Effect of vibration characteristics on the performance of mixing in a vertically vibrated bed of a binary mixture of spherical particles

The uniform mixing is necessary in many processes such as those used in pharmaceutical, chemical and petrochemical industries. The present work studies the influence of vibration characteristics on mixing of binary mixtures of spheres produced in a vibrationally fluidized bed by using discrete element method. Solid-like flow pattern was observed in low frequencies and amplitudes, while as the vibration got stronger, particles behaved fluid-like, and convection rolls were generated. The generation and movement of convection rolls played a fundamental role in mixing within vibrated beds. It was realized that mixing was generally improved by increasing the vibration amplitude. In contrast, an optimal frequency was found in each amplitude, by which the best mixing occurred. The particles average velocity always increased by amplitude at a fixed frequency, while the mixing was not necessarily improved. It was found that the results were in qualitative agreement with some previous experimental and numerical studies. (C) 2019 Elsevier Ltd. All rights reserved.