Contact heating of bi-dispersed milli-beads in a rotary drum. Mechanical segregation impact on temperature distribution and on heating kinetic analyzed by DEM simulation

• Published in: Powder technology 2019-09, Vol.354, p.240-246
• Main Authors: Mesnier, A., Rouabah, M., Cogné, C., Peczalski, R., Vessot-Crastes, S., Vacus, P., Andrieu, J.
• Format: Article
• Language: English
• Subjects: Baffles; Beads; Bi-dispersed bed; Chemical and Process Engineering; Chemical engineering; Chemical Sciences; computer software; Contact heat transfer; DEM simulation; Discrete element method; drums (equipment); Engineering Sciences; Heating; Heating rate; particle size; Particulate solid; powders; Rotary drum; Segregation; Simulation; Standard deviation; temperature; Temperature distribution
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2019.05.059

Mechanical and thermal particulate interactions within beds composed of milli-metric size spherical beads rotated and heated by contact in a horizontal drum were simulated by means of commercial discrete element software EDEM. Mono-dispersed, gaussian-dispersed and bi-dispersed beds (two particle sizes or two particle densities) were considered. The mechanical segregation index (standard deviation of local bed compositions), the standard deviation of beads temperatures and the thermal segregation index (normalized standard deviation) were calculated for the four types of bed and for different baffles configurations. According to the simulations results, the temperatures dispersion was enhanced by the mechanical segregation and reached its highest values for the bi-density bed. Increasing the number and the length of the baffles considerably improved the overall heating rate and the thermal homogeneity of the considered beds, but influenced less the mechanical segregation within them. [Display omitted] •Mechanical and thermal segregation occur in rotated and heated bi-dispersed beds.•Mechanical segregation enhances considerably the thermal dispersion for a bi-density bed.•Thermal dispersion is reduced by increasing the number and length of the baffles.•Thermal kinetic depends on the bed morphology and is the highest for the bi-size bed.•Overall heating rate is improved by increasing the surface area of the heated baffles.