Research On Thermal Fluctuation Of Fluid Flow And Heat Transfer For Branch Pipe With/without Leakage In T-junction

In the piping systems, such as petrochemical industry and powerstations, and so on, T-junction is a very extensive use of the pipelinestructure. Fatigue thermal stress often happens in T-junctions due tothermal fluctuations of flow field, further generating thermal fatiguefailure, which results in major accidents and economic loss. In recentdecades, a lot of accident about pipeline leakage often happened due tothermal failure caused by the thermal fluctuations in nuclear plants,which attracts great attentions to thermal fatigue within T-junctions.In the research, Large Eddy Simulation turbulent model has beenused to flow field distribution with/without leakage for T-junctions.Firstly, instantaneous temperature and velocity fields without leakage inT-junction were obtained by Large Eddy Simulation. Then, simulationresults were compared with experiment results and found that they hadgood agreements, which verified the accuracy and reliability of LargeEddy Simulation and laid the solid theoretical foundation for flow andheat transfer with/without leakage in T-junction by Large Eddy Simulation.Based on validity test between simulation results and experimentresults, thermal fluctuations of flow fields of branch pipes for bent andstraight pipes with/without leakage were studied and flow fielddistributions in T-junction were also obtained. The research resultsshowed that swirl phenomenon occurred in branch pipe close to the maineither with or without leakage, as well as much difference in flow fieldswith/without leakage, different leakage in T-junction and differentstructure of T-junction, and so on.It is great importance for petrochemical industry and power stationsto research the thermal fatigue. It will be helpful to assess the safetymanagement and life cycle for plants, and for the prevention of thermalfatigue and optimization of pipeline design by predicting and evaluatingthermal fatigue for pipeline, which will be helpful to take effectivemeasures to avoid major accidents before thermal fatigue failure.Therefore, the key to safe operation for nuclear stations is the real-timedetection,prediction and assessment for nuclear power pipeline, so theresearch for the subject is of great scientific and practical significances.