A CFD-based integral pump-down model for computing solids transfer from a mixing vessel

A method to decrease the modeling time for a computational fluid dynamics (CFD) simulation of the pump-out process of a multi-constituent, radioactive slurry in a mixing vessel is developed. Although a true CFD simulation of transferring such slurry from a vessel is possible, the process requires the simulation of about a five - to ten-hour process (real-time). To reduce this time, a method is developed based on extracting information from CFD models at discrete stages during the vessel pump-down process. These discrete CFD models are used to feed a control-volume analysis. The result is the reduction in the computational time by eighty to ninety percent, while retaining the ability to compute the waste contents of each constituent through the pump-down process to high accuracy (< 4% error in mass transferred from a vessel). Current efforts are evaluating the coupling of CFD models with seven inhomogeneous phases. The overall result is a more efficient and effective CFD model that represents a true CFD simulation of a vessel pump down to high accuracy.