Abstract
Using DEM particle simulations we consider segregation of a binary granular particle mixture in a slowly rotating cylindrical tumbler where the particles differ only in their shape—spherical versus more cubical particles. We find that the more cubical particles segregate to the inner core of the particle bed while the spherical particles segregate to the curved walls of the tumbler. The main mechanism for this segregation is different energy dissipation rates for the different particle shape types when avalanching down along the free surface. The cubical particles, due to their sharper corners, dissipate energy much faster than the spherical particles. This results in spherical particles reaching the bottom end of the sloped, free surface which are then transported around the cylinder adjacent to the cylinder wall, as rigid body motion. In contrast to size or density segregation, the segregation due to shape is much weaker and takes longer to reach its equilibrium or steady state. In addition, the segregation occurs along the top surface rather than through the top surface (as occurs for size and density segregation). In general, in situations where two particles differ in their ease of flow (viz flowability) the more rapidly flowing particle will segregate to the base of the free surface (which in the case of the tumbler results in spherical particles near the periphery) and the more slowly flowing particle will segregate underneath.
Similar content being viewed by others
References
Ottino, J.M., Khakhar, D.V.: Mixing and segregation of granular materials. Ann. Rev. Fluid Mech. 32, 55–91 (2000)
Bridgwater, J., Foo, W.S., Stephens, D.J.: Particle mixing and segregation in failure zones—theory and experiment. Powder Technol. 41, 147–158 (1985)
Savage, S.B., Lun, C.K.K.: Particle size segregation in inclined chute flow of dry cohesionless granular solids. J. Fluid Mech. 180, 311–335 (1988)
Gray, J.M.N.T., Ancey, C.: Multi-component particle-size segregation in shallow granular avalanches. J. Fluid Mech. 678, 535–588 (2011)
Gray, J.M.N.T., Thornton, A.R.: A theory of particle size segregation in shallow granular free surface flows. Proc. R. Soc. Lond. A 461, 1447–1473 (2005)
Khakhar, D.V., McCarthy, J.J., Ottino, J.J.: Radial segregation of granular mixtures in rotating tumblers. Phys. Fluids 9, 3600–3614 (1997)
Boutreux, T., de Gennes, P.G.: Surface flows of granular mixtures: I. General principles and minimal model. J. de Phys. I 6, 1295–1304 (1996)
Pereira, G.G., Sinnott, M.D., Cleary, P.W., Liffman, K., Metcalfe, G., Šutalo, I.D.: Insights from simulations into mechanisms for density segregation of granular mixtures in rotating cylinders. Granul. Matter 13, 53–74 (2011)
Pereira, G.G., Pucilowski, S., Liffman, K., Cleary, P.W.: Streak patterns in binary granular media in a rotary classifier. Appl. Math. Model. 35, 1638–1646 (2011)
Fan, Y., Schlick, C.P., Umbanhowar, P.B., Ottino, J.M., Lueptow, R.M.: Modelling size segregation of granular materials: the roles of segregation, advection and diffusion. J. Fluid Mech. 741, 252–279 (2014)
Tunuguntla, D.R., Bokhove, O., Thornton, A.R.: A mixture theory for size and density segregation in shallow granular flows. J. Fluid Mech. 749, 99–112 (2014)
Marks, B., Rognon, P., Einav, I.: Grain-size dynamics of polydisperse granular segregation down inclined planes. J. Fluid Mech. 690, 499–511 (2012)
Pereira, G.G., Cleary, P.W.: Radial segregation of multi-component granular media in a rotating tumbler. Granul. Matter 15, 705–724 (2013)
Pereira, G.G., Tran, N., Cleary, P.W.: Segregation of combined size and density varying binary granular mixtures in a slowly rotating tumbler. Granul. Matter 16, 711–732 (2014)
Arntz, M.M.H.D., Beeftink, H.H., den Otter, W.K., Briels, W.J., Boom, R.M.: Segregation of granular particles by mass, radius and density in a horizontal rotating drum. AICHE J. 60, 50–59 (2014)
Fan, Y., Hill, K.M.: Shear induced segregation of particles by material density. Phys. Rev. E 92(2), 1–9 (2015)
Santos, D.A., Barrozo, M.A.S., Duarte, C.R., Weigler, F., Mellmann, J.: Investigation of particle dynamics in a rotary drum by means of experiments and numerical simulations using DEM. Adv. Powder Technol. 27, 692–703 (2016)
Schlick, C.P., Fan, Y., Umbanhowar, P.B., Ottino, J.M., Lueptow, R.M.: Granular segregation in circular tumblers: theoretical model and scaling laws. J. Fluid Mech. 765, 632–652 (2015)
Lu, G., Third, J.R., Muller, C.R.: Discrete element models for non-spherical particle systems: From theoretical developments to applications. Chem. Eng. Sci. 127, 425–465 (2015)
Pollard, B.L., Henein, H.: Kinetics of radial segregation of different sized irregular particles in rotary cylinders. Can. Metal. Quat. 28, 29–40 (1989)
Dube, O., Alizadeh, E., Chaouki, J., Bertrand, F.: Dynamics of non-spherical particles in a rotating drum. Chem. Eng. Sci. 101, 486–502 (2013)
Caulkin, R., Jia, X., Fairweather, M., Williams, R.A.: Geometric aspects of particle segregation. Phys. Rev. E 81(5), 1–9 (2010)
Makse, H.A., Havlin, S., King, P.R., Stanley, H.E.: Spontaneous stratification in granular mixtures. Nature 386, 379–382 (1997)
Makse, H.A., Cizeau, H.A., Stanley, H.E.: Possible stratification mechanisms in granular mixtures. Phys. Rev. Lett. 78, 3298–3301 (1997)
Makse, H.A.: Stratification instability in granular flows. Phys. Rev. E 56, 7008–7016 (1997)
Wachs, A., Girolami, L., Vinay, G., Ferrer, G.: Grains3D, a flexible DEM approach for particles of arbitrary convex shape—Part I: numerical model and validations. Powder Technol. 224, 374–389 (2012)
Hohner, D., Wirtz, S., Scherer, V.: A study on the influence of particle shape and shape approximation on particle mechanics in a rotating drum using the discrete element method. Powder Technol. 253, 256–265 (2014)
Cleary, P.W.: Industrial particle flow modelling using the discrete element method. Eng. Comput. 26, 698–743 (2009)
Hayter, D., Pereira, G., Liffman, K., Aldham, B., Johns, S., Šutalo, I., Brooks, G., Cleary, P., Metcalfe, G.: Density segregation of granular material in a rotating cylindrical tumbler, Proceeding of SPIE, 7270, 727010(1–10), (2008)
Pereira, G.G., Cleary, P.W.: De-mixing of binary particle mixtures during unloading from a V-blender. Chem. Eng. Sci. 94, 93–107 (2013)
Cleary, P.W.: Large scale industrial DEM modelling. Eng. Comput. 21, 169–204 (2004)
Cleary, P.W.: The effect of particle shape on simple shear flows. Powder Tech. 179, 144–163 (2008)
Cleary, P.W.: Granular flows fundamentals and applications, Chap. 8, in Granular and Complex Materials, World Scientific Lecture Notes in Complex Systems (eds: T. Aste, T. Di Matteo and A. Tordesillas), 8, 141–168, (2007)
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
Pereira, G.G., Cleary, P.W. Segregation due to particle shape of a granular mixture in a slowly rotating tumbler. Granular Matter 19, 23 (2017). https://doi.org/10.1007/s10035-017-0708-7
Received:
Published:
DOI: https://doi.org/10.1007/s10035-017-0708-7