Natural Convection and Oxygen Transfer of Liquid Lead-bismuth Eutectic in Cylindrical Container

Abstract

The present study carries out numerical analysis of the coupled natural convection and oxygen transfer of liquid lead-bismuth eutectic (LBE) for calibrating low concentration level oxygen sensors. The analysis is performed on the 3-D cylindrical container, where the fluid in low Rayleigh number for the purpose of sensor calibration. The oxygen is supplied from the cover gas at the top of the container. Natural convection and oxygen transfer are examined under three temperature boundary conditions: (a) higher heated temperature in lower part and lower heated temperature in upper part of the sidewalls of the container; (b) higher heated temperature from the sidewalls and lower heated temperature from the top of the container; (c) higher heated temperature from one half side and lower heated temperature from the other. It is found that there are four, two and one convective circulation cells at the vertical section under conditions (a), (b), and (c), respectively. All these flows induced by the natural convection greatly enhance the oxygen transfer in the liquid metal. The most efficient one is under condition (b), it takes ~10 3 s for the oxygen concentration in the whole field to reach ~90% of the input oxygen concentration from the top, instead of ~10 6 s by the pure diffusion.