Granular and Bulk Flow Simulation

Granular materials and the associated processing processes are highly significant to the economy and, at the same time, they are an exciting area of research in the simulation of complex fluids. Approximately 60 % of the products in the chemical industry are granular materials – another 20 % of the products contain powdered forms.

GRAIN – Granular and Bulk Flow Simulation

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.


  • 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


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


Further Publication

Latz, A., Schmidt, S. (2010). Hydrodynamic modeling of dilute and dense granular flow. Granular Matter, 12(4), 387–397.