Discrete element method study of the mixing and heat transfer behaviour of a binary‐size granular system in a rotating drum

Abstract Understanding the internal solid motion and heat transfer behaviour within rotating drums is paramount for their design and operation across various industries. The discrete element method (DEM) is utilized to elucidate the general flow, mixing, and heat transfer characteristics of particles within rotating drums. Following model validation, this study delves into the mixing behaviour and heat transfer patterns of binary‐size particles in the rotating drum, while also assessing the impact of size ratio and rotating speed. The findings reveal that variations in particle size result in noticeable radial segregation, consequently affecting the heat transfer dynamics of solid phase within the system. Higher rotating speeds enhance mixing and dispersion of solid phase but lead to a decrease in the averaged particle temperature. Furthermore, the heat flux exhibits a negative correlation with particle size. Distinct heat transfer behaviours are observed among particles of different sizes in both active and passive areas, with larger particle size ratios exacerbating segregation, potentially impacting final product quality. In summary, these findings offer crucial insights into heat transfer phenomena in rotating drums, aiding in the design and operation of apparatus.