Modelling & Simulation


Development of a modeling framework for the gas-phase synthesis of nanomaterials

Patrick Wollny, University of Duisburg-Essen, Duisburg, Germany
Irenäus Wlokas, University of Duisburg-Essen, Duisburg, Germany
Andreas Kempf, University of Duisburg-Essen, Duisburg, Germany

Nanomaterials from the gas phase show unique properties like high purity and large specific surface area [1]. Gas phase processes are simple, continuous and scalable. However, the scaling from the lab to the pilot or even industrial size requires simulation and a deep understanding of the physics/models, as the similarity parameters cannot be kept constant during the up-scaling of the processes.

We present the development of a simulation framework based on the open-source computational fluid dynamics (CFD) library OpenFOAM [2]. In our approach, the particle dynamics (nucleation, agglomeration and sintering) are described by a simple monodisperse model [3] locally solved for Lagrangian particle parcels transported through the (turbulent) flow field. The flow of the chemically reacting gas phase is described in the Eulerian frame using numerical methods and models already present in the OpenFOAM library. In a first step, the model is tested and validated for simple configurations which allow to discriminate the impact of different physical effects on the mean particle number, volume and area concentrations. Subsequently, the application for simulation of the pilot-scale synthesis process is demonstrated. The physical object of our investigation is a pilot-scale wall heated reactor for the synthesis of high-purity silicon particles from the thermal pyrolysis of silane, operated in the labs of the Institut für Verbrennung und Gasdynamik (IVG) at the University of Duisburg-Essen

The work is supported by the European commission in the Horizon 2020 framework, project Nanodome (reference: 646121).

[1] A. Lorke, M. Winterer, R. Schmechel, C. Schulz, C. (Eds.), Nanoparticles from the gasphase: Formation, structure, properties, Springer Science & Business Media (2012).
[2] H.G. Weller, G. Tabor, H. Jasak, C. Fureby, A tensorial approach to computational continuum mechanics using object-oriented techniques, Computers in physics, 12(6) (1998) 620-631.
[3] F.E. Kruis, K.A. Kusters, S.E. Pratsinis, B. Scarlett, A simple model for the evolution of the characteristics of aggregate particles undergoing coagulation and sintering, Aerosol science and technology, 19(4) (1993) 514-526.

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