Paper: Particle entrapment in line elastohydrodynamic contacts and the influence of intermolecular (van der Waals) forces.
Author: George K. Nikas
Published in: Lubricants, 2020, 8(5), article 60 (open access)
A metallic particle passing through concentrated rolling-sliding contacts is often linked with surface damage for particles larger than the available gap. At the instant of particle pinching, force balancing dictates particle entrapment and passing through the contact or rejection. It is vital to include all major forces in this process. This study revisits the analytical entrapment model previously published by the author for spherical micro-particles by incorporating a force so far overlooked in related studies, namely the van der Waals intermolecular force and, additionally, surface roughness effects. In conjunction with particle mechanical and fluid forces, this provides an almost complete set to use for correct force balancing. A parametric analysis shows the effect of several geometrical, mechanical, rheological and surface parameters on spherical particle entrapment and reveals the significance of the van der Waals force for particles smaller than about 5-10 microns in diameter.
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