The large octahedral crystals of spinel can precipitate from glass during the high-level waste vitrification process and potentially block the glass discharge riser of electrically heated ceramic melters. To help predict the settling behavior of spinel in the riser, the settling of single particles and agglomerates was studied in stagnant and transparent viscosity oils at room temperature with developed optical particle-dynamics-analyzer. Determined dimensions and terminal settling velocities of particles were used for calculation of their Stokes shape factors. Calculated shape factor for the glass beads was almost identical with the theoretical shape factor of 2/9 for a perfect sphere. The shape factor for single spinel crystal was about 7.6 % higher compare to the theoretically predicted value for octahedron. Stokes shape factor of irregularly shaped multi-particle agglomerates was lower than that of the glass beads and individual spinel crystals because of the higher surface drag caused by the larger surface area to volume ratio.
Revised: October 27, 2011 |
Published: September 1, 2011
Citation
Matyas J., M.J. Schaible, and J.D. Vienna. 2011.DETERMINATION OF STOKES SHAPE FACTOR FOR SINGLE PARTICLES AND AGGLOMERATES. In Advances in Materials Science for Environmental and Nuclear Technology II: Papers from Symosia held at the Materials Science & Technology Conference and Exhibition (MS&T 2010), October 17-21, 2010, Houston, Texas. Ceramic Transactions, edited by SK Sundaram, T Ohji, K Fox and E Hoffman, 227, 195-203. Hoboken, New Jersey:Wiley.PNNL-SA-75367.