Fraunhofer-Institut für Techno- und Wirtschaftsmathematik ITWM

Many innovative products are based on materials that have a complex rheological behavior during production. Known examples of such materials are polymer-based liquids, particle and fiber suspensions, foams, concrete and much more.
In order to be able to find simulation solutions for such a range of materials used in industrial applications, we offer the simulation infrastructure FLUID, which is based on the software platform CoRheoS - Complex Rheology Solvers. CoRheoS enables the rapid implementation of new rheological models and their robust and efficient solution for industrial application problems.
Software Platform CoRheoS

• Validated, documented, graphical software
• Preparation of CAD data, 3D Postprocessing
• Use of Multicore Computing
• Runs on Windows and Linux

Services and simulation examples:

• Numerical simulation of complex rheological flows and multiphase flows
• Injection molding and extrusion of fiber-reinforced materials
• Powder injection molding process with particle migration
• Flow simulation of concrete
• Simulation of expanding PU foams
• Infiltration Process of a Non-Newtonian Fluid into a Microscale-Resolved Rock Structure
• Coupling with granular flow simulation GRAIN
• Fast implementation of user-defined rheological models
• Simulation-based, scientific advice for industrial flow problems with complex material behavior

The Complex Rheology GRAIN Solver is developed to deal with the flows of granular materials (for example sand). To deal with industrial problems two competing goals have to be met:

• The whole range of the complex three dimensional dynamic behaviour of granular flow has to be reproduced as realistic as possible.
• The computation time must be short enough for the use in an industrial environment.

Both requirements are best fulfilled by using a special nonlinear hydrodynamic model, which has been developed at the ITWM. Our hybrid model combines the characteristics of rapid granular flow with approaches from soil mechanics for dense slow flows. It reproduces known results from granular dynamics as e.g. dilatancy, existence of shear bands and solid like behaviour.
This model and appropriate numerical methods (i.e. several nonlinear finite volume methods) are implemented in GRAIN  – a module of the CoRheoS software platform. From the reading of arbitrary geometries to the visualisations, GRAIN is able to cover the simulation of granular flows.
Advantages over other Methods
An important advantage of GRAIN in comparison to particle-based methods like DEM is the treatment of the granular material as a continuum. This enables the simulation of both slow and fast granular processes with industrially-relevant material volumes and realistic particle sizes of different granulates and powders in the customary CFD context with similar computation times.
The microscopic interaction of particles becomes part of the continuum modelling here. In addition, the parallelisability of CFD processes can be achieved very effectively and is intensively investigated. These results can be applied directly to the method in GRAIN for the further reduction of simulation times.
Interaction of Moving Components
In the past year the application field for GRAIN was greatly expanded once again by the interaction of moving components with granular media. Building on the initial success of promising testing, an industrial project for the simulation of mixing machines with rapidly moving components was successfully completed.
Application and Project Examples

• Simulation of mixing processes and devices
• Simulation of agitator bead mills
• Simulation of silos

Services:

• Spatially resolved dynamic 3D simulation of
  • granular bulk flow processes
  • two and three-phase fluid-driven granular flow processes
  • mechanically driven mixing and milling processes
• Virtual testing of design, upscaling, flow patterns and residence time distributions.
• Project-based collaborations and scientific consulting for
  • Material characterization targeted towards simulation in collaboration with Fraunhofer IKTS
  • Modeling extensions to customer-specific process conditions
  • On-Site licensing, installation and running of the software

Partners

• AG Pulvertechnologie at Fraunhofer IKTS
• Chair of Process Technology of Dispersed Systems (VDS) at TU Munich
• Projet PELIGRIFF IFPEN Lyon

MAVI comes with a set of algorithms enabling the segmentation of three dimensional image data of powders and particles. Common questions e.g. regarding the shape or size distributions of these objects can be addressed. Length, width, and height of complex shaped particles can be derived robustly from the edge lengths of the minimal bounding cuboid.
In the ZIM project "Development of innovative high performance grout based on the criteria of grain shape through new 3D image data measuring and analyzing techniques" the Fraunhofer ITWM develops algorithms for a robust and as far as possible automatic extraction of the compound's important parameters from 3D image data.

MAVIparticle

• generalises size and shape features from 2D particle analysis unambiguously to the spatial setting.
• allows the complete analysis of large 3D gray scale data including automatic visualization
• is particularly suited for characterising residual dirt particles in technical cleanliness applications. Dangerous dirt particles can be detected reliably and with high throughput based on 3D images obtained by micro computed tomography.

MAVIparticle Features

• intrinsic volumes (volume, surface area, mean width, Euler number)
• isoperimetric shape factors
• mean gray value
• length, width, and thickness
• maximal Feret diameter
• maximal local thickness
• elongation and elongation index

Partner

• RJL Micro & Analytic