineeringactivities.Inthisstudy,wavepowerpotentialofMarmaraSeawasinvestigatedusingthethirdgenerationspectralwind-wavemodelMIKE21SWwithunstructuredmesh.WinddatawasobtainedfromECMWFERA-Interimre-analyseswinddatasetat10mwithaspatialresolutionof0.1?fortheperiodof1994to2014.ThenumericalmodelwascalibratedwithmeasuredwavedatafromabuoystationlocatedinMarmaraSea.Meshoptimizationwasalsoperformedtoobtainthemostsuitablemeshstructureforthestudyarea.ThisstudyisthefirstthatdealtwiththedeterminationofwaveenergypotentialofMarmaraSea.Thenumericalmodelresultsarepresentedintermsofmonthly,seasonalandannualaverageofwavepowerflux(kWm-1).Themaximumwavepowerfluxis1.13kWm-1andoccursinNovember.Theoverallannualmeanwavepowerfluxduring1994–2014isfoundtobe0.27kWm-1intheoffshoreregions.
简介:Withtheglobalwarmingandsealevelrising,itiswidelyrecognizedthatthereisanincreasingtendencyoftyphoonoccurrencefrequencyandintensity.Thedefensescodeagainsttyphoonattacksfornuclearpowerplantshouldbecalibratedbecauseoftheincreasingthreatoftyphoondisasterandsevereconsequences.Thispaperdiscussestheprobabilisticapproachofdefinitionsabout'probablemaximumtyphoon'and'probablemaximumstormsurge'innuclearsafetyregulationsofChinaandhasmadesomedesigncodecalibrationsbyuseofanewlyproposedDoubleLayerNestedMulti-objectiveProbabilityModel(DLNMPM).
简介:Pointabsorberwaveenergydevicewithmultipledegreesoffreedom(DOF)isassumedtohaveabetterabsorptionabilityofmechanicalenergyfromoceanwaves.Inthispaper,acoaxialsymmetricarticulatedpointabsorberwaveenergyconverterwithtwodegreesoffreedomispresented.Themechanicalequationsoftheoscillationbuoywithpowertake-offmechanism(PTO)inregularwavesareestablished.Thethree-dimensionalnumericalwavetankisbuiltinconsiderationofthebuoymotionbasedupontheCFDmethod.Theappropriatesimulationelementsareselectedforthebuoyandwaveparameters.ThefeasibilityoftheCFDmethodisverifiedthroughthecontrastbetweenthenumericalsimulationresultsoftypicalwaveconditionsandtestresults.Insuchcase,thebuoywithsingleDOFofheave,pitchandtheircouplingmotionconsideringfree(noPTOdamping)anddampedoscillationsinregularwavesaresimulatedbyusingtheverifiedCFDmethodrespectively.Thehydrodynamicandwaveenergyconversioncharacteristicswithtypicalwaveconditionsareanalyzed.Thenumericalresultsshowthattheheaveandpitchcanaffecteachotherinthebuoycouplingmotion,hydrodynamicloads,waveenergyabsorptionandflowfield.ThetotalcapturewidthratiowithtwocoupledDOFmotionishigherthanthatwithasingleDOFmotion.ThewaveenergyconversionofacertainDOFmotionmaybehigherthanthatofthesinglecertainDOFmotioneventhoughthewaveisattheresonanceperiod.Whenthewaveperiodsarehighenough,theinteractionbetweenthecoupledDOFmotionscanbeneglected.
简介:Thispaperpresentsanextendedmodelpredictivecontrollerformaximizingtheabsorbedpowerofapointabsorberwaveenergyconverter.Owingtothegreatinfluenceofcontrollerparametersupontheabsorbedpower,theoptimizationoftheseparametersiscarriedoutforthefirsttimebyafireflyalgorithm(FA).Error,thedifferencebetweenoutputvelocityofbuoyandinputwavespeedwhichleadstopowermaximizationintheoptimizedMPCiscomparedwiththeclassicalMPC.Simulationresultsindicatethatgiventhehighaccuracyandacceptablespeedofthealgorithm,itcanadjusttheparametersofthecontrollertothepointwheresystemerrordecreasedeffectivelyandtheabsorbedenergyincreasedabout4MW.
简介:Onthebasisofthedataofbiologicalandnonbiologicalfactorscollectedrespectivelyfrom1989to1990andfrom1995to1996inthewatersnearbytheQinshanNuclearPowerStation,theecologicalenvironmentandwaterqualityofthewatersareanalyzedandassessedinthepaper.Theresultsshow:(a)thesurveyedareahasthetypicalecologicalcharacteristicsofhightidalrangeestuary,richnutrientsandlowbiologicalproductivity,(b)tide,runoffandoffshoreseawaterintrusionarethekeyfactorswhichresultinseasonalandannualchangesofvariousbiologicalandnon-biologicalfactors,(c)theriskingofseawatereutrophicationindexisresultedfromenormousamountofthedischargesofindustrialanddomesticsewage,(d)becausethesurveyareaislocatedinahightidal-rangeestuary,thermaleffluentfromcoolingsystemdoesnotinducesignificanttemperaturechanges,(e)thefirststageprojectofQinshannuclearpowerstationhasnonotableimpactsontheecologicalenvironmentinthe