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
Derivation and validation of a binary multi-fluid Eulerian model for fluidized beds
TL;DR: In this article, a multi-fluid Eulerian model derived from binary kinetic theory of granular flows, free path theory and an empirical friction theory is presented, which gives reasonable predictions of the particle volume fraction, particle velocities and velocity fluctuations.
Journal ArticleDOI
Macroscopic behavior of vibrating beds of smooth inelastic spheres
Yidan Lan,Anthony D. Rosato +1 more
TL;DR: In this paper, a three-dimensional simulation of a periodic cell with an open top and plane floor is carried out to investigate macroscopic behavior of granular materials subjected to vibrations.
Journal ArticleDOI
Towards a hybrid Eulerian–Lagrangian CFD modeling of coal gasification in a circulating fluidized bed reactor
TL;DR: In this paper, the Dense Discrete Phase Model (DDPM) model of ANSYS FLUENT is used to simulate the flow of the particulate phase in the coal gasifier.
Journal ArticleDOI
CFD simulation of the high shear mixing process using kinetic theory of granular flow and frictional stress models
TL;DR: In this paper, the Eulerian-Eulerian approach was used to model multiphase flows in high shear granulation, and the results showed that the bed height could be well predicted by implementing the partial slip model, whereas the free slip model could not capture the experimentally found bed height satisfactorily.
Journal ArticleDOI
Computational fluid dynamics modelling of biomass fast pyrolysis in fluidised bed reactors, focusing different kinetic schemes
Panneerselvam Ranganathan,Sai Gu +1 more
TL;DR: A parametric study was carried out to study the effect of biomass particle type and size and temperature on the yield of the products and found that CFD prediction with the advanced kinetic scheme is better when compared to other schemes.
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