(756b) Calibration of Particle Properties for Multilevel/Adaptive Coarse Grained DEM Simulations

Calibration of particle properties for DEM is an important area with many open questions and unresolved issues. One of the ways to obtain the particle properties for DEM is bulk calibration[1]. In this method, DEM simulation results are matched with a set of experimental observations such as dynamic and static angle of repose, hopper discharge rate etc. to obtain the best fit values of the parameters. However, most of the studies are aimed at calibrating the actual particle properties, and literature on property calibration of coarse-grained particles is sparse. In this work we will address this research gap by designing a calibration methodology for the recently developed multilevel/adaptive coarse-graining technique [2]. In this technique the coarse-graining ratio of a particle changes dynamically during its course of motion through the equipment, unlike a more commonly used constant coarsegraining ratio.

In this presentation, we will first discuss the relation between the microparameters of the resolved particles and that of the coarse-grained particles. We will show a study that explores various force scaling, like that discussed by Sakai et al. [3], and demonstrate their effect on the final model outcome. The scaling for other microparameters such as particle density, particle to wall friction etc. will also be discussed. Finally, a systematic method will be demonstrated which can be used for calibration of the particle properties at various zones of an adaptive coarse-grained simulation. A tablet die feeder and a screw feeder will be used as two examples

References:

1. C. Coetzee, “Calibration of the discrete element method,”, Powder Technology, vol. 310, pp. 104–142, 2017
2. (320b) A Multi-Level Coarse Graining Technique for Discrete Element Method (DEM) Simulation. Jayanta Chakraborty, Tarun De, Jitendra Kumar, Salvador García-Muñoz, Maitraye Sen. AIChE Annual Meeting, 2020.
3. M. Sakai and S. Koshizuka, “Large-scale discrete element modeling in pneumatic conveying,” Chemical Engineering Science, vol. 64, no. 3, pp. 533–539, 2009