Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (9): 90603-090603.

• NUCLEAR ENERGY SCIENCE AND ENGINEERING •

### Turbulent heat transfer of liquid metal inside the sub-channels of reactor core

GE Zhihao PENG Yongsheng LYU Yijun DENG Weiping ZHAO Pinghui

1. (School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, China)
• Received:2015-02-02 Revised:2015-03-29 Online:2015-09-10 Published:2015-09-10

Abstract: Background: Liquid metal has been proposed as the coolant of the fourth generation nuclear reactor and the accelerator driven sub-critical system. Due to its low molecular Prandtl number (Pr), liquid metal differs from other coolants like water or gas in heat transfer. Purpose: This study aims to investigate the character of heat transfer of liquid metal inside the reactor core. Methods: Speziale-Sarkar-Gatski (SSG) Reynolds stress model was applied to the Computational Fluid Dynamics (CFD) prediction of liquid metal flow and heat transfer inside the sub-channels of the reactor core. Effect of different dimensionless parameters, e.g. Reynolds number (Re), Pr, Grashof number (Gr) and pitch-to-diameter ratio (P/D) on the turbulent heat transfer calculated results was investigated. Results: The dimensionless convective heat transfer coefficient (Nu), predicted by the CFD method, agrees well with the experimental data and the empirical relations. Conclusion: Based on the analysis of various dimensionless parameters, it is found that the heat exchange performs better in triangular fuel assembly sub-channels than that in square sub-channels, under the same condition of P/D and Re. The inhomogeneous circumferential distributions of temperature and heat transfer can be effectively improved by increasing Re and P/D or choosing coolants with large Pr. When Re is larger than 10000, the buoyancy effect on liquid metal heat transfer could be ignored.