Turbulent Characteristics in Lead-Bismuth Flows Flowing in Poor and Good Wettability Pipes

Lead-bismuth single-phase and two-phase upward flows in a round tube were measured by using an electro-magnetic probe and an electrical conductivity probe. Experiments were performed under adiabatic conditions by varying the superficial gas and liquid velocity from 0 to 0.04 m/s and 0.1 to 0.2 m/s respectively. From the experimental results, it was found that the local liquid velocity and the void fraction in the lead-bismuth two-phase flow take the maximum value near the wall region at low void fraction conditions. These results indicate bubbles would tend to flow along the wall surface due to the poor wettability of the test section to the lead-bismuth. To verify this hypothesis, the liquid velocity and void fraction were also measured by using a test tube with better wettability. In addition, the experimental results were compared with existing experimental results to evaluate the effect of surface wettability on flow structure of lead-bismuth.