A new drag model for bidisperse particle agglomerates

Particle agglomeration is a common phenomenon in natural and industrial environments. This study investigates the motion characteristics of bidisperse agglomerates in Stokes flow and introduces a novel drag model that explicitly incorporates particle number and size ratio as critical parameters. By analyzing the effects of agglomerate structure, particle number, and size ratio on settling behavior and drag force, we demonstrate that agglomerate orientation is determined solely by geometric structure, while drag force is primarily influenced by particle number and size ratio, with minimal impact from structure. The proposed predictive model for the drag correction coefficient offers enhanced accuracy and scalability compared to existing models, as validated with polydisperse agglomerate data. This study provides a simplified yet comprehensive approach for predicting polydisperse agglomerate behavior, offering significant theoretical and practical implications for engineering applications in granular flows.