Centrifuge Study on Influence of Particle Size, Compression and Substratum on Particle-Surface Adhesion Force

Abstract

The centrifugal technique was used to investigate the influence of particle size, applied compression and substrate materials (stainless steel, glass, Teflon® and PVC) on particle-surface adhesion force. Phosphate rock and manioc starch particles were used in a microcentrifuge that contained specially designed centrifuge tubes and reached a maximum rotation speed of 14,000 rpm. The profile of adhesion force followed a log-normal distribution and adhesion force increased linearly with particle size and the increment of the compression force. The manioc starch particles presented adhesion forces greater than those for the phosphate rock particles for all particle sizes studied. The glass substrate showed a higher adherence than other materials, most probably due to its hardness and polishing.

Studies on detachment behavior of micron sized droplets: A comparison between pure fluid and nanofluid

“…Though all the experiments were carried out with glycerol solution of the same fluid properties, they showed different depositing properties on different surface materials due to the change in surface properties such as surface roughness. A rough surface could decrease the adhesion between a solid particle and the surface due to the decrease of contact area by the effect on the separation behavior of the particles adhering to the substrate surface (Zimon 1982;Takeuchi 2006;Felicetti et al 2008). Petean and Aguiar (2015) found that the adhesion increases when the roughness increases after a press-on force applied on the microcrystalline cellulose particle, which caused a plastic deformation between asperities and the particle, thus increased the real contact area.…”

“…The detachment behavior of micron size liquid droplets under a constant and directional force field generated by a centrifugal method was investigated. A centrifugal method was used because its techniques are fully developed and are commonly used for determining the adhesive force between particles and a surface (Salazar-Banda et al 2007;Felicetti et al 2008). For normal force, liquid droplets, unlike solid particles that resuspended completely as long as the removal force equals or is greater than the adhesion force (Hinds 1999), are removed by portion as long as the applied centrifugal force exceeds a certain threshold, which is called a critical value and this point is closely related to the contact diameter of droplets (Leung et al 2013).…”