Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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CFD investigation of a JAEA 7-pin fuel assembly experiment with local blockage for SFR

  • Jeong, Jae-Ho (Department of Mechanical Engineering, Gachon University) ;
  • Song, Min-Seop (Department of Nuclear Engineering, Seoul National University)
  • Received : 2020.09.10
  • Accepted : 2021.05.09
  • Published : 2021.10.25
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Abstract

Three-dimensional structures of a vortical flow field and heat transfer characteristics in a partially blocked 7-pin fuel assembly mock-up of sodium-cooled fast reactor have been investigated through a numerical analysis using a commercial computational fluid dynamics code, ANSYS CFX. The simulation with the SST turbulence model agrees well with the experimental data of outlet and cladding wall temperatures. From the analysis on the limiting streamline at the wall, multi-scale vortexes developed in axial direction were found around the blockage. The vortex core has a high cladding wall temperature, and the attachment line has a low cladding wall temperature. The small-scale vortex structures significantly enhance the convective heat transfer because it increases the turbulent mixing and the turbulence kinetic energy. The large-scale vortex structures supply thermal energy near the heated cladding wall surface. It is expected that control of the vortex structures in the fuel assembly plays a significant role in the convective heat transfer enhancement. Furthermore, the blockage plate and grid spacer increase the pressure drop to about 36% compared to the bare case.

Keywords

Acknowledgement

The research paper is made possible through the encouragement and support from Dr. Hiroyuki Ohshima of JAEA. This study has been supported by National R&D Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (No.2020R1G1A1099560). This work was also supported by the Gachon University research fund of 2019 (GCU-2019-0797).

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