(381b) Top-Bottom Method for the Calibration of DEM Simulation Based on a Set of Complementary Measurements.

DEM simulations are useful to predict the behaviour of powders and granular materials inside industrial processes. Conceptually, two methods can be used for the calibration of DEM simulation parameters. The first method is a bottom-up approach based on the direct measurement of the microscopic parameters at the scale of the contacts between the grains. Even if this bottom-up method makes sense conceptually, it is often practically impossible to use this approach based on complex measurement. The distribution of grain size and shape in real powders leads to strong fluctuations of the results. In addition, in many simulation models, the input parameters are not rigorously linked with these physical parameters.

We propose an alternative top-bottom method based on a set of macroscopic measurements that can be used practically without difficulties to calibrate the simulation. The principle consists in measuring the powder properties in a laboratory and afterward to simulate the same process to tune the simulation parameters following an optimisation process. These measurements are performed in well-known geometries (tubes or rotating drum) and can be easily simulated. Finally, the best set of parameters will be used to simulate a complex industrial process for example.

As for any powder characterisation task, the measurement geometry and the stress applied on the sample must be selected in accordance with the application. For a process involving high speed powder flow with a low confinement, the rotating drum methods (GranuDrum) will extract parameters that make sense for the application. On the other side, the flow through an aperture method (GranuFlow) provides a simple and quick classification of flowability. In between, the optimised GranuHeap angle of repose measurement is a good compromise. In this work, we demonstrate the potential applications of digital twins of these widely used powder characterization devices.