600MW超临界机组汽动锅炉给水泵水动力及临界转速的分析与计算的综述报告

600MW超临界机组汽动锅炉给水泵水动力及临界转速的分析与计算的综述报告AbstractInthisreport,thewaterdynamicsandcriticalspeedanalysisandcalculationforthe600MWultra-supercriticalunitsteamboilerfeedpumparereviewed.First,thebasicprinciplesandparametersofthesteamboilerfeedpumpsystemareintroduced.Next,thecalculationmethodandformulaforcalculatingthecriticalspeedofthefeedpumprotorarediscussedindetail.Theimportanceofwaterdynamicsinthesystemisdiscussed,andthefactorsaffectingwaterresistanceareanalyzed.Finally,thereportdiscussesthemeasuresthatcanbetakentoreducewaterresistanceandpreventcriticalspeedsfromoccurringinthesystem.IntroductionThesteamboilerfeedpumpisanimportantcomponentinapowerplant,responsibleforprovidinghigh-pressurewatertothesteamboiler.Thewaterdynamicsandcriticalspeedofthefeedpumpsystemareimportantfactorsthatneedtobeconsideredduringthedesignandoperationoftheplant.The600MWultra-supercriticalunitsteamboilerfeedpumpisacomplexsystem.Ifthepumprotoroperatesataspeedclosetoitscriticalspeed,itmaycausevibrationanddamagetothepump.Therefore,itisnecessarytoanalyzethewaterdynamicsandcriticalspeedofthefeedpumpsystemandtakeeffectivemeasurestopreventpotentialproblems.BasicprinciplesandparametersofsteamboilerfeedpumpThesteamboilerfeedpumpsystemisdesignedtoprovidehigh-pressurewatertothesteamboiler.Thesystemconsistsofthefeedpump,theturbine,andthecondenser.Thefeedpumpisdrivenbyasteamturbine,whichispoweredbythesteamgeneratedbytheboiler.Thehigh-pressurewaterispumpedfromthefeedwatertanktothesteamgenerator,whereitisheatedtoproducesteam.Thesteamisthenusedtodrivetheturbineandgenerateelectricity.Theparametersofthefeedpumpsystemincludetheflowrate,pressure,andspeedofthewater.Theflowrateofthewaterisdeterminedbythepoweroutputoftheplantandthespecificenergyconsumptionofthefeedpump.Thepressureofthewaterisdeterminedbythepressureofthesteamintheboilerandthepressuredropinthefeedpump.Thespeedofthepumprotorisanimportantfactorthataffectsthewaterdynamicsandcriticalspeedofthesystem.CalculationmethodandformulaforcriticalspeedThecriticalspeedofthefeedpumprotoristhespeedatwhichthepumpexperiencesresonanceandsignificantvibration.Tocalculatethecriticalspeedofthepumprotor,thefollowingformulacanbeused:f=(n/60)×[k/(πD)²]½Where:f=criticalspeedn=rotationalspeed(revolutionsperminute)k=torsionalstiffnesscoefficientD=diameteroftherotorThetorsionalstiffnesscoefficientiscalculatedasfollows:k=EJ/LWhere:E=modulusofelasticityJ=polarmomentofinertiaL=lengthoftherotorThepolarmomentofinertiaforasolidcylindricalrotorisgivenby:J=(π/2)×[(D/2)⁴-(d/2)⁴]Where:d=diameteroftherotorshaftWaterdynamicsinthefeedpumpsystemWaterresistanceisanimportantfactorintheperformanceofthefeedpumpsystem.Thefactorsthataffectwaterresistanceincludethediameterandlengthofthepumppiping,thevalvesettings,thestructuraldesignofthepipesurfaces,andthespeedofthepumprotor.Theforceexertedbythewaterflowinginthesystemiscalledhydrodynamicforce.Thewaterdynamicsinthesystemcanbeanalyzedusingcomputationalfluiddynamics(CFD)software.CFDsimulationscanbeusedtopredicttheflowofthewaterinthesystemandidentifypotentialareasofhighresistance.TheresistanceofeachsectionofthepipingcanbecalculatedusingtheDarcy-Weisbachequation.MeasurestoreducewaterresistanceandpreventcriticalspeedsToreducewaterresistanceinthefeedpumpsystem,thefollowingmeasurescanbetaken:-Increasethediameterofthepipingtoreducewaterresistance.-Improvethestructuraldesignofthepipesurfacestoreducefrictionandincreasetheefficiencyofthesystem.-Usemoreefficientpumpswithimprovedimpellerdesignstoreducewaterresistance.-Keeptheturbineandpumpingoodconditiontoavoidexcessivevibrationanddamagetothesystem.Topreventcriticalspeedsfromoccurringinthesystem,thefollowingmeasurescanbetaken:-Reducetherotationalspeedofthepumptoavoidoperatingatcriticalspeeds.-Usevibrationmonitoringsystemstodetectchangesinthevibrationpatternsofthesystem.-Usevibrationdamperstoreducetheamplitudeofvibrationsandpreventdamagetothesystem.-Increasethestiffnessofthesystemtoreducethelikelihoodofresonanceandcriticalspeeds.ConclusionThewaterdynamicsandcriticalspeedofthe600MWultra-supercriticalunitsteamboilerfeedpumpsystemareimportantfactorsthatneedtobeconsideredduringthedesignandoperationoftheplant.Properdesignandmaintenanceofthesystem,includingtheuseofefficientpump