The increasing environmental requirements in the air transport sector pose great challenges to the aviation industry and are key drivers for innovation. Besides various approaches for increasing the efficiency of conventional gas turbine engines, electric propulsion systems have moved into the focus of aviation research. The first electric concepts are already in service in general aviation. This study analyses the potentials of electric and turbo hybrid propulsion systems for commercial aviation. Its purpose is to compare various architectures of electrical powertrains with a conventional turboprop on a regional aircraft, similar to the ATR 72, on engine and flight mission levels. The considered architectures include a turbo-electric (power controlled and direct driven), hybrid-electric (serial and parallel) and a pure electric concept. Their system weights are determined using today’s technology assumptions. With the help of performance models and flight mission calculations the impact on fuel consumption, CO ${}_{2}$ emissions and aircraft performance is evaluated.

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The research project SynErgie aims to adapt large scale industrial processes to a volatile supply of renewable energy which is expected for the future. The aluminum electrolysis process is one of the biggest consumers of electric energy in Germany. The aim is to vary its nominal process power by ± 25%. This numerical study focuses on the magnetohydrodynamic (MHD) behavior of the electrolysis cells of Trimet Aluminum SE in Essen. To capture the MHD driven flow and electrodynamics inside the electrolysis cells a computational fluid dynamics (CFD) model is developed in the OpenFOAM® framework. This accounts for the influence of neighboring electrolysis cells, the magnetization of ferromagnetic materials, a static ledge profile and the dynamic changes of anode shape caused by the carbon consumption. The simulation predictions show the heave of the aluminum cryolite interface for different line currents. To analyze the behavior of flexible process operation, shifts of the line currents are studied in detail. After shifting the line current, the interface heave changes directly whereas the shape of the anode bottom reacts with a delay in time. This leads to a locally uneven anode cathode distance (ACD) followed by a disturbed current distribution inside the electrolysis cell after shifting the line current. The anodic current distribution is quantified by the model, which can help process operators to identify whether increased anode currents are caused by the line current shift or potential abnormalities like spikes. Graphical Abstract

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