Numerical Simulations on Mixing Dynamics of Spherical and Non-Spherical Tablets in a Pan Coater

R. Chand, R. Hadj Lajimi, S. Uddin, S. Meghwar, U. Farooq, N. Rekik

Abstract


Discrete element simulations provide valuable insight into the mixing dynamics of granular materials in industry. In this paper, numerical work is conducted in order to find the influence of pan rotational velocity and particle shape on mixing behavior. Four types of particles of different shapes were chosen: spherical, non-spherical type 1 (disk shape), non-spherical type 2 (capsule shape), and non-spherical type 3 (triangular shape). The pan mixer was filled with ~ 30 % volume of the same shape with the particles and was rotated at 15 RPM, 30 RPM, 45 RPM, and 60 RPM. The particles were colored as bottom-particles, middle-particles, and top-particles in order to visualize mixing efficiency. The homogeneity of the mixtures was determined by using contact dynamics of particles. The results show that fast-rotating pan (30-60 RPM) provides good mixing for all shapes of particles. However, non-spherical particles do not show as good mixing as spherical particles.


Keywords


granular mixing; DEM; rotaing pan; tablet coating

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References


R. D Mindlin, “Elastic spheres in contact under varying oblique forces”, Journal of Applied Mechanics, Vol. 20, pp. 327-344, 1953

R. Chand, Saeeduddin, M. A. Khaskheli, A. M. Soomro, H. Saleem, W. A. Bhutto, A. H. Nizamani, M. Y. Soomro, N. M. Shaikh, S. V. Muniandy, “Fractional analysis of light scattering data from gravity-driven granular flows”, International Journal of Computer Science and Network Security, Vol. 19, No. 7, pp. 83-89, 2019

R. Chand, A. Qadir, S. Qing-Fan, Z. Ning, S. Gang, “Anomalous increase of apparent mass in a silo due to percolation”, Chinese Physics Letters, Vol. 28, No. 9, Article ID 098301, 2011

A. Firoozfar, A. Rostami, H. Ghaderi, H. Zamani, A. Rostamkhani, “Assessing the effects of length, slope and distance between piles on the bearing capacity of a pile group under axial loading in granular soil”, Engineering, Technology & Applied Science Research, Vol. 7, No. 5, pp. 1894-1899, 2017

R. Chand, Q. Shi, A. Qadir, S. Ma, G. Sun, “Fluctuations in apparent mass at the bottom of granular columns due to different arrangements”, Physica A: Statistical Mechanics and its Applications, Vol. 391, No. 10, pp. 2936-2939, 2012

R. Chand, M. A. Khaskheli, A. Qadir, Y. Sandali, Q. Shi, “Influence of spontaneous percolation on apparent mass at the bottom of a Janssen granular column”, Physica A: Statistical Mechanics and its Applications, Vol. 393, pp. 96-100, 2014

M. A. Soomro, A. S. Brohi, M. A. Soomro, D. K. Bangwar, S. A. Bhatti, “3D numerical modeling of pile group responses to excavation-induced stress release in silty clay”, Engineering, Technology & Applied Science Research, Vol. 8, No. 1, pp. 2577-2584, 2018

R. Chand, S. V. Muniandy, C. S. Wong, J. Singh, “Discrete element method study of shear-driven granular segregation in a slowly rotating horizontal drum”, Particuology, Vol. 32, pp. 89-94, 2017

Y. Fan, K. M. Hill, “Phase transitions in shear-induced segregation of granular materials”, Physical Review Letters, Vol. 106, No. 21, Article ID 218301, 2011

M. K. Saeed, M. S. Siraj, “Mixing study of non-spherical particles using DEM”, Powder Technology, Vol. 344, pp. 617-627, 2019

R. Chand, M. A. Khaskheli, A Qadir, B. Ge, Q. Shi, “Discrete particle simulation of radial segregation in horizontally rotating drum: Effects of drum-length and non-rotating end-plates”, Physica A: Statistical Mechanics and its Applications, Vol. 391, No. 20, pp. 4590-96, 2012

A. Hassanpour, M. Pasha, M. Alizadeh, M. Ghadiri, A. Bayly, “The effect of particle shape on predicted segregation in binary powder mixtures”, Powder Technology, Vol. 319, pp. 313-322, 2017

C. Piacenza, M. Marconati, C. Hare, A. C. Santomaso, M. Ramaioli, “Mixing grains with different elongation in a rotating drums”, available at: https://arxiv.org/abs/1809.00153, 2018

J. Bridgwater, “Mixing of particles and powders: Where next?”, Particuology, Vol. 8, No. 6, pp. 563-567, 2010

J. Bridgwater, “Mixing of powders and granular materials by mechanical means-A perspective”, Particuology, Vol. 10, No. 4, pp. 397-427, 2012

E. Sahni, R. Yau, B. Chaudhuri, “Understanding granular mixing to enhance coating performance in a pan coater: Experiments and simulations”, Powder Technology, Vol. 205, No. 1-3, pp. 231-241, 2011

A. Dubey, R. Hsia, K. Saranteas, D. Brone, T, Misra, F. J. Muzzio, “Effect of speed, loading and spray pattern on coating variability in a pan coater”, Chemical Engineering Science, Vol. 66, No. 21, pp. 5107-5115, 2011

G. R. Chandratilleke, A. B. Yu, J. Bridgwater, “A DEM study of the mixing of particles induced by a flat blade”, Chemical Engineering Science, Vol. 79, pp. 54-74, 2012

L. Obregon, A. Realpe, C. Rinaldi, C. Velazquez, “Mixing of granular materials, Part I: Effect of periodic shear”, Powder Technology, Vol. 197, No. 1-2, pp. 9-16, 2010

L. Obregon, A. Realpe, C. Velazquez, “Mixing of granular materials, Part II: Effect of particle size under periodic shear”, Powder Technology, Vol. 201, No. 3, pp. 193-200, 2010

C. Henrique, G. Batrouni, D. Bideau, “Diffusion as a mixing mechanism in granular materials”, Physical Review E, Vol. 63, Article ID 011304, 2000

Y. Fan, K. M. Hill, “Theory for shear-induced segregation of dense granular mixtures”, New Journal of Physics, Vol. 13, Article ID 095009, 2011

P. A. Cundall, O. D. L. Strack, “A discrete numerical model for granular assemblies”, Geotechnique, Vol. 29, No. 1, pp. 47-65, 1979

F. Bertrand, L. A. Leclaire, G. Levecque, “DEM-based models for the mixing of granular materials”, Chemical Engineering Science, Vol. 60, No. 8-9, pp. 2517-2531, 2005

M. Rajabi, H. S. Rad, M. S. Masoudian, “A numerical model for caprock analysis for subsurface gas storage applications”, Engineering, Technology & Applied Science Research, Vol. 8, No. 1, pp. 2438-2446, 2018

Y. Tsuji, T. Tanaka, T. Ishida, “Lagrangian numerical simulation of plug flow of cohesionless particles in a horizontal pipe”, Powder Technology, Vol. 71, No. 3, pp. 239-250, 1992

www.edemsimulation.com

Y. Wang, F. Tonon, “Dynamic validation of a discrete element code in modeling rock fragmentation”, International Journal of Rock Mechanics and Mining Sciences, Vol. 48, No. 4, pp. 535-545, 2011

C. P. Alonso, J. A. Delgadillo, “Experimental validation of 2D DEM code by digital image analysis in tumbling mills”, Minerals Engineering, Vol. 25, No. 1, pp. 20-27, 2012

M. Alian, F. E. Mozaffari, S. R. Upreti, J. Wu, “Using discrete element method to analyze the mixing of the solid particles in a slant cone mixer”, Chemical Engineering Reseach and Design, Vol. 93, pp. 318-329, 2015

D. Nguyen, A. Rasmuson, I. N. Bjorn, K. Thalberg, “CFD simulation of transient particle mixing in a high shear mixer”, Powder Technology, Vol. 258, pp. 324-330, 2014

J. F. Camenen, Y. Descantes, “Geometrical properties of rigid frictionless granular packings as a function of particle size and shape”, Physical Review E, Vol. 96, Article ID 012904, 2017




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