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\xa0oxygen sensors. The analysis is performed on the 3-D cylindrical container, where the\xa0fluid in\xa0low Rayleigh number for the purpose of sensor calibration.\xa0The oxygen is supplied\xa0from the cover gas\xa0at the top of the container. Natural convection and oxygen transfer are examined\xa0under three temperature boundary\xa0conditions: (a)\xa0higher\xa0heated temperature in\xa0lower part and lower\xa0heated temperature\xa0in\xa0upper part of the sidewalls of the container; (b) higher\xa0heated temperature\xa0from the sidewalls and lower\xa0heated temperature\xa0from the top of the container; (c) higher\xa0heated temperature from one half side and lower\xa0heated temperature from the other. It is\xa0found that there are four, two and one convective circulation cells at the vertical section under conditions (a), (b), and (c), respectively. All\xa0these flows induced by the natural convection greatly enhance the oxygen transfer in the liquid metal. The most efficient\xa0one is under condition (b), it takes ~10 3 s for the oxygen concentration in the whole field to reach ~90%\xa0of the input oxygen concentration from the top, instead of ~10 6 \xa0s by the pure diffusion.