An experimentally validated DEM study of powder mixing in a paddle blade mixer

An investigation on the predictive capabilities of Discrete Element Method simulations of a powder mixing process in a laboratory scale paddle blade mixer is presented. The visco-elasto-plastic frictional adhesive DEM contact model of Thakur et al. (2014) was used to represent the cohesive behaviour of an aluminosilicate powder in which the model parameters were determined using experimental flow energy measurements from the FT4 powder rheometer. DEM simulations of the mixing process using the contact model parameters were evaluated against the experimental measurements of the mixing rate. The results demonstrated that whilst the DEM model is capable of reproducing the FT4 flow energy of the powder to an excellent agreement, the simulations of the mixing process produced a qualitative agreement on the trend of the mixing rate in the experiments for both dry and wet powders. The mixing was under-predicted in the simulations, suggesting that flow energy measurements alone may not be sufficient for the optimization of a DEM model of powder mixing. (C) 2017 Elsevier B.V. All rights reserved.