Thermal mixing in a T-junction

Authors: Westin et al.

Type: Experimental

Status: tip

Contents

Description

Flow Parameters

Reference Publications

Results

Description

The main pipelines in Pressurized Water Reactors can age prematurely as result of fluctuating thermal thermal stress in the vicinity of T junctions where cold water flowing in one pipe meets hot water flowing in another. Leaks due to thermal fatigue have already been observed in PWR throughout the world; USA, Germany, Japan, Belgium, France, leading to partial or complete stoppage of the reactor. There are a number of projects currently underway to numerically study this sort of thermal fatigue. However there remain a number of difficulties principally related to turbulence modelling and the coupling between the turbulence and the heat flux. Several Experiments have recently produced reliable data in the core of the flow (Westin et al. 2008) or at the pipe walls (Pasutto et al. 2007). The Ogawa et al. experiment contains detailed temperature and velocity measurements, but for a smaller secondary pipe.

Flow Parameters

The tests were carried out with a constant flow ratio Q2/Q1=2, which implies approximately equal flow velocities in the two inlet pipes. The temperature difference between the hot and cold water was 15°C, and the Reynolds number in both inlet pipes were approximately 10^5 for the test case considered in the paper with bulk velocities of approximately 0.8 m/s.


Additional information (links, pictures, etc.)

Snapshots of instantaneous temperature distribution from different T-junction configurations (see references cited above)

Tjunction2.png

streamlines_anim2.gif

iso_q_and_temp.gif

  • watlon.tar.gz: watlon.tar.gz. These are the results presented in Pasutto T. et al. [2]. The file includes exp. data for comparison.
  • DiscussCase016

  • TGRID.tar.gz: The Grid used for the LES run in unv format. The additional files contain the inlet profiles and README file for details.

Reference Publications

  1. Westin J., Veber P., Andersson L., Mannetje C., Andersson U., Eriksson J., Hendriksson M., Alavyoon F., Andersson C.: “High-Cycle Thermal Fatigue in Mixing Tees. Large-Eddy Simulations Compared to a New Validation Experiment”, 16th Int. Conf. On Nuclear Engineering (ICONE-16), Florida, Orlando, USA, 11-15 May 2008, Paper No. 48731, pp. 1-11. Westin_J_2008_ICONE16_48731l.pdf
  2. Pasutto T., Peniguel C., Stefan, Effects of the upstream elbows fort hermal fatigues in PWR T Junctions using LES. Paper 10410, ICONE 15 , Nagoya, Japan, paper April 22-26, 2007 Pasutto_etal_2007_ICONE-15-10410_EDF.pdf
  3. Dahlberg, Nilsson, Taylor, Faidy, Wilke, Chapuliot, Kalkhof, Bretherton, Church, Solin, Catalano, 2007, Development of a European Procedure for Assessment of High Cycle Thermal Fatigue in Light Water reactors: Final report of the NESC-Thermal Fatigue project, European Commission, Joint Research Centre, EUR22763EN .
  4. Faidy, Chapuliot, April, 2008, Summary of recent and on-going Fatigue programs through NULIFE organizations and consequences for EC procedure, NULIFE. EU network on Nuclear power plant prediction: http://www.vtt.fi/proj/nulife/index.jsp
  5. Westin J., Alavyoon F., L. Andersson, P. Veber Experiments and Unsteady CFD-calculations of the Thermal mixing in a T-Junction; Workshop on Benchmarking of CFD Codes for Application to Nuclear Reactor Safety (CFD4NRS ), IAEA & GRS Garching, Munich, 5 - 7 Septembre 2006 http://www.nea.fr/html/nsd/reports/2007/nea6298/Technical_Session_A5_Mixing_In_Primary_Circuit/
  6. Péniguel, C., Sakiz, M., Benhamadouche, S., Stephan, J.-M. and Vindeirinho, C. (2003),Presentation of a numerical 3D approach to tackle thermal striping in a PWR nuclear T-junction, PVP/DA007, Proceedings of ASME PVP, July 20-24, 2003, Cleveland, USA.
  7. Zboray R., Manera A., Niceno B., Prasser H.-M.: “Investigations on Mixing Phenomena in Single-phase Flows in a T-Junction Geometry”, NURETH-12, Paper No. 71, pp. 1-20., Pittsburgh, U.S.A. September 2007,
  8. Ohtsuka, M., Kawamura, T, Fukuda, T., Moriya, S., Shiina, K., Kurosaki, M., Minami, Y. and Madarame, H. (2003) LES analysis of fluid temperature fluctuations in a mixing Tee pipe with the same diameters, ICONE 11-36064, 11th International Conference on Nuclear Engineering, Tokyo, Japan, April 20-23, 2003. 1 Braillard, O., Jarny, Y. and Balmigere, G. (2005) Thermal load determination in the mixing Tee impacted by a turbulent flow generated by two fluids at large gap of temperature, ICONE13-50361, 13th International Conference on Nuclear Engineering, Beijing, China, May 16-20, 2005.
  9. Frank Th., Adlakha M., C. Lifante C., H.-M. Prasser, F. Menter. Simulation of turbulent and thermal mixing in T-junctions using URANS and Scale-resolving turbulence models in ANSYS-CFX. Experiments and CFD Code Applications to Nuclear Reactor Safety (XCFD4NRS ) OECD/NEA CEA Workshop, Grenoble, France 10 - 12 Septembre 2008 Frank_et_al_2008_XCFD4NRS.pdf
  10. Ogawa H, Igarashi M, Nobuyuki Kimura N, Kamide H; EXPERIMENTAL STUDY ON FLUID MIXING PHENOMENA IN T-PIPE JUNCTION WITH UPSTREAM, International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-11), Log Number: 448,Avignon, France, October 2-6, 2005. Ogawa_2005_NURETH11_448.pdf

Results

Simulation results available for this case:
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Topic attachments
I Attachment Action Size Date Who Comment
elsegz TGRID.tar.gz manage 103339.7 K 2010-01-01 - 12:30 YacineAddad The Grid used for the LES run
gifgif iso_q_and_temp.gif manage 2229.3 K 2010-01-01 - 12:16 YacineAddad iso_q values
gifgif streamlines_anim2.gif manage 398.6 K 2009-12-30 - 11:13 YacineAddad T-junction image
elsegz watlon.tar.gz manage 78486.2 K 2009-02-23 - 12:06 YacineAddad  
Topic revision: r9 - 2010-01-01 - 12:32:36 - YacineAddad
 

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