Modeling dust dispersion and suspension pattern under turbulence

Abstract

Controlling dust generation and minimizing volumetric dust concentration, within confined space, are key to the prevention of dust explosion. Dust dispersion pattern under pressure, such as primary explosion or dust leakage from equipment, can be simulated using unsteady state computational fluid dynamics – discrete phase models (CFD-DPMs). Although they offer computational efficiency, DPM simulations do not incorporate particle-wall or particle-particle interactions. In this paper, we therefore adapt the model to include particle-wall interaction based on energy conservation. In a confined volume, to experimentally observe the dust dispersion pattern, a theoretical concentration of 0.05 and 0.10 kg/m3 was generated and the turbulence was created with airflow of 2 and 10 m/s using an air compressor. Similar conditions were used to model the dust dispersion pattern. Our findings show that the dust concentration inside the confined chamber is not evenly distributed throughout its entirety and that explosive dust cloud concentration only takes up to 37.8% of a chamber's volume for a 0.10 kg/m³ injected dust concentration at 10 m/s air velocity. With a decrease in the dust injection rate and air velocity, the dust cloud volume decreased due to lesser amount of particles and low kinetic energy. This study presents an efficient dust dispersion modeling method, and the result shows the dust cloud volume is highly dependent on the dispersion velocity. The predicted dust concentration and the experimental results indicate that this boundary corrected CFD-DPM modeling approach is suitable for dilute particle dispersion flow, where the volume fraction of particles is lower and the adhered particles only form a single particle layer on the wall boundary.