Journal ArticleDOI
Kinetic theories for granular flow: inelastic particles in Couette flow and slightly inelastic particles in a general flowfield
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In this paper, the authors studied the flow of an idealized granular material consisting of uniform smooth, but nelastic, spherical particles using statistical methods analogous to those used in the kinetic theory of gases.Abstract:
The flow of an idealized granular material consisting of uniform smooth, but nelastic, spherical particles is studied using statistical methods analogous to those used in the kinetic theory of gases. Two theories are developed: one for the Couette flow of particles having arbitrary coefficients of restitution (inelastic particles) and a second for the general flow of particles with coefficients of restitution near 1 (slightly inelastic particles). The study of inelastic particles in Couette flow follows the method of Savage & Jeffrey (1981) and uses an ad hoc distribution function to describe the collisions between particles. The results of this first analysis are compared with other theories of granular flow, with the Chapman-Enskog dense-gas theory, and with experiments. The theory agrees moderately well with experimental data and it is found that the asymptotic analysis of Jenkins & Savage (1983), which was developed for slightly inelastic particles, surprisingly gives results similar to the first theory even for highly inelastic particles. Therefore the ‘nearly elastic’ approximation is pursued as a second theory using an approach that is closer to the established methods of Chapman-Enskog gas theory. The new approach which determines the collisional distribution functions by a rational approximation scheme, is applicable to general flowfields, not just simple shear. It incorporates kinetic as well as collisional contributions to the constitutive equations for stress and energy flux and is thus appropriate for dilute as well as dense concentrations of solids. When the collisional contributions are dominant, it predicts stresses similar to the first analysis for the simple shear case.read more
Citations
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Journal ArticleDOI
Interaction of a shock wave with a loose dusty bulk layer
TL;DR: In this article, the interaction of a planar shock wave with a loose dusty bulk layer has been investigated both experimentally and numerically both by means of shadowgraphs and pulsed X-ray radiography with trace particles added.
Journal ArticleDOI
Granular Collision Lubrication: Experimental Investigation and Comparison to Theory
TL;DR: In this paper, an experimental investigation of the friction and lift characteristics of granular lubrication is presented, where experiments are carried out to demonstrate the vertical displacement (lift) observed in an annular shear cell apparatus.
Journal ArticleDOI
CFD investigation of hydrodynamics, heat transfer and cracking reactions in a large-scale fluidized catalytic cracking riser
Qi Yang,Qi Yang,Abdallah S. Berrouk,Yupeng Du,Hui Zhao,Chaohe Yang,Mohammad Abdur Rakib,Abdulhamid Mohamed,Anood Taher +8 more
TL;DR: In this paper, a three-dimensional reactive gas-particle CFD model was built to study the hydrodynamics, heat transfer and cracking reaction behaviors within an industrial Fluid Catalytic Cracking (FCC) riser reactor designed to maximize propylene production.
Journal ArticleDOI
Characterization of fluidized bed layer inversion in a 191-mm-diameter column using both experimental and CPFD approaches
TL;DR: In this article, a bed containing equal volumes of 1.85mm glass beads and 0.550mm ceramic spheres was fluidized by water in a 191mm i.d. cylindrical column.
Journal ArticleDOI
Investigation of Flow Behaviors and Bubble Characteristics of a Pulse Fluidized Bed via CFD Modeling
TL;DR: In this article, a 2D pulsed fluidized bed is simulated using a developed Eulerian-Eulerian two-fluid modeling approach and the bubble formation, coalescence, split-up of air bubbles, and their trailing wakes inside the bed are described and discussed in detail.
References
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Journal ArticleDOI
Equation of State for Nonattracting Rigid Spheres
TL;DR: In this paper, a new equation of state for rigid spheres has been developed from an analysis of the reduced virial series, which possesses superior ability to describe rigid-sphere behavior compared with existing equations.
Journal ArticleDOI
Experiments on a Gravity-Free Dispersion of Large Solid Spheres in a Newtonian Fluid under Shear
TL;DR: In this article, a large number of spherical grains of diameter D = 0.13 cm were sheared in Newtonian fluids of varying viscosity (water and a glycerine-water-alcohol mixture) in the annular space between two concentric drums.
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