A Ring Shear Tester as Calibration Experiment for DEM Simulations in Agitated Mixers – A Sensitivity Study

Mixing of bulk solids is an important unit operation in e.g. chemical, pharmaceutical and food industry. Simulating mixing processes with the Discrete-Element-Method (DEM) may help in both understanding and optimizing these processes. Since particle properties in a simulation within a realistic time-frame can currently not exactly resemble real material due to e.g. difficulties in representing the particle shape, the calibration of material properties for simulation of mixing processes is of utmost importance. A calibration of such parameters can compensate for differences between modeled and real particles. Without a proper calibration of the material parameters these simulations may not be representative for real mixing processes. Shear testers are generally well-suited for friction experiments such as static and rolling friction. In this work, a sensitivity analysis testing the influence of several material input parameters on the resulting tangential pre-shear stress is presented in the Schulze ring shear tester. The results show a dependence on the Young's modulus, the static and the rolling friction coefficients. Based on these results, a calibration methodology is proposed.