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Ultrasonic wave propagation in concentrated slurries--the modelling problem.
Richard E Challis1, Valerie J Pinfield2
1Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
Ultrasonics
|May 3, 2014
Summary
Estimating particle size distribution in slurries using ultrasonic wave attenuation is challenging at high concentrations. This study found that simple effective medium models fail, but core-shell models show promise for improved particle sizing procedures.
Area of Science:
- Materials Science
- Acoustics
- Chemical Engineering
Background:
- Ultrasonic wave attenuation can estimate particle size distribution in slurries.
- Current computational models struggle with high particle concentrations due to unaddressed hydrodynamic effects.
Purpose of the Study:
- To find effective viscosity and density for particle scattering models at high solids loading.
- To enable scattering model predictions to match experimental data in concentrated slurries.
Main Methods:
- Investigated effective medium modifications to the ECAH/LB model.
- Utilized core-shell scattering models for particle size estimation.
- Analyzed ultrasonic wave attenuation across a 10s of MHz frequency band.
Main Results:
- A simple effective medium modification was found to be unphysical.
- Core-shell scattering models successfully estimated particle sizes for smaller particles than previously studied.
- The limitations of current models at high particle concentrations were confirmed.
Conclusions:
- Simple effective medium approaches are insufficient for modeling high concentration slurries.
- Core-shell models offer a viable path for accurate particle sizing, with potential for computational optimization.
- Further research is needed to incorporate hydrodynamic effects for comprehensive slurry characterization.
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