Clogging of soft particles in two-dimensional hoppers

Area of Science:

• Physics
• Materials Science
• Fluid Dynamics

Background:

• Particle flow through hoppers is crucial in various industrial processes.
• Previous studies often used hard particles, potentially overlooking the role of softness in clogging dynamics.

Purpose of the Study:

• Investigate the clogging behavior of soft particles in quasi-two-dimensional hoppers.
• Determine the influence of particle softness and gravitational force on hopper flow and clogging.

Main Methods:

• Conducted experiments using oil-in-water emulsion droplets and hydrogel particles in thin sample chambers.
• Employed simulations to model particle flow and clogging phenomena.
• Varied gravitational force by changing the tilt angle of the sample chamber.

Main Results:

• Clogging in soft particle systems occurs with hopper openings only slightly larger than the particle diameter.
• Reduced gravity facilitates clogging, allowing it to occur for larger hopper openings.
• Particle softness, quantified by the fractional deformation under weight, is a key factor controlling clogging.

Conclusions:

• Particle softness significantly impacts clogging behavior in hoppers, a factor often neglected in hard particle studies.
• The fractional deformation parameter effectively unifies data from simulations and experiments with soft particles.
• Findings suggest that hard particle studies may not accurately represent clogging in soft matter systems.