Subject area
Simulation of Fluids in Complex Geometries via Smoothed Particle Hydrodynamics Keywords
hot melt extrusion, mixing, smoothed particle hydrodynamics Staff
Univ.-Prof. Dipl.-Ing. Dr.techn. Johannes Khinast 
Dipl.-Ing. Andreas Eitzlmayr Duration
01. July 2012 - 30. June 2015

The entire project “Novel Approaches in Pharmaceutical Hot Melt Extrusion” is administrated at Research Center Pharmaceutical Engineering (www.rcpe.at). It includes the exploration of manufacturing possibilities for so-called “Nano Extrudates” by the addition of “Nano Suspensions” to a molten polymer matrix by Hot Melt Extrusion (HME) as well as the development of a novel approach for the simulation of fully filled and partially filled screws to establish better mechanistic understanding of mixing phenomena. The simulation part is conducted at the IPPT. The Smoothed Particle Hydrodynamics (SPH) Method offers high potential for the simulation of partially filled, complex shaped and rotating screw geometries. The mesh-less nature of SPH is very beneficial since the fluid domain in a twin screw is strongly deformed due to the rotation of the screws, which would require complicated remeshing techniques in conventional Computational Fluid Dynamics (CFD) methods. Moreover, SPH can inherently simulate free surface flows, which is the case in partially filled sections, and since it is funded on Lagrangian particles SPH is well suited to analyze mixing processes. Based on the open-source code LIGGGHTS (www.liggghts.com), which provides a flexible platform for particle based approaches, we are working on the development of required boundary conditions and rheological models. This should enable the characterization of the mixing performance of various types of screw elements used in HME via simulation, which leads to a better understanding of the underlying mixing mechanisms. Moreover, it offers the possibility to analyze different screw configuration variants of a mixing section in detail, which constitutes a step towards future engineering tools for process development. Project Partners
Leistritz Extrusionstechnik GmbH
Research Center Pharmaceutical Engineering GmbH Sponsored By
Austrian COMET Program by the Austrian Federal Ministry of Transport, Innovation and Technology (BMVIT) and the Austrian Federal Ministry of Economy, Family and Youth (BMWFJ). Also funded by the State of Styria (Styrian Funding Agency SFG).