Measuring two-phase particle flux with a multi-frequency acoustic Doppler profiler

Area of Science:

• Fluid Dynamics
• Acoustic Scattering
• Particle Characterization

Background:

• Characterizing particle suspensions is crucial for various industrial and environmental processes.
• Simultaneously measuring properties of multiple particle types presents significant challenges.
• Existing methods often lack the resolution or specificity for complex mixtures.

Purpose of the Study:

• To develop and validate a novel methodology for simultaneous, time-resolved profiling of two distinct particle types in a mixed suspension.
• To apply advanced acoustic techniques for enhanced particle characterization.
• To investigate the dynamics of settling particles in a controlled laboratory setting.

Main Methods:

• Development of a multi-frequency pulse-to-pulse coherent Doppler instrument.
• Inversion of a model based on frequency-dependent acoustic backscatter amplitude and phase.
• Laboratory experiments using a settling column with a mixture of polystyrene and glass beads.

Main Results:

• Successful simultaneous extraction of time-resolved one-dimensional profiles for mass-concentration and velocity of two particle types.
• Demonstration of the technique's ability to differentiate between strongly-scattering (polystyrene) and weakly-scattering (glass) particles.
• Quantitative data on the settling behavior of each particle type within the mixture.

Conclusions:

• The developed acoustic methodology provides a robust tool for analyzing complex particle suspensions.
• This technique offers significant advancements in non-invasive, simultaneous measurement of particle properties.
• The findings have implications for sediment transport, multiphase flow, and material processing.