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Scaling relations for granular flow in quasi-two-dimensional rotating cylinders
1Department of Chemical Engineering, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India. avorpe@che.iitb.ac.in
Summary
Particle flow in rotating cylinders forms a surface layer whose thickness increases with Froude number and particle size ratio. Material properties influence dynamic angle of repose but not surface profiles.
Area of Science:
- Granular physics
- Fluid dynamics
- Materials science
Background:
- Understanding granular flow in rotating systems is crucial for industrial processes.
- Previous models often simplify particle interactions and flow dynamics.
Purpose of the Study:
- To experimentally investigate the flow behavior of different granular materials in quasi-two-dimensional rotating cylinders.
- To analyze the influence of Froude number and particle size ratio on flow characteristics.
- To compare experimental results with existing continuum and heap models.
Main Methods:
- Flow visualization techniques were employed to study the movement of steel balls, glass beads, and sand.
- Experimental parameters included varying angular speed, cylinder radius, and particle diameter.
- Scaling analysis was performed on layer thickness and surface profiles.
Main Results:
- A distinct flowing surface layer and a fixed bed were observed.
- Scaled layer thickness increases with Froude number and size ratio.
- Surface and layer thickness profiles are material-independent but depend on Froude number and size ratio.
- Dynamic angle of repose increases with rotational speed and depends on particle properties.
Conclusions:
- Continuum models by Khakhar et al. accurately predict flow behavior across various parameters.
- Heap models provide reasonable predictions for interface angle profiles.
- Flow characteristics are largely independent of material type, suggesting universal scaling laws.