Single Granule Friction and Wear Investigations

Understanding granular flows has always been important for predicting natural phenomena such as avalanches, rockslides, and soil erosion, as well as industrial processes such as coal-based fossil fuel systems, solids processing, and food manufacturing. As such, it becomes important to understand granular flows from both a classical granular flow and tribological perspective. Inherently important in the study of granular flows is the study of the individual particle level interactions, which in turn define the global behavior of the flow. An essential interaction parameter is the coefficient of friction (COF). The fidelity of discrete models hinge on the accuracy of particle-level physics defined by parameters such as COF (and COR). This work aims to study the COF and associated wear and surface metrology of individual granules sliding against a rotating disk at varying speeds and loads. The video shows an attrition experiment of a granule wearing under a prescribed speed and load.

PFTL Research Assistant(s):   Martin C. Marinack Jr.; Patrick S. M. Dougherty; Deepak C. Patil
Method(s) Employed:   High Speed Video, Optical Interferometry, High/low speed and load tribometry, in situ data acquisition
Rig(s) and/or Software(s) Employed:   In-house Granule-on-Disk Tribometer, Bruker UMT-3 Tribometer, Zygo New-View 7300 Optical Interferometer
Sponsor(s):   NSF Graduate Research Fellowship

Sample Results:

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Select PFTL References:

(1) Marinack Jr., M.C., Dougherty, P.S.M., Higgs III, C.F., 2012, "Single Particle Interaction Properties: Investigations on the Coefficient of Restitution and Coefficient of Friction," Proceedings of the ASME/STLE International Joint Tribology Conference 2012, Denver, CO.

(2) Marinack Jr., M.C., Dougherty, P.S.M., Higgs III, C.F., 2012, "Experimental Investigations on the Coefficient of Friction and Wear of Single Granules," STLE Annual Meeting and Exhibition 2012, St. Louis, MO.