A. August

Modelling of transient heat conduction with diffuse interface methods

We present a survey on different numerical interpolation schemes used for two-phase transient heat conduction problems in the context of interface capturing phase-field methods. Examples are general transport problems in the context of diffuse interface methods with a non-equal heat conductivity in normal and tangential directions to the interface. We extend the tonsorial approach recently published by Nicoli M et al (2011 Phys. Rev. E 84 1-6) to the general three-dimensional (3D) transient evolution equations. Validations for one-dimensional, two-dimensional and 3D transient test cases are provided, and the results are in good agreement with analytical and numerical reference solutions.

Metallic foam structures, dendrites and implementation optimizations for phase-field modeling

We present our current work in the field of computational materials science with the phase-field method on the high performance cluster XC 4000 of the KIT (Karlsruhe Institute of Technology). Our investigations include heat conduction of open cell metal foams, dendritic growth and optimizations of the concurrent processing with the message passing interface (MPI) standard. Large scale simulations are applied to identify relevant parameters of heat conduction and dendrite growth. Our overall goal is to continuously develop our models, numerical solution techniques and software implementations. The basic model and parallelization scheme is described. Disadvantages of 1D domain decomposition compared to 3D domain decomposition for large 3D simulation domains are explained and a detailed analysis of the new 3D decomposition needs to be performed. The data throughput of parallel file IO operations is measured and system specific differences have been found which need further investigations.

Phase-field simulations of large-scale microstructures by integrated parallel algorithms

In this report, we present specific model extensions of the phase-field method [17] implemented in the software framework PACE3D and summarize the underlying parallelized algorithms. Three different applications of microstructure evolution processes are illustrated and the need of large representative volume elements and of efficient parallelization. Within a first application, a parallel connected component labeling algorithm, is optimized for a large number of computing units, and is used for the simulation of pore development in the sintering processes. The second topic discusses a brute force study of the Read-Shockley model, to investigate recrystallization and abnormal grain growth in anisotropic polycrystalline material systems. The third topic is focussed on heat transfer and fluid flow in metallic foam structures depending on the porosity as base material for new heat storage systems.

Heat propagation in computer designed and real metal foam structures

Purpose The purpose of this paper is to demonstrate a method for modeling of cellular structures by means of Voronoi tessellation and to conduct a validation by comparison with real metal foam structures. Design/methodology/approach Heat propagation behavior of open-pore metal foams is studied for both experimental as well as computer-modeled structures showing excellent agreement. The 3D open-pore structure of the real foam is reconstructed from 2D light microscope images in-depth. Findings An algorithm to create synthetic open-pore foam structures has been developed. Originality/value The algorithm for modeling synthetic open-pore cellular structures allows the random distribution of the individual pores close to reality.