467558 DNS Simulation of Liquid Bridges Between Particles

Tuesday, November 15, 2016: 1:00 PM
Powell I (Parc 55 San Francisco)
Nikoletta Patsaki, RCPE, GmbH, Graz, Austria, Johannes G. Khinast, RCPE GmbH, Graz, Austria and Robert Scharler, Institute of Thermal Engineering, University of Technology, Graz, Austria


Liquid transfer within granular materials can result in alteration of the physical properties of the material due to the formation of liquid bridges between individual particles. Cohesive and viscous forces lead to complex and still not well understood granular behaviour. This can have a significant impact on various industrial processes such as coating, drying or granulation. Understanding how liquid is transferred in the micro scale between individual particles has been very challenging both experimentally and computationally [1].

The objective of the current work is the use of Computational Fluid Dynamics in order to:

1. Investigate the capillary forces due to the formation of a liquid bridge between a pair of particles.

2. Investigate the Viscous forces due to high wet particle collision velocities.

3. Develop a liquid transfer model applicable in larger scale particle simulations. Specifically we examine the liquid bridge rupture point and redistribution of the liquid on the involved particles, depending on liquid bridge volume, particle size ratio, liquid viscosity, surface tension and collison velocity.

The abovementioned microscale invastigation can be used as a tool for the development of closed form expressions that can be easily used in a macroscale DEM-CFD simulation of a fluidized bed agglomeration process.

REFERENCES:

[1] C.D. Willett, A.J. Simon, M.J. Adams, J.P.K. Seville, Pendular capillary bridges, In: in: A. Salman, M. Hounslow, J.P.K. Seville (Eds.), Granulation, Handbook of PowderTechnology, vol. 11, Elsevier, Amsterdam, 2007, pp. 1317–1350.

ACKNOWELEDGMENTS:

This work was supported by the TMAPPP Marie Curie Initial Training Network, funded through the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme under grant agreement No. ITN607453.


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