Model and Analysis for Kinetics of Agglomerate Erosion in Simple Shear Flows

摘要

A model for the erosion kinetics of powder agglomerates in simple shear flows was developed.The model assumes the erosion rate to be proportional with the difference between hydrodynamic and cohesive forces and with the rotation velocity of the dispersing agglomerate.For dispersion under identical hydrodynamic conditions,the model predicts faster erosion for larger agglomerates.Moreover,at comparable stresses,erosion is enhanced at higher shear rates.Dispersion experiments using silica agglomerates of various densities and liquid low molecular weight polymers(poly(dimethyl siloxanc))of different viscosi-ties were conducted in an oscillatory shear flow device.The results validate the model which well predicts the general shape of the erosion kinetic curve as well as the effect of viscosity,shear rate and agglomerate size.The model can also predict erosion for fractal agglomerates and can potentially include the effect of infiltration.