Experimental study of the influence of buoyancy on turbulent mixed convection in lead–bismuth eutectic flow under inclination conditions

Abstract

The effects of inclination conditions on the heat transfer characteristics of lead–bismuth eutectic in a vertical circular tube are investigated experimentally. The results show that, compared to the vertical flow, inclination conditions result in lower wall temperature, increased fluid temperature and higher local heat transfer intensity of LBE. The effects of inclination conditions on the heat transfer characteristics of LBE flow decrease with increasing Reynolds number. Mixed convection determination criterion Y divides the heat transfer region into mixed convection and forced convection zones. The threshold value is around 2.0 × 10-3. The inclination conditions enhance the heat transfer characteristics only under mixed convection when the natural convection due to buoyancy force is more significant compared to the forced convection. The effects of inclination conditions increase with Y and inclination angle and decrease with Peclet number. The heat transfer correlation for LBE vertical flow cannot predict the Nusselt number under inclination conditions well. Therefore, a relevant empirical correlation for inclination conditions is developed. The research would be helpful for the mechanism analysis and engineering design when liquid metals are applied for motion conditions.