Modelling of the dust release from bulk solids in the event of particle impact through enhanced dust detachment functions

Abstract

In terms of environmental, health and explosion protection, it is important to assess the extent of diffuse dust emissions. In addition to standardized dustiness tests and measurements under field conditions on real dust emissions, numerical methods such as the Discrete Element Method (DEM) coupled to Computational Fluid Dynamics (CFD) are promising approaches for the prediction of the latter. Thereby the DEM calculates the bulk solid particle motion and the CFD provides information about the flow parameters of the fluid phases in terms of location and time. Due to computing time restrictions when simulating larger processes, each dust particle is usually not modelled in detail, but rather described using so-called dust detachment functions. In this study, detachment functions are adapted and developed based on a benchmarking with dust-resolved DEM simulations. Therefore, the adhesive contacts of fine dust particles attached to coarse bulk solid particles are modelled with an adhesive contact model (JKR approach). Depending on the bulk particle velocity, impact angle, material properties and bulk particle rotation in the case of single particle-wall and single particle-particle contacts, a good match between dust-resolved DEM and DEM with integrated detachment functions can be provided. For the further derivation and verification of the method, it is planned to compare numerical results also to experimental investigations. Therefore, the fine dust particle amount is reproducibly applied to coarse bulk solid particles by a well-defined calcium carbonate powder. The adhesion of the powder phase is then analysed before and after an impact.