OpenAIRE is about to release its new face with lots of new content and services.
During September, you may notice downtime in services, while some functionalities (e.g. user registration, login, validation, claiming) will be temporarily disabled.
We apologize for the inconvenience, please stay tuned!
For further information please contact helpdesk[at]

fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Pasha, M.; Hare, C.; Hassanpour, A.; Ghadiri, M. (2015)
Publisher: Elsevier BV
Journal: Chemical Engineering Science
Languages: English
Types: Article
Subjects: Applied Mathematics, Chemistry(all), Chemical Engineering(all), Industrial and Manufacturing Engineering
In the shear deformation of powder beds beyond the quasi-static regime the shear stress is dependent on the strain rate. Extensive work has been reported on the rapid chute flow of large granules but the intermediate regime has not been widely addressed particularly in the case of cohesive powders. However in industrial powder processes the powder flow is often in the intermediate regime. In the present work an attempt is made to investigate the sensitivity of the stresses in an assembly of cohesive spherical particles to the strain rate in ball indentation using the Distinct Element Method. This technique has recently been proposed as a quick and easy way to assess the flowability of cohesive powders. It is shown that the hardness, deviatoric and hydrostatic stresses within a bed, subjected to ball indentation on its free surface, are dependent on the indentation strain rate. These stresses are almost constant up to a dimensionless strain rate of unity, consistent with trends from traditional methods of shear cell testing, though fluctuations begin to increase from a dimensionless strain rate of 0.5. For dimensionless strain rates greater than unity, these stresses increase, with the increase in hardness being the most substantial. These trends correlate well with those established in the literature for the Couette device. However quantitative value of the strain rate boundaries of the regimes differ, due to differences in the geometry of shear deformation band. Nevertheless, this shows the capability of the indentation technique in capturing the dynamics of cohesive powder flow.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • Bagi, K., 1996. Stress and strain in granular assemblies. Mech. Mater. 22, 165-177.
    • Bagnold, R.A., 1954. Experiments on a gravity-free dispersion of large solid spheres in a newtonian fluid under shear. P. Roy. Soc. Lond. Ser. A. Mat. Phys. Sci. 225, 49-63.
    • Bharadwaj, R., Ketterhagen, W.R., Hancock, B.C., 2010. Discrete element simulation study of a freeman powder rheometer. Chem. Eng. Sci. 65, 5747-5756.
    • Campbell, C.S., Brennen, C.E., 1985. Computer simulation of granular shear flows. J. Fluid Mech. 151, 167-188.
    • Castellanos, A., Valverde, J.M., Quintanilla, M.A.S., 2004. The sevilla powder tester: a tool for characterizing the physical properties of fine cohesive powders at very small consolidations. Kona 22, 66-81.
    • Cundall, P.A., Strack, O.D.L., 1979. A discrete numerical model for granular assemblies. Geotechnique 29, 47-65.
    • Formisani, B., Bernado, P., Girimonte, R., Minnicelli, A. 2002, The bed support experiment in the analysis of the fluidization properties of fine solids, 4th World Congress on Particle Technology, Sydney, Australia, 21-26.
    • Freeman, R., 2007. Measuring the flow properties of consolidated, conditioned and aerated powders - a comparative study using a powder rheometer and a rotational shear cell. Powder Technol. 174, 25-33.
    • Hare, C., Ghadiri, M., Dennehy, R., 2011. Prediction of attrition in agitated particle beds. Chem. Eng. Sci. 66, 4757-4770.
    • Hassanpour, A., Ghadiri, M., 2007. Characterisation of flowability of loosely compacted cohesive powders by indentation. Part. Part. Syst. Char. 24, 117-123.
    • Johnson, K.L., Kendall, K., Roberts, A.D., 1971. Surface energy and the contact of elastic solids. P. Roy. Soc. Lond. A. Mat. Phys. Sci. 324, 301-313.
    • Luding, S., 2008. Constitutive relations for the shear band evolution in granular matter under large strain. Particuology 6, 501-505.
    • Moreno-Atanasio, R., Antony, S.J., Ghadiri, M., 2005. Analysis of flowability of cohesive powders using Distinct Element Method. Powder Technol. 158, 51-57.
    • Parrella, L., Barletta, D., Boerefijin, R., Poletto, M., 2008. Comparison between a uniaxial compaction tester and a shear tester for the characterisation of powder flowability. KONA Powder Part. J. 26, 178-189.
    • Pasha, M., Hare, C., Hassanpour, A., Ghadiri, M., 2013. Analysis of ball indentation on cohesive powder beds using distinct element modelling. Powder Technol. 233, 80-90.
    • Pasha, M., Dogbe, S., Hare, C., Hassanpour, A., Ghadiri, M., 2014. A linear model of elasto-plastic and adhesive contact deformation. Granul. Matter 16, 151-162.
    • Savage, S.B., 1979. Gravity flow of cohesionless granular materials in chutes and channels. J. Fluid Mech. 92, 53-96.
    • Savage, S.B., McKeown, S., 1983. Shear stresses developed during rapid shear of concentrated suspensions of large spherical-particles between concentric cylinders. J. Fluid Mech. 127, 453-472.
    • Savage, S.B., Sayed, M., 1984. Stresses developed by dry cohesionless granular materials sheared in an annular shear cell. J. Fluid Mech. 142, 391-430.
    • Savkoor, A.R., Briggs, G.A.D., 1977. Effect of tangential force on contact of elastic solids in adhesion. P. Roy. Soc. Lond. Ser. A. Math. Phys. Eng. Sci. 356, 103-114.
    • Schulze, D. A new ring shear tester for flowability and time consolidation measurements, 1st International Particle Technology Forum, Denver, USA, 1994, 11-16.
    • Tabor, D., 2000. The Hardness of Metals. Oxford University Press, Oxford.
    • Tardos, G.I., Mcnamara, S., Talu, I., 2003. Slow and intermediate flow of a frictional bulk powder in the Couette geometry. Powder Technol. 131, 23-39.
    • Thornton, C., Yin, K.K., 1991. Impact of elastic spheres with and without adhesion. Powder Technol. 65, 153-166.
    • Wang, C., Hassanpour, A., Ghadiri, M., 2008. Characterisation of flowability of cohesive powders by testing small quantities of weak compacts. Particuology 6, 282-285.
    • Zhu, H.P., Zhou, Z.Y., Yang, R.Y., Yu, A.B., 2008. Discrete particle simulation of particulate systems: a review of major applications and findings. Chem. Eng. Sci. 63, 5728-5770.
  • No related research data.
  • No similar publications.

Share - Bookmark

Cite this article

Cookies make it easier for us to provide you with our services. With the usage of our services you permit us to use cookies.
More information Ok