The research consists of two parts. In the first part, the development of a novel, fully Lagrangian particle-fluid modelling framework applicable to systems with many particles in a wet environment is performed. For modelling the particles, the Discrete Element Method (DEM) is employed. For the fluid part, the Lagrangian Smooth Particle Hydrodynamics (SPH) is used which enables handling free surfaces and large movements of the fluid, inherently. While unresolved fluid flow around particles is already used in mesh-based methods, coupling the DEM and SPH in one computational framework is a challenging task addressed in this project. In the first part of the project, a framework was developed for representing technical scale systems with many particles in a wet environment.
A comparative study on mesh-based and mesh-less (SPH) coupled CFD-DEM (Computational Fluid Dynamics – Discrete Element Method) methods to model particle-laden flow was performed. In general, results obtained using both approaches agreed well with analytic reference results. Numerical differences were found mostly due to difference in computed fluid fractions that result in different drag forces. The proposed new model to account for boundary conditions in the SPH approach was demonstrated to produce accurate results in the presented verification tests. They proved to be convenient and stable in the context of DEM-SPH simulations.
In the second part of the project, the developed framework was applied to the modelling of a wet separation process involving a sink-float drum separator for plastic recycling. The numerical analysis of polyethylene terephthalate (PET) particle separation from polypropylene (PP) particles in the rotating drum was performed. The influence of different operational and design parameters, such as the rotational velocity, the number of lifters, the feed rate etc., was analysed. Numerical results show, that the use of the separating vertical walls, lower rotational velocity, higher number of the lifters and the higher feed velocity by water increases the purity of the separated particles.
Dissemination of the results:
1) Published paper in a journal:
D. Markauskas, H. Kruggel-Emden, R. Sivanesapillai, H. Steeb. Comparative study on mesh-based and mesh-less coupled CFD-DEM methods to model particle-laden flow. Powder Technology. 305 (2017) 78-88.
A version of the final peer-reviewed manuscript accepted for publication is available on arXiv.org: arxiv:1603.06808
2) Presentation of the results in a conference:
Talk: Numerical analysis of wet separation of particles by density differences. Presenter: D. Markauskas, Co-author: H. Kruggel-Emden. 14th International Conference of Numerical Analysis and Applied Mathematics, ICNAAM 2016, 19-25 September 2016, Rhodes, Greece.
3) Accepted manuscript for publication in a conference proceeding:
D. Markauskas, H. Kruggel-Emden. Numerical analysis of wet separation of particles by density differences. Proceedings of 14th International Conference of Numerical Analysis and Applied Mathematics, ICNAAM 2016, 19-25 September 2016, Rhodes, Greece, 4 p.
A version of the final peer-reviewed manuscript accepted for publication is available on arXiv.org: arxiv:1609.08421
4) Submitted manuscript for publication in a journal:
D. Markauskas, H. Kruggel-Emden, V. Scherer. Numerical study of wet plastic particle separation using coupled DEM-SPH method. Manuscript is submitted for the review in the journal Powder Technology.
