Enhanced Mass Transfer of Deuterium Extracted from Falling Liquid Pb-17Li Droplets

Release of deuterium from falling droplets of Pb-17Li in vacuum is experimentally studied. By comparing different diameter nozzle data each other, the effect of ambiguous solution is eliminated, and reliable result is attained. The amount of deuterium that is dissolved into Pb-17Li, followed by the release from the liquid droplets in vacuum, is measured with four different diameter nozzles ranging from 0.4 mm-1.0 mm under an initial velocity of 3.0 m/s and four temperatures between 375 °C and 450 °C. The resultant mass transport, represented by quasi-dispersion-coefficient is 3.4 × 10^-7 [m²/s], which is approximately two orders of magnitude faster than previous studies under static condition. It also revealed different temperature dependency. Cyclic deformation of the sphere shape is observed with a high speed movie camera. These results show the falling droplets of liquid Pb-17Li in vacuum follow the mass transfer mechanism under convection prior domain by self- excited oscillation. This result suggests that the tritium recovery method from a breeding liquid Pb-17Li blanket is viable when using multiple nozzles in vacuum for the extraction.