(331a) Study of Jet Splashing at Liquid/Gas Interface in an Oxide Reduction Electrochemical Cell

An oxide reduction is a head-end operation extending the pyroprocessing technology, which is currently in operation at Idaho National Laboratory, to oxide-based fuels. During this process, uranium oxide is converted to uranium metal (cathode) and to oxygen gas (anode) within a molten salt electrolyte (LiCl) at 650 ºC by electrolytic technique. Despite extensive research and development of the oxide reduction process, there is still a concern regarding the generation of oxygen bubbles around the anode that travel up and burst at a free surface. This splashing event plays an important role in mass transfer between phases and has not been thoroughly investigated, thereby providing the motivation to study the effect of physical properties and device geometry on bubble size distribution for gas-liquid interaction in this electrolytic reduction process.

To theoretically predict and experimentally assess this problem, a fundamental mock-up study for this process has been designed to focus on the effect of continuous phase viscosity on these jet drops population during bursting gas bubble processes. To vary this parameter, bubbles are generated using an electrochemical technique in glycerol, water, and glycerol/water solutions. The reasons for choosing these liquid mediums relate to the physical properties of actual LiCl used in pyrochemical operations. A high-speed imaging study of gas bubbles bursting at a gas/liquid interface will be performed. Results will be given and discussed along with a qualitative explanation.