Speaker
Description
Existing radionuclide aerosol collection systems within the CTBT’s International Monitoring System operate near the noise floor of the gamma spectrometer measurement. Increasing the flow rate of radionuclide aerosol systems while meeting the CTBT’s specified collection efficiencies will increase particle collection and, potentially, decrease sample interval. Creare developed a detailed model of an agglomeration system designed for the particularly hard-to-collect small particles and low particle densities of interest. Our design uses an array of acoustic horns and drivers in the confined flow area to drive the agglomeration of small particles with larger particles or seed aerosols, making them easier to collect. Our agglomeration model includes effects from orthokinetic, acoustic wake, particle collision efficiency, population balance, Brownian motion, and van der Waals forces to predict the statistical likelihood of any particle sticking to any other particle in the turbulent flow stream with high sound pressure. Our statistical and finite element analysis modeling results show the need for fine seed particles to enhance agglomeration efficiency by increasing relative particle density. We also detailed the effect of changing the residence time of the particles in the flow field, the effect of frequency, and sound pressure level.
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