Hochschule Karlsruhe Hochschule Karlsruhe - University of Applied Sciences
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Hochschule Karlsruhe Hochschule Karlsruhe - University of Applied Sciences

Institute for Digital Materials Research


Examples of microstructure simulations are given under the following thematic headings.

Microstructure formations in multiphase systems

Simulation of the formation of a three-phase eutectic microstructure.
Middle: Representation of the three phases.
Left: Ag2Al phase (green) and right: Al2Cu phase (blue). The Al phase is shown in red.

Cellular structures

Temperature distribution in an open-pored metal foam.

Heat and mass transfer

Numerical methods (CFD, phase field)

Numerical methods are an efficient tool for predicting physical
processes. processes. CFD (Computational Fluid Dynamics) is a method for the numerical solution of Navier-Stokes equations to describe flow processes and the associated heat and mass transport. Flow processes play a major role in almost all technical applications. Whether flow-through or flow-around tasks: fluid mechanical problems are in demand across all industries. They can be found, for example, in the basic problem of determining the pressure loss for the design of fans and pumps or in the basic problem  of calculating an adjusting volume flow distribution.

CFD for industrial practice

Often, coupled problems exist in practice, where, for example, a pressure load on structural bodies arises due to a flow or heat is transferred to the structural body.
Here it is necessary to combine the calculation types. Newer CFD methods already offer coupled solvers in order to calculate the coupled processes simultaneously within one solution process. Especially in connection with coupled physical processes, thermally dominated applications are becoming increasingly apparent in the industrial context. These are particularly relevant in the fields of electronics, semiconductor technology and optics. In this context
miniaturised cooling concepts using innovative, often research-based materials such as foam structures, textiles, membranes, microchannels and heat pipes are in demand. In addition, solutions for heat storage and improvements in heat transfer effects through targeted two-phase flow processes are of high interest.

CFD for Research 

The FD department of the IDM research institute focuses on multiphysics application fields and uses its own solvers (PACE3D, the phase field method and the Navier-Stokes method) as well as commercial software (StarCCM+) for this purpose in addition to open source solvers (OpenFoam)

Through this spectrum of solution methods, both industry-related tasks and tasks from applied research can be processed. Particularly in the case of research-related tasks, the focus of the work is on model extension in the environment of multiphase systems. Microstructure simulations are of particular importance here, in which porosities (cellular structures), for example, are completely resolved for the calculation. Cellular structures are used in a variety of industries, including medical technology (membranes), environmental technology (filters) and automotive (fuel cells). The prediction of heat and mass transfer, in connection with superimposed flow processes, is of great importance here. This is particularly relevant for the areas of material design, for the determination of heat transfer effects and also for material separation.

CFD for the energy transition

In addition to the above-mentioned research topics, the IDM also deals with the modelling of flow processes in the subsurface (groundwater flow). Here, geological layers are completely dissolved in their composition in order to be able to analyse the anisotropic flow behaviour for the design of remediation processes. Other fields of application are dedicated to energy generation and storage, based on textile solar absorbers (textile spacer fabrics) and water harvesting by textile mist collectors.

Current research projects

- Textile solar thermal energy: A textile-based collector with integrated latent heat storage is used for solar thermal energy utilisation.
- MicroBiome: A 3D modelling of porous anisotropic sand layers, to predict flow behaviour, is used to support an in-situ groundwater remediation process

Other research topics in the application phase deal with:
- the optimisation of protein distribution by porosity design of diagnostic carriers,

- the inductive heating of graded metal foams,
- the adsorption of endoctrine disruptors based on lignin-containing membrane structures for drinking water treatment.

Grain structure developments

Figure 1

Figure 2

Figure 3

Figure 4

Wetting and two-phase drop movement

Simulation of drop formation on a fibre and on a rough surface.

Simulation of the drop development of two non-miscible liquids on a fibre.

Effects of the flow behaviour of fluids

Temperature distribution in a flow-through fissure.

Dendritic phase formation under the influence of flow.

Dendritic phase formation under the influence of flow.

Elastic stresses and strains

Left: Variant distribution
Middle: von Mises tension
Right: Variant distribution and von Mises tension

2D martensite transformation in a polycrystalline, austenitic structure with heterogeneous nucleation.

3D martensite transformation in an austenitic grain. Growth of martensitic variants inside an austenitic grain.

Crack propagation in a polycrystalline material.

Multiscale simulation of the thermomechanical stress in a brake disc.