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Particle Pressure And Marginal Stability Limits For A Homogeneous Monodisperse Gas-Fluidized Bed: Kinetic Theory And Numerical Simulations, Ashok S. Sangani, Donald L. Koch
Particle Pressure And Marginal Stability Limits For A Homogeneous Monodisperse Gas-Fluidized Bed: Kinetic Theory And Numerical Simulations, Ashok S. Sangani, Donald L. Koch
Ashok S. Sangani
A linear stability analysis is performed for the homogeneous state of a monodisperse gas-fluidized bed of spherical particles undergoing hydrodynamic interactions and solid-body collisions at small particle Reynolds number and finite Stokes number. A prerequisite for the stability analysis is the determination of the particle velocity variance which controls the particle-phase pressure. In the absence of an imposed shear, this velocity variance arises solely due to the hydrodynamic interactions among the particles. Since the uniform state of these suspensions is unstable over a wide range of values of particle volume fraction &phgr; and Stokes number St, full dynamic simulations cannot …
Determination Of Particle Size Distributions From Acoustic Wave Propagation Measurements, Ashok S. Sangani, Peter D. M. Spelt, Michael A. Norato, Lawrence L. Tavlarides
Determination Of Particle Size Distributions From Acoustic Wave Propagation Measurements, Ashok S. Sangani, Peter D. M. Spelt, Michael A. Norato, Lawrence L. Tavlarides
Ashok S. Sangani
The wave equations for the interior and exterior of the particles are ensemble averaged and combined with an analysis by Allegra and Hawley @J. Acoust. Soc. Am. 51, 1545 ~1972!# for the interaction of a single particle with the incident wave to determine the phase speed and attenuation of sound waves propagating through dilute slurries. The theory is shown to compare very well with the measured attenuation. The inverse problem, i.e., the problem of determining the particle size distribution given the attenuation as a function of frequency, is examined using regularization techniques that have been successful for bubbly liquids. It …