Ultrasonic wave propagation in concentrated slurries--the modelling problem.
The suspended particle size distribution in slurries can, in principle, be estimated from measured ultrasonic wave attenuation across a frequency band in the 10s of MHz range. The procedure requires a computational model of wave propagation which incorporates scattering phenomena. These models fail at high particle concentrations due to hydrodynamic effects which they do not incorporate. This work seeks an effective viscosity and density for the medium surrounding the particles, which would enable the scattering model predictions to match experimental data for high solids loading. It is found that the required viscosity model has unphysical characteristics leading to the conclusion that a simple effective medium modification to the ECAH/LB is not possible. The paper confirms the successful results which can be obtained using core-shell scattering models, for smaller particles than had previously been studied, and outlines modifications to these which would permit rapid computation of sufficient stability to support fast particle sizing procedures.
Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK. Electronic address: Richard.challis@nottingham.ac.uk.
Richard E
RE
Challis
Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, UK.
Valerie J
VJ
Pinfield
D003198:Computer Simulation; D057446:Hydrodynamics; D008956:Models, Chemical; D010316:Particle Size; D013499:Surface Properties; D013535:Suspensions / Q000737:chemistry*; D014465:Ultrasonics; D014783:Viscosity
D013535:Suspensions
Core–shell; Scattering; Ultrasound; Viscosity