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TitleVelocity and attenuation of sound: Application to flow rate measurement in pneumatic conveying
Publication TypeJournal Article
Year of Publication1996
AuthorsTallon, S., and Davies C.E.
JournalPowder Handling and Processing
Pagination329 - 336
Date Published1996
ISSN09347348 (ISSN)
KeywordsAcoustic wave diffraction, Acoustic wave velocity, Attenuation, Conveying, Flow measurement, FLOW OF FLUIDS, Flow of solids, Pipelines, Pneumatic conveyors, Pressure transducers, Pressure waves, Rootes air blower, Solids concentration
AbstractThe velocity and attenuation of an acoustic pressure wave travelling along a pneumatic conveying pipeline is a strong function of the flow rates of both the gas and solids phases. By measuring the passage of these waves, using pressure transducers at the wall of the pipe, an on-line estimate of the solids flow rate can be made. Acoustic waves exist naturally in many systems, generated for example by the air mover, or can be easily introduced to the pipeline. The waves can also be accurately and cheaply measured by attaching a pressure tap and transducer to the pipe wall. In this work, measurements are made of the velocity and attenuation of the pressure waves generated by the Rootes blower supplying the air, and by an additional, introduced, sound source. The velocity of the gas phase was estimated from its effect on the sound velocity through the pipe, and correlations are developed between the attenuation of the waves and the solids concentration. The experiments were carried out in a 73.6 mm internal, diameter conveying line in both horizontal and vertical orientations for a range of conveying velocities, and for solids to air mass flow ratios up to 5:1.

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