Particles falling through viscoelastic non-Newtonian flows in a horizontal rectangular channel analyzed with PIV and PTV techniques

Fall velocity of particles traversing through viscoelastic non-Newtonian flow in a horizontal channel was measured. Aqueous solutions of Poly-Anionic Cellulose (PAC) with two different concentrations 2 and 4 g/l were used as a continuous liquid phase. An experimental setup with a rectangular test section was carried out to achieve good optical conditions. Particle image velocity (PIV) and particle tracking velocity (PTV) techniques were used to measure fluid velocity, particle trajectories as well as particle fall velocities. Experiments were also performed for Newtonian fluid (water) as a reference fluid. It was found that the particle fall dynamics is closely related to the fluid rheology as well as the local fluid velocity, shear rate and particle size. The more concentrated the PAC solution the stronger is the drag coupling, and with less spread in particle trajectory. The experimental results were compared with 3D CFD simulations. The effect of parameters which influences the hole cleaning aspects on model prediction was investigated and developed a correlation to predict the settling impingement distance of the particles.