High-accuracy CFD prediction methods for fluid and structure temperature fluctuations at T-junction for thermal fatigue evaluation

•Numerical methods for accurate prediction of thermal loading were proposed.•Predicted fluid temperature fluctuation (FTF) intensity is close to the experiment.•Predicted structure temperature fluctuation (STF) range is close to the experiment.•Predicted peak frequencies of FTF and STF also agree we...

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Veröffentlicht in:Nuclear engineering and design 2015-07, Vol.288, p.98-109
Hauptverfasser: Qian, Shaoxiang, Kanamaru, Shinichiro, Kasahara, Naoto
Format: Artikel
Sprache:eng
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Zusammenfassung:•Numerical methods for accurate prediction of thermal loading were proposed.•Predicted fluid temperature fluctuation (FTF) intensity is close to the experiment.•Predicted structure temperature fluctuation (STF) range is close to the experiment.•Predicted peak frequencies of FTF and STF also agree well with the experiment.•CFD results show the proposed numerical methods are of sufficiently high accuracy. Temperature fluctuations generated by the mixing of hot and cold fluids at a T-junction, which is widely used in nuclear power and process plants, can cause thermal fatigue failure. The conventional methods for evaluating thermal fatigue tend to provide insufficient accuracy, because they were developed based on limited experimental data and a simplified one-dimensional finite element analysis (FEA). CFD/FEA coupling analysis is expected as a useful tool for the more accurate evaluation of thermal fatigue. The present paper aims to verify the accuracy of proposed numerical methods of simulating fluid and structure temperature fluctuations at a T-junction for thermal fatigue evaluation. The dynamic Smagorinsky model (DSM) is used for large eddy simulation (LES) sub-grid scale (SGS) turbulence model, and a hybrid scheme (HS) is adopted for the calculation of convective terms in the governing equations. Also, heat transfer between fluid and structure is calculated directly through thermal conduction by creating a mesh with near wall resolution (NWR) by allocating grid points within the thermal boundary sub-layer. The simulation results show that the distribution of fluid temperature fluctuation intensity and the range of structure temperature fluctuation are remarkably close to the experimental results. Moreover, the peak frequencies of power spectrum density (PSD) of both fluid and structure temperature fluctuations also agree well with the experimental results. Therefore, the numerical methods used in the present paper are of sufficiently high accuracy to be suitable for the CFD prediction of highly fluctuating flow and temperature fields.
ISSN:0029-5493
1872-759X
DOI:10.1016/j.nucengdes.2015.04.006