FLUID – Simulation Software for Complex Fluids

Digital Twin for Complex Flow Processes of All Kinds

FLUID is our extremely robust flow solver that correctly calculates especially complex rheologies (deformation and flow behaviour of substances) of multiphase flows (miscible and immiscible) in and around porous media. Thus, the software is used to simulate and optimise manufacturing and processing processes of polymers, particle and fibre suspensions, foams, concrete and much more.

To be able to provide simulation solutions for such a wide range of materials and physical effects, we have developed FLUID to ensure the rapid implementation of new rheological models and their robust and efficient solution of any multi-physics systems for industrial applications.

With FLUID you can model, simulate and optimise the following fluid dynamic processes, among others:

  • Injection moulding, extrusion and sheet compression moulding of fibre-reinforced materials.
  • Filling, emptying, sloshing of tanks and containers
  • Potting simulation of electronic components
  • Electrolyte filling of porous battery cells
  • Simulation of expanding PU foams (polyurethane foams) with FOAM
  • Flows with bulk solids with GRAIN 
  • Powder injection moulding with particle migration
  • Flow simulation of concrete

Our Software FLUID:

  • enables easy and fast implementation of individual rheological models
  • robust coupling of additional physical effects such as temperature, concentration equations, reactions, fibre orientation, etc.
  • includes a user-friendly graphical interface
  • offers an integrated pre-processing tool for CAD-3D data
  • allows interactive post-processing
  • uses multi-core computer technology and runs on Windows and Linux operating systems

Simulation of Injection Molding Processes for Fiber Reinforced Materials

The fiber reinforcement of polymer materials is a very important technique in the production of lightweight construction materials. The potential of these materials can only be exhausted if the fiber direction during the production process can be predicted with high precision.

The software FLUID implements a highly developed, physically based modeling method that takes account not only of the influence of the flow on the fiber concentration and orientation, but also the return of the fiber concentration and orientation to the rheological behavior of the suspension.

Injection molding simulation of polymeric material with 30% glass fiber content.

Simulation Example: Injection Molding Simulation of an Airbag Housing

Spatially resolved information about locally existing:

  • pressure
  • velocity
  • fiber orientation
  • fiber concentration
  • Spread of the flow front
  • fluid temperature

Simulation of Non-Newtonian Multi-Phase Flows

By FLUID, simulations of non-Newtonian fluids, e.g. In microstructures, which are complex, three-dimensional geometric structures of porous materials. The structures simulated by us can be used directly from computer tomographs or generated with the software GeoDict®.

Such simulations help to understand and identify the relations between the fluid velocity, pressure, viscosity and permeability of the medium. The effective permeability law can be used in macrocale simulations in which the porous structure is only a subset of an overall geometry configuration.

© Fraunhofer ITWM
Mikrostruktur Simulation von Nicht-Newtonschen Mehrphasenströmungen

Simulation Example: Infiltration Process of a Non-Newtonian Fluid into a Microscale-Resolved Rock Structure

Spatially resolved information on the Porenskala about:

  • pressure
  • velocity
  • temperature
  • Spread of the flow front
  • Effective permeability tensor

Example Projects


Characterization and Modelling of Thermoplastics

We contribute our simulation expertise to the AiF project.


ProZell Project Cell-Fi

The project Cell-Fi deals with speeding up the electrolyte uptake through optimized filling and wetting processes.


Potting Process Simulation of Electronic Devices

In the project SOVEB we simulate this process with FLUID so that companies can optimize their production steps.


EU-Project ALMA

ALMA’s ambition is to develop a new type of battery-electric vehicle structure for passenger cars. The aim is to reduce the weight of the vehicle structure by up to 45 percent.