Study on Flow and Heat Transfer of Liquid Gallium

Abstract

Reactor coolant is media that is used to cool the reactor core and carry the heat released by core. The selection of excellent coolant is beneficial to improve the safety performance of the reactor and reduce the size of the reactor, which is the key to develop a more compact small medium nuclear reactor. Gallium can be used as coolant due to its low melting point, high thermal conductivity and boiling point. In this paper, liquid gallium is selected as objective. The influence of inlet velocity, heat flux and tube diameter on heat transfer characteristics has been investigated using numerical simulation under different boundary conditions. Numerical results indicated that heat transfer coefficient of liquid gallium will increase with the increase of inlet velocity and will slightly increase with heat flux. Moreover, heat transfer coefficient will be enhanced by reducing the tube diameter. Finally, heat transfer coefficients of liquid gallium, water and lead-bismuth were also studied. The results show that liquid gallium has the best heat transfer coefficient, followed by lead-bismuth, and water has the worst heat transfer coefficient under the same boundary conditions. It is found that the application of gallium in the reactor coolant system is beneficial to the reduction of system size and the development of small medium reactors.