Mixing and segregation of granular materials in chute flows

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Chaos

DOI:https://doi.org/10.1063/1.166433· OSTI ID:6470940

Khakhar, D V ^[1]; McCarthy, J J ^[2]; Ottino, J M ^[3]

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1. Department of Chemical Engineering, Indian Institute of Technology---Bombay, Powai, Mumbai 400076 (India)
2. Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)
3. Department of Chemical Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

Mixing of granular solids is invariably accompanied by segregation, however, the fundamentals of the process are not well understood. We analyze density and size segregation in a chute flow of cohesionless spherical particles by means of computations and theory based on the transport equations for a mixture of nearly elastic particles. Computations for elastic particles (Monte Carlo simulations), nearly elastic particles, and inelastic, frictional particles (particle dynamics simulations) are carried out. General expressions for the segregation fluxes due to pressure gradients and temperature gradients are derived. Simplified equations are obtained for the limiting cases of low volume fractions (ideal gas limit) and equal sized particles. Theoretical predictions of equilibrium number density profiles are in good agreement with computations for mixtures of equal sized particles with different density for all solids volume fractions, and for mixtures of different sized particles at low volume fractions ([nu][lt]0.2), when the particles are elastic or nearly elastic. In the case of inelastic, frictional particles the theory gives reasonable predictions if an appropriate effective granular temperature is assumed. The relative importance of pressure diffusion and temperature diffusion for the cases considered is discussed. [copyright] [ital 1999 American Institute of Physics.]

• OSTI ID: 6470940
• Journal Information: Chaos, Journal Name: Chaos Vol. 9:3; ISSN CHAOEH; ISSN 1054-1500
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALCULATION METHODS
GRANULAR MATERIALS
MATERIALS
MIXING
MONTE CARLO METHOD
SEGREGATION
TRANSPORT THEORY