Multiple-Relaxation-Time Lattice Boltzmann Model for Multiphase Flows in Three Dimensions

The production of plutonium at DOE’s Hanford Site during the cold war has resulted in millions of gallons of radioactive waste
stored in various sites across the U.S. The waste exists in the liquid and solid form and kept in underground tanks some of
which have been detected to leak due to the mechanical degradation and aging of the tank walls. The waste is being
transferred to double shell tanks which are more leak-resistant and various waste retrieval and processing methods are
employed during this process. Mixing of the liquid-solid waste in the tanks using pulsed-jet mixers coupled with air spargers is
one of such operations that requires understanding the physical nature of the interaction of multiple fluid phases in the tank
environment in order to optimize the mixing effectiveness considering various waste properties. Such an analysis can be
made possible by developing a numerical method that can simulate the process of injection of gas and liquid jets inside tanks
filled with liquid.