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
Fluid Dynamic Behavior in a Spouted Bed with Binary Mixtures Differing in Size
TL;DR: In this paper, the response surface methodology has been used to quantify the effect of the mixture composition and static bed height on the minimum spouting condition, as well as on the segregation phenomena, for a spouted bed operating with binary mixtures, differing in size.
Journal ArticleDOI
DEM investigation of shear flows of binary mixtures of non-spherical particles
TL;DR: In this article, discrete element method (DEM) simulations of shear flows of binary mixtures of large non-spherical glued-sphere particles and small spheres are conducted in order to investigate the effect of particle shape and solid volume fraction ratio on the behavior of binary granular flows.
Journal ArticleDOI
Coupling of material point method and discrete element method for granular flows impacting simulations
TL;DR: In this article, a material point method (MPMM) and a deformable discrete element method (DEM) are used to model granular debris flows in a sandpile collapse scenario.
Journal ArticleDOI
Mesh size effect on CFD simulation of gas-fluidized Geldart A particles
Priya C. Sande,Saumi Ray +1 more
TL;DR: In this article, the effect of mesh size on CFD simulations of a lab-scale sized fluidized bed of Geldart A particles using two-fluid model (TFM), specifically for homogeneous expansion and transition to bubbling was investigated.
DissertationDOI
Computational fluid dynamics simulation of fluidized bed polymerization reactors
TL;DR: In this article, a simulation of a polyethylene pilot-scale fluidized bed polymerization (FB) reactor is presented, and the results for a constant aggregation and breakage kernel and a kernel developed from kinetic theory are shown.
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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