Themeasurementaccuracyofanultrasonicheatmeterdependsontherelationshipoftheprofile-linearaveragevelocity.Therearevariousmethodsforthecalculationofthelaminarandturbulenceflowregions,butfewmethodsforthetransitionregion.Atpresent,thetraditionalmethodtodealwiththetransitionregionistoadopttherelationshipfortheturbulentflowregion.Inthisarticle,asimplifiedmodelofthepipeisusedtostudythecharacteristicsofthetransitionflowwithspecificReynoldsnumber.Thek-εmodelandtheLargeEddySimulation(LES)modelare,respectively,usedtocalculatetheflowfieldofthetransitionregion,andacomparisonwiththeexperimentresultsshowsthattheLESmodelismoreeffectivethanthek-εmodel,itisalsoshownthattherewillbealargeerroriftherelationshipbasedontheturbulenceflowisusedtocalculatetheprofile-linearaveragevelocityrelationshipofthetransitionflow.Theprofile-linearaveragevelocityfortheReynoldsnumberrangingfrom5300to10000arecalculated,andtherelationshipcurveisobtained.Theresultsofthisarticlecanbeusedtoimprovethemeasurementaccuracyofultrasonicheatmeterandprovideatheoreticalbasisfortheresearchofthewholetransitionflow.
