Experimental and numerical study of interaction between particle loaded fluid and a rough wall with micropillars

Abstract

Experimental and numerical studies of the behavior of a slurry in a shear flow over a rough surface with a defined micro-structure are presented. A new ring shear device was built which contains an optically transparent test chamber. Its bottom wall contains arrays of micro-cantilever force sensors simulating a defined surface roughness created by deep-etching of micro-pillars in a silicon wafer. The results of visual observation of the interaction of the suspension with the structured surface during severe deformation are shown. Observations comprise the liquid phase motion, i.e., the interaction between the liquid phase and solid particles, the movement of separate particles and their interactions with the micro-pillars. Abrupt changes in rotational motion and translational velocity of particles are observed that induce mutual collisions and successive formation and break-up of cluster structures of various types. In addition to the experiments the process was simulated with discrete element (DEM) simulations. Many characteristics found in the experiments are reproduced by the simulations. Furthermore the physical quantities of the process like contact forces or velocities can be quantified which helps us to develop more detailed models of the abrasive behavior of slurries.

A bending fluctuation-based mechanism for particle detection by ciliated structures

“…Surprisingly, the apparently simpler case of a non-adhesive particle interacting with a passive and isolated cilium has been less investigated. Non-adhesive particle/cilia interactions were probed in [37] but in the limit R 0 a. Severe deformations of the pillar assemblies are observed, that could lead to the rupture of the cilia.…”

A coupled lattice Boltzmann and fractal geometry method for laminar liquid flows

“…With rough walls described by a self-affine fractal, micro channel flows were studied by Liu and Ni (2009) to show that surface roughness affects not only velocity distribution, but also pressure distribution. Then, Mikulich et al (2015) presented the behavior of a slurry in a shear flow over a rough surface with a defined microstructure with an experimental and numerical method. Different fluid was also investigated to study the channel flow with a regular rough wall.…”

Numerical Investigation of Third‐Body Behavior in Dry and Wet Environments under Plane Shearing

“…Examples include the use of the DEM-CFD approach to model wear in pneumatic transport through pipe elbows [34], Couette flows in particle/fluid systems [35] or the interaction of structured surfaces with particle-laden flows [36].…”