Investigation on the thermal mixing enhancement in a T-junction pipe

  • Mohamad Hamed HekmatEmail author
  • Saleh Saharkhiz
  • Ehsan Izadpanah
Technical Paper


In this paper, three-dimensional numerical simulations are conducted to study the thermal mixing of turbulent flow in a T-junction with hot fluid flowing in the main pipe and cold fluid in the branch. The main objective is to investigate the effects of the axial and cross-injection angles to the main pipe and the branch-to-main flow rate ratio on the turbulent thermal mixing. In this regard, an appropriate mixing index is proposed to evaluate the thermal mixing efficiency. The turbulence model employed in this research is the SST k-ω model that can properly capture the mixing behavior of the flow in the main pipe. The results show that the cross-injection angle can considerably affect the thermal mixing enhancement. However, the effects of injection angles on the thermal mixing at lower flow rate ratios are more significant.


T-junction Injection angles Flow rate ratio Thermal mixing Mixing index 



  1. 1.
    Zboraya R, Prasser H-M (2011) On the relevance of low side flows for thermal loads in T-junctions. Nucl Eng Des 241:2881–2888CrossRefGoogle Scholar
  2. 2.
    Taheri T (2007) Some advances on understanding of high cycle thermal fatigue crazing. J Press Vessel Technol 129(3):400–410MathSciNetCrossRefGoogle Scholar
  3. 3.
    Chung GY, Ferng YM (2018) Investigating effects of injection angles and velocity ratios on thermal-hydraulic behavior and thermal striping in a T-junction. Int J Therm Sci 126:74–81CrossRefGoogle Scholar
  4. 4.
    Hosseini SM, Yuki K, Hashizume H (2008) Classification of turbulent jets in a T-junction area with a 90-deg bend upstream. Int J Heat Mass Transf 51:2444–2454CrossRefGoogle Scholar
  5. 5.
    Hirota M, Kuroki M, Nakayama H, Asano H, Hirayama S (2008) Promotion of turbulent thermal mixing of hot and cold airflows in T-junction. Flow Turbul Combust 81(1–2):321–336CrossRefGoogle Scholar
  6. 6.
    Gao K, Wang P, Lu T, Song T (2015) Experimental investigation and numerical simulation for weakening the thermal fluctuations in a T-junction. Ann Nucl Energy 78:180–187CrossRefGoogle Scholar
  7. 7.
    Lin GH, Chen MS, Ferng YM (2016) Investigating thermal mixing and reverse flow characteristics in a T-junction by way of experiments. Appl Therm Eng 99(25):1171–1182CrossRefGoogle Scholar
  8. 8.
    Zhou M, Kulenovic R, Laurien E (2018) Experimental investigation on the thermal mixing characteristics at a 90° T-Junction with varied temperature differences. Appl Therm Eng 128:1359–1371CrossRefGoogle Scholar
  9. 9.
    Zhou M, Kulenovic R, Laurien E (2018) T-junction experiment with high temperature and high pressure to investigate flow rate influence on mixing characteristics. Int J Heat Fluid Flow 71:451–459CrossRefGoogle Scholar
  10. 10.
    Xu B, Wong TN, Nguyen N-T (2011) Experimental and numerical investigation of thermal chaotic mixing in a T-shaped microchannel. Heat Mass Transf 47:1331–1339CrossRefGoogle Scholar
  11. 11.
    Kickhofel J, Prasser H-M, Selvam PK, Laurien E, Kulenovic R (2016) T-junction cross-flow mixing with thermally driven density stratification. Nucl Eng Des 309:23–39CrossRefGoogle Scholar
  12. 12.
    Selvam PK, Kulenovic R, Laurien E, Kickhofel J, Prasser H-M (2017) Thermal mixing of flows in horizontal T-junctions with low branch velocities. Nucl Eng Des 322:32–54CrossRefGoogle Scholar
  13. 13.
    Chuang GY, Ferng YM (2017) Experimentally investigating the thermal mixing and thermal stripping characteristics in a T-junction. Appl Therm Eng 113:1585–1595CrossRefGoogle Scholar
  14. 14.
    Frank Th, Lifante C, Prasser HM, Menter F (2010) Simulation of turbulent and thermal mixing in T-junctions using URANS and scale- resolving turbulence models in ANSYS CFX. Nucl Eng Des 240:2313–2328CrossRefGoogle Scholar
  15. 15.
    Walker C, Manera A, Niceno B, Simiano M, Prassera H-M (2010) Steady-state RANS-simulations of the mixing in a T-junction. Nucl Eng Des 240:2107–2115CrossRefGoogle Scholar
  16. 16.
    Ebrahimi S, Hasanzadeh-Barforoushi A, Nejat A, Kowsary F (2014) Numerical study of mixing and heat transfer in mixed electroosmotic/pressure driven flow through T-shaped microchannels. Int J Heat Mass Transf 75:565–580CrossRefGoogle Scholar
  17. 17.
    Georgiou M, Papalexandris MV (2017) Turbulent mixing in T-junctions: the role of the temperature as an active scalar. Int J Heat Mass Transf 115:793–809CrossRefGoogle Scholar
  18. 18.
    Lin GH, Ferng YM (2016) Investigating thermal mixing and reverse flow characteristics in a T-junction using CFD methodology. Appl Therm Eng 102:733–741CrossRefGoogle Scholar
  19. 19.
    Krumbein B, Termini V, Jakirlić S, Tropea C (2018) Flow and heat transfer in cross-stream type T-junctions: a computational study. Int J Heat Fluid Flow 71:179–188CrossRefGoogle Scholar
  20. 20.
    Hattori H, Wase MI, Houra T, Tagawa M (2014) DNS and LES for turbulent heat transfer and mixing in T-junction channel flow. In: 10th International ERCOFTAC symposium on engineering turbulence modelling and measurements, SpainGoogle Scholar
  21. 21.
    Boatemaa A (2013) Effects of injection pipe orientation on mixing behavior in contributing to thermal fatigue in a T-junction of a pipe. Ph.D. thesis, University of GhanaGoogle Scholar
  22. 22.
    Höhne T (2014) Scale resolved simulations of the OECD/NEA–Vattenfall T-junction benchmark. Nucl Eng Des 269:149–154CrossRefGoogle Scholar
  23. 23.
    Gritskevich M, Garbaruk A, Frank T, Menter F (2014) Investigation of the thermal mixing in a T-junction flow with different SRS approaches. Nucl Eng Des 279:83–90CrossRefGoogle Scholar
  24. 24.
    Gritskevich MS, Garbaruk AV (2017) Influence of upstream pipe bends on the turbulent heat and mass transfer in T-junctions. J Phys: Conf Ser 891:012046Google Scholar
  25. 25.
    Saidi F, Aounallah M, Belkadi M, Adjlout L, Imine O (2015) Numerical simulation of turbulent thermal fluid in tee water duct cooled nuclear reactor. Appl Mech Mater 789–790:484–488CrossRefGoogle Scholar
  26. 26.
    De Santis A, Shams A (2018) Assessment of different URANS models for the prediction of the unsteady thermal mixing in a T-junction. Ann Nucl Energy 121:501–512CrossRefGoogle Scholar
  27. 27.
    Wang M, Fang D, Xiang Y, Fei Y, Wang Y, Ren W, Tian W, Su GH, Qiu S (2018) Study on the coolant mixing phenomenon in a 45° T junction based on the thermal-mechanical coupling method. Appl Therm Eng 144:600–613CrossRefGoogle Scholar
  28. 28.
    Menter FR (1994) Two-equation eddy-viscosity turbulence models for engineering applications. AIAA Journal 32:1598–1605CrossRefGoogle Scholar
  29. 29.
    Cebeci T (2004) Turbulence models and their applications; efficient numerical methods with computer programs. Springer, BerlinzbMATHGoogle Scholar
  30. 30.
    Lina M, Xua X, Wua B, Wangb L, Wang Q (2015) Numerical simulation of turbulent flow on a high-speed cross flow blowing over array slots with weak injection. Energy Procedia 75:1734–1739CrossRefGoogle Scholar
  31. 31.
    OpenFOAM (2016) The open source CFD toolbox, user guide v1612 + Google Scholar
  32. 32.
    GridPro (2017) Software package, ver. 6.6, Program Development Corp, White PlainsGoogle Scholar
  33. 33.
    ASME V&V 20 (2009) Standard for verification and validation in computational fluid dynamics and heat transfer. The American Society of Mechanical Engineering, USAGoogle Scholar
  34. 34.
    Zhou YP, Hao PF, Zhang XW, He F (2016) Numerical investigations of thermal mixing performance of a hot gas mixing structure in high-temperature gas-cooled reactor. Nucl Sci Tech 27:23CrossRefGoogle Scholar
  35. 35.
    Kok B, Uyar M, Varol Y, Koca A, Oztop HF (2013) Analyzing of thermal mixing phenomena in a rectangular channel with twin jets by using artificial neural network. Nucl Eng Des 265:554–565CrossRefGoogle Scholar
  36. 36.
    Kok B, Firat M, Oztop HF, Varol Y (2013) A numerical study on thermal mixing in narrow channels inserted rectangular bodies. Int Commun Heat Mass Transfer 44:69–76CrossRefGoogle Scholar

Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringTafresh UniversityTafreshIran
  2. 2.Department of Mechanical EngineeringPersian Gulf UniversityBushehrIran

Personalised recommendations