Size segregation of disk particle in two-dimensional chute

Area of Science:

• Granular physics
• Particle dynamics
• Computational fluid dynamics

Background:

• Particle segregation and stratification are critical phenomena in granular flows.
• The underlying mechanisms of size segregation, particularly in disk-shaped particles, remain incompletely understood.
• Chute flows provide a relevant system for studying segregation dynamics.

Purpose of the Study:

• To investigate the size segregation behavior of two-component disk particles in chute flows.
• To elucidate the dominant segregation mechanism and its influencing factors.
• To develop a physical model for the observed segregation process.

Main Methods:

• Utilizing the discrete element method (DEM) for numerical simulation.
• Analyzing the forces acting on large disk particles during segregation.
• Systematically varying parameters such as particle size ratio (η), density (ρ), static friction coefficient (μ), and chute angle (α).

Main Results:

• The 'squeeze expulsion' mechanism was identified as the primary driver of size segregation in this disk particle system.
• Simulation results demonstrated the significant influence of particle size ratio, density, friction, and chute angle on segregation.
• A physical model for the 'squeeze expulsion' mechanism was successfully established.

Conclusions:

• The 'squeeze expulsion' mechanism is fundamental to the size segregation of disk particles in chute flows.
• Understanding the conditions for 'squeeze expulsion' provides insights into controlling granular stratification.
• This research contributes to a deeper comprehension of granular flow dynamics and segregation.