汽轮发电机组汽流激振基础问题及特性研究

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1、东南大学博士学位论文汽轮发电机组汽流激振基础问题及特性研究姓名：郭瑞申请学位级别：博士专业：动力机械及工程指导教师：杨建刚20090106AbstractUnderthedoublepressureofquickpowerdemandincreaseandenvironmentprotection，developingturbogeneratorunitwithlargecapacityandhighparameter,especiallysuperandultra-supercriticalunits，becomesthetrendofChinapowe

2、rindustry．Withtheincreaseofunitcapacityandsteamparameters，theinfluenceofsteamforceonrotorvibrationbecomesmoreandmoreimportant．Somerelevantfaultsoccurredinpowerplantrecently．Itbecomesoneofthemainfactorswhichinfluencethesafeoperationofunits．Researchontheoccurrencemechanismandprevent

3、ionmechanismofflowinducedvibrationarenecessaryandurgent．Theimprovementovertraditionaltwo··bulk--flowmodelandtheefficienttransfermethodtocalculatesealflowarepresentedinthepaper．Thepaperanalysesthethreedimensionalviscouscompressibleflowfieldsindetail．ThepaperpresentstheimprovedCFDmo

4、delingtechniquesandresearchestheinfluenceofpartialadmissiononflowinducedforcesthoroughly．Thepaperpresentsaneffectivenumericalmethodtopredictthestaticanddynamicperformancecharacteristicsofsealatoff-centerconditionswithdifferentrotorwhirlingfrequency．Modificationsareintroducedforthe

5、traditionalturbulentbulkflowmodeltoconsiderthecircumferentiallyvaryingflow．Atrigonometricseriesexpansionmethodisusedtoapproximateparameterssuchaspressureandvelocityinsealcavity．Numericalsimulationsshowthat8一10seriestermswith5—10iterationsisenoughforthesolutionofthissetofnonlineare

6、quations．neresultingnonlinearalgebraicequationscanbesolvedrapidly．VerificationoftheanalyticalresultsisobtainedbycomparisonwiththesimulatedCFDresults．Parametricinvestigationsshowingtheinfluenceofeccentricityandwhirlingfrequencyonsealdynamicsarealsopresented．Bothoftheeccentricityand

7、whirlingfrequencyareimportanttopredictsealdynamicsparameterscorrectly．Thetraditionalsealcalculationmodelissetuponthebaseofthetotalsealflowfield．Thecalculationtimeincreasesnonlinearlywiththeincreaseofsealteethnumber．Thepaperpresentsatransfermodelconsideringthefactthattherearemanyre

8、peatedcavitiesandteethinaseal．Asi