See Research subjects

Multiscale modelling of segregation in rotating drums

PROJECT DESCRIPTION

Based on the experimental and theoretical understanding of granular segregation in general, we collectively developed a new model that intends to, qualitatively and quantitatively, predict segregation for bidisperse mixtures in both rotating drums and chute flows. The model constitutes the effects of, both, particle size and density and has the ability to predict several states observed in rotating drum experiments and DPM simulations.

MercuryDPM is currently being utilised to simulate very long drums and to investigate the 3D banding instability. In the future it would be used to investigate segregating in very long chute; following on from the current work on bi-disperse bulbous head formation. Also we have investigated the effect of different shaped drums .

The experimental investigation of rotating drums has thus far proved highly fruitful, producing to date two published papers with several more in preparation. The work demonstrates various manners in which the geometry of a system may be exploited to induce, direct, strengthen or suppress segregation — all highly valuable abilities for a variety of industries and scientific fields — as well as providing a deep insight into the many different physical mechanisms underlying the segregation of rotated granular systems [35,39,46].

Additionally, the RIMS setup at EPFL has been used to get a fully 3D picture of the segregation in these drums. The data-analysis is still underway and we have developed a new more accurate way of reconstructing the particle position from RIMS data. This new image analysis code is now being generalised, such that the same code can be used to analyse all the experimental data from RIMS, optical, PEPT etc. Experimental work has also been conducted exploring the fundamental nature of segregative behaviours of these systems; specifically, a series of binary and ternary systems have been studied in order to establish whether the known segregative behaviours of the former can be used to predict those of the latter. Work is also underway providing a cross-comparison of data acquired using RIMS, PEPT and relatively simple optical imaging, in order to provide both a mutual validation of the three techniques, and a deeper insight into the systems studied than is possible using any single technique in isolation. Additionally, we are now constructing a second RIMS facility at the University of Twente.

Left: Experiments of bidisperse granular material in a rotating drum. (a)flow in pentagram (b)flow in pentagon Right: PEPT image for circular drum.

PEOPLE INVOLVED

Dr. S. Gonzalez Briones (Sebastian)

Prof.Dr. A.R. Thornton (Anthony)

Prof.Dr. S.A. Luding (Stefan)

Dr. W.K. den Otter (Wouter)

Dr. D. Tunuguntla (Deepak)

Dr. K. Windows-Yule (Kit)

Dr. I.F.C. Denissen (Irana)

Dr. M.P. van Schrojenstein Lantman (Marnix)