ENVIRONMENT AND ENERGY

Using high resolution direct numerical simulations of a flow seeded with particles around a sphere, an international research team aimed at studying the hydrodynamic problem of collisions among particles in the potentially turbulent wake of a sphere. HPC system JUQUEEN of JSC served as computing platform for this challenging simulation project.

Two-phase flows with water droplets greatly affect the thermal-hydraulic behaviour in the containment of a Pressurized Water Reactor (PWR). In order to predict the local thermal-hydraulic behaviour in a real containment in the case of a severe accident, scientists of the University of Stuttgart generated a three-dimensional geometry of a model containment based on a German PWR. 

In order to develop economic, efficient, and reliable wind turbines, the knowledge of the mechanisms that evoke transient aerodynamic loads effecting blades, tower, and the nacelle is essential. Using high performance computing technologies, researchers of the University of Stuttgart used high-fidelity Computational Fluid Dynamics (CFD) methods to accurately predict these unsteady loads. Particular interest was paid on the interaction of wind turbine and atmospheric boundary layer.

Scientists of the University of Duisburg-Essen pushed further the state of the art by simulating large-scale coal and biomass flames in furnaces that have been studied in detail experimentally – the Instituto Superior Técnico and the Brigham Young University furnace. Within this project, the largest large eddy simulation (LES) of coal combustion ever to be computed provided high-resolution scalar profiles within the furnace, which allowed investigating the conditions that coal particles are subjected to in these applications and to compute particle combustion histories. LES is able to provide insights to the phenomena occurring in this type of application that are currently not available through experimental means.

Leveraging the high-performance computing capabilities of the HLRS supercomputing infrastructure, scientists of the Theoretical Materials Physics Group of the Paderborn University managed to trace interface defects in amorphous/crystalline silicon heterojunction solar cells. Visualizing the processes with atomic resolution they were able to characterize the processes that compromise the solar cells' efficiency. The findings will help to optimize the solar cells further and to decrease production costs.

Organic Photovoltaics are a promising thin-film solar cell technology since all the constituting layers can be processed from solution processable materials. In order to improve the efficiency of those solar cells it is necessary to optimize their light trapping ability. Different techniques were evaluated in a research project on SuperMUC of LRZ.

A team of scientists of the Technische Universtität München employed an instantaneous steady-state approximation to present steady-state reactivity data from kinetic Monte Carlo (kMC) simulations in the form of an interpolated data field as boundary conditions for the computational fluid dynamics simulation.Their goal was to test the capability of the code in managing complex computational domains, thus allowing for the first time to extend kMC simulations to geometries and conditions relevant to technological applications. 

The cold combustion in fuel cells is a promising alternative energy technology that does not produce greenhouse gases. One of the main problems of solid oxide fuel cells (SOFC) that reduces the efficiency dramatically is the chromium poisoning. The current collectors in SOFCs are made of stainless steel which contains chromium. By chemical reaction chromium can migrate into the porous cathode and react with its surface. This effect degrades the efficiency and has to be controlled.

Fusion energy is a very attractive option to provide large-scale and CO2-free electricity production for centuries to come. Here, the goal is to mimic the way the sun generates its power under laboratory conditions on earth. To this aim, one confines a plasma (i.e., an ionized gas), consisting of two heavy versions of hydrogen, namely deuterium and tritium, in a doughnut-shaped magnetic cage and heats it to about 100 million degrees. In order for this to work, however, the energy confinement – which is controlled by turbulent transport – must exceed a certain level. 

In order to invest in a sustainable energy mix and avoid CO₂ emissions, new energy sources such as fusion energy need to be developed. Understanding turbulent transport is needed for further optimization of fusion reactors but realistic transport time scale simulations of plasma turbulence are computationally very demanding. The aim of the present project is to increase the understanding of the mechanisms behind the sudden improvement in confinement observed in experiments. 

Concerns about the present global energy situation and the impacts of climate change are the driving forces for optimizing combustion power plants operation towards maximum efficiency, and thus minimizing the emission of greenhouse gases. Computational modelling of the combustion process in industrial scale combustion systems has become a key technology to achieve this ambitious goal.