Micro-mechanics of wet solids in gas-solid contactors
Final Report Abstract
In a cooperation of the Institute of Solids Process Engineering and Particle Technology of the Hamburg University of Technology and the research group Multiscale Modelling of Multiphase Flows of the Eindhoven University the collision dynamics of wet particulate media was investigated. Therefore, wet particle – wall collisions were analyzed experimentally as well as numerically by force balances and DNS modeling, focusing on the influence of liquid, particle as well as impact properties on energy dissipation during the collisions. The experimental results indicate that energy dissipation in normal direction is highly influenced by the liquid layer and particle properties as well as by the normal collision velocity. Collision angle and initial rotation of the particle feature no effect on dissipation of kinetic energy in normal direction. In contrast, the liquid layer has only negligible influence on kinetic energy in tangential direction as well as on rotation of the particle after rebound. Instead, those are dominantly influenced by the frictional contact of the colliding surfaces, resulting in rebound dynamics of wet particles similar to dry particle collisions. The experimental results are summarized in an empirical equation predicting the influence of liquid layers and due to particle and collision properties on rebound dynamics. The force balance model, developed in this thesis, is based on often verified literature models of contact forces, gravitational forces, viscous and capillary forces. Having found good agreement between force balance model and experimental results, the force balance gives a physical model of collision dynamics. This allows a prediction of rebound behavior and additionally gives a deeper understanding of the physical principles of wet particle collision. The DNS model developed by our project partners at Eindhoven University of Technology is able to represent both the rebound kinetics of normal wet particle wall collisions as well as the shape of the capillary bridge between particle and wall. The empirical equation, the force balance and DNS model enable the prediction of wet particle – wall collision dynamics. Further studies have to show, if the same principles apply for particle – particle collision as well. This project already showed exemplary, that some additional parameters have to be accounted for such as different particle sizes, impact angles and initial rotation of both particles. However, first results for normal collisions also showed that the general dependencies seem to be similar.
Publications
- Oblique impact of particles on wet surfaces, Proceedings of the 7th International Granulation Workshop, Sheffield, Great Britain, July 1-3, 2015
B. Crüger, S. Heinrich, S. Antonyuk, N.G. Deen, J.A.M. Kuipers
- Coefficient of restitution for particles impacting on wet surfaces: An improved experimental approach, Particuology 25 (2016), 1-9
B. Crüger, V. Salikov, S. Heinrich, S. Antonyuk, V. Sutkar, N.G. Deen, J.A.M. Kuipers
(See online at https://doi.org/10.1016/j.partic.2015.04.002) - Collision behaviour of particles during normal and oblique impact on wet surfaces, Proceedings of the PARTEC 2016, April 19-21, 2016
B. Crüger, S. Heinrich, S. Antonyuk, N.G. Deen, J.A.M. Kuipers
- Collision dynamics of colliding wet solids: Rebound and rotation, Proceedings of Fluidization XV, May 22- 27, 2016
B. Crüger, Y. Tang, S. Heinrich, N.G. Deen, J.A.M. Kuipers
- Experimental study of oblique impact of particles on wet surfaces, Chemical Engineering Research and Design, 110 (2016), 209-219
B. Crüger, S. Heinrich, S. Antonyuk, N.G. Deen, J.A.M. Kuipers
(See online at https://doi.org/10.1016/j.cherd.2016.01.024) - Collision dynamics of wet solids: Rebound and rotation. Powder Technology, 316 (2017), 218-224
B. Buck, Y. Tang, S- Heinrich, N.G. Deen, J.A.M. Kuipers
(See online at https://doi.org/10.1016/j.powtec.2016.12.088) - Dynamics of wet particle-wall collisions: Influence of wetting conditions, Proceedings of the 8th International Granulation Workshop, Sheffield, Great Britain, June 28-30, 2017
B. Buck, Y. Tang, N.G. Deen, J.A.M. Kuipers
(See online at https://doi.org/10.1016/j.cherd.2018.05.014) - Interface-Resolved Simulations of Normal Collisions of Spheres on a Wet Surface, AIChE Journal 63(11) (2017), 4774-4787
Y. Tang, B. Buck, S. Heinrich, N.G. Deen, J.A.M. Kuipers
(See online at https://doi.org/10.1002/aic.15847) - Numerical investigation of collision dynamics of wet particles via force balance, Chemical Engineering Research and Design 132 (2018), 1143-1159
B. Buck, J. Lunewski, Y. Tang, N.G. Deen, J.A.M. Kuipers, S. Heinrich
(See online at https://doi.org/10.1016/j.cherd.2018.02.026)
