Erosion Modeling Analysis for DWPF MFT/SME Tanks

摘要

In support of an erosion evaluation for the cooling coil guide and its supporting structure in the MFT vessel, computational models were developed to identify potential sites of high erosion. Two mechanisms were considered to evaluate high erosion locations representative of the actual flow process in the coil guide of the MFT vessel, abrasive erosion which occurs by high wall shear of viscous liquid, and chip-off erosion which is mainly governed by particle impingement. The results show that primary locations of the highest erosion due to the abrasive wall erosion are at the leading edge of the guide, the tank floor below the insert plate of the coil guide support, and the upstream lead-in plate. The modeling results are consistent with the observed damage to the coil guide of the SME vessel. The modeling results show a good comparison between the observed erosion sites and the calculated locations of high shear regions, as well as the degree of erosion and the calculated shear stress. It is noted that the loss of the leading edge of the coil guide due to the erosion damage during the SME mixing operation does not affect the erosion patterns on the tank floor. Calculations for the lower impeller speed in the MFT showed similar erosion patterns but significantly reduced wall shear stresses. Comparisons with SME measurements indicated that no significant erosion of the tank floor in the MFT is to be expected.