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                            Analysisofenergylossesanditsmechanismsinacentrifugalimpeller
                                        basedonmeanflowkineticenergytransport

                                                      1
                                                                 1,2
                                       CHENWeisheng,LIYaojun ,LIUZhuqing        1,2
                         (1.CollegeofWaterResourcesandCivilEngineering,ChinaAgriculturalUniversity,Beijing 100083,China;
                         2.BeijingEngineeringResearchCenterofSafetyandEnergySavingTechnologyforWaterSupplyNetworkSystem,
                                                    Beijing 100083,China)


                  Abstract:Energylossesintheimpellerarethekeyfactorsaffectingthehydraulicperformanceofcentrifugalpump.
                  Inthispaper,theVeryLargeEddySimulation(VLES)turbulencemodelwhichdirectlyresolvesthelarge - scale
                  turbulencestructureisusedtonumericallysimulatetheinternalflowofalowspecificspeedcentrifugalimpellerat
                  threeflowrates(1.0Q d ,0.6Q d and0.25Q d ),aimtorevealthemeanflowkineticenergylosscharacteristicsinthe
                  impeller.Apowerlossanalysismethodbasedonthetransportofmeanflowkineticenergyisproposedandapplied
                  tostudytheinternalflowfeatures ,energylossesanditsmechanismoftheimpeller.Thenewlyproposedpowerloss
                  analysismodelcalculatesthedirectviscouslossesandtheturbulentenergyproductionbyintegratingthedirectvis
                  cousdissipationtermandtheturbulentkineticenergyproductiontermofthemeanflowkineticenergytransporte
                  quation ,establishesthecorrelationbetweenflowcharacteristicswithmeanflowkineticenergyloss,andobtainsthe
                  spatialdistributionofmeanflowkineticenergylossesintheflow.Theresultsshowthatthedirectviscouslossesof
                  theimpellerareconcentratedinthenear - wallregionanddecreasessignificantlywiththedecreaseofflowrate.The
                  strongsheareffectresultedbythecomplexflowstructureintheturbulentcoreregionoftheimpelleristhedirect
                  causefortransferofenergyfromthemeanflowtotheturbulentstructures.However ,differencesarefoundinthe
                  mechanismofturbulentkineticenergyproductionfordifferentflowstructures.Inthestrongshearflowregionformed
                                                                                                       ,
                  bythebladepressuresideseparationflow ,theturbulentkineticenergyproductionterm componentsP andP r θ
                                                                                               θθ
                  promotingenergytransportfromthemeanflowtotheturbulentstructure,increasingthecircumferentialandradial
                  componentsofturbulentkineticenergy ,whileP rr reducestheradialcomponentofturbulentkineticenergyandsup
                  pressesthemeankineticenergylosses.Fortheshearflowcausedbybladesuctionsideseparationflowsandinthe
                                        andP rr arethedominantfactorsforturbulentkineticenergyproduction,andP sup
                  impelleroutletbackflow ,P r θ
                                                                                                   θθ
                  pressesthegenerationofturbulentkineticenergy.
                  Keywords:centrifugalimpeller;meanflow kineticenergy;turbulentkineticenergy;energyloss;verylarge
                  eddysimulation

                                                                                    (责任编辑:王 婧)










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