Investigation of fibre-like shaped particles in a turbulent jet-in-crossflow channel flow configuration

Detailed experimental studies on the dispersion of non-spherical particles in different flow configurations, conducted in a test facility built around a horizontal closed water channel are presented. Specifically, a jet in cross-flow configuration was selected for measuring the dispersion of fibre-like particles injected through the small jet perpendicular into the developed horizontal channel flow. The glass fibres had a mean diameter of approximately 40 µm and aspect ratio with a modal value around 4. Experimental data were collected for different channel flow Reynolds numbers between 15,000 and 35,000 and a jet Reynolds number of 11,000. The motion and dispersion of non-spherical particles within the channel was analysed by a planar shadow imaging technique combined with Particle Tracking Velocimetry (PTV) for both, fibres and tracer particles. The discrimination between both phases was conducted on the basis of particle size and shape. The three selected channel flow velocities provided a jet being entrained more in the channel core as well as near the upper and lower channel walls. Therefore, also the interaction of the fibres with solid walls was of great interest. The collected experimental data were used for the validation of point-particle Euler/Lagrange numerical predictions including the required non-spherical particle transport and wall collision models. Special Attention was given to the treatment of the fibre-wall collisions using a hard-sphere model, modifying the post-collisional linear and rotational momentum. A reasonable good agreement with the experimental results was observed when the proper fluid modelling and fibre dynamics was included in the simulations.