Journal ArticleDOI
Kinetic theories for granular flow: inelastic particles in Couette flow and slightly inelastic particles in a general flowfield
Reads0
Chats0
TLDR
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
More filters
Journal ArticleDOI
Numerical Simulation of Particle Segregation in Bubbling Gas-Fluidized Beds
TL;DR: In this paper, a multi-fluid Eulerian model incorporating the kinetic theory of granular flow is used for the simulation of bubbling fluidized beds containing a binary mixture of Geldart B particles at low gas velocities.
Journal ArticleDOI
Mathematical modelling of shallow flows: Closure models drawn from grain-scale mechanics of sediment transport and flow hydrodynamicsThis paper is one of a selection of papers in this Special Issue in honour of Professor M. Selim Yalin (1925–2007).
Rui Ferreira,Rui Ferreira,Rui Ferreira,Mário J. FrancaM.J. Franca,Mário J. FrancaM.J. Franca,Mário J. FrancaM.J. Franca,João Leal,João Leal,João Leal,A. H. Cardoso,A. H. Cardoso,A. H. Cardoso +11 more
TL;DR: In this article, the authors describe conceptual models of sediment transport, deduced from grain-scale mechanics for sediment transport and turbulent flow hydrodynamics, and present solutions to specific river morphology problems.
Journal ArticleDOI
Computational fluid dynamics simulation of hydrodynamics and chemical reaction in a CFB downer
TL;DR: In this paper, a computational fluid dynamics (CFD) model for simulating the chemical reaction process in a gas-particle circulating fluidized bed (CFB downer) is introduced by combining the two-fluid model (TFM) for the gasparticle turbulent flows and the c 2 ¯ − e c model for the turbulent mass transfer.
Journal ArticleDOI
Simulation of particle attrition by supersonic gas jets in fluidized beds
TL;DR: In this article, a mathematical model for particle attrition by high velocity gas jets is developed, which utilizes an Eulerian-Eulerian approach for the gaseous and particulate phases coupled with the kinetic theory of granular flow and a novel attrition model connecting the solid phase properties and the granular temperature with the breakage rate.
Journal ArticleDOI
The effect of microstructure development on the collisional stress tensor in a granular flow
TL;DR: In this article, the effect of microstructure development for two-dimensional granular flows was addressed by incorporating a heuristic model of the microstructures into a simple theoretical analysis.
References
More filters
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.
Related Papers (5)
Frictional–collisional constitutive relations for granular materials, with application to plane shearing
P. C. Johnson,R. Jackson +1 more
A bubbling fluidization model using kinetic theory of granular flow
Jianmin Ding,Dimitri Gidaspow +1 more