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Proposing Institution

TU Darmstadt, Fachgebiet Simulation reaktiver Thermo-Fluid Systeme
Project Manager

Sebastian Popp
Otto-Berndt-Straße 3
64287 Darmstadt
As part of the changing energy landscape, the influence of hydrogen as fuel will further increase.Fuel flexibility of conventional combustion applications is a crucial issue for their development,when using e.g. blends of hydrogen and fossil fuels or even pure hydrogen. It is commonly knownthat conventional combustion applications cannot operate with hydrogen or hydrogen additionwithout adjusting the combustion chamber design, due to different combustion characteristicsand flame stabilization mechanisms. Major differences occur due to an increased diffusivity. Anincreasing amount of hydrogen leads to differential diffusion effects, which alter the transportmechanisms towards the reaction zone. Previous studies, looking at these effects, were mainlyfocused on simple jet flames and concluded that detailed diffusion modeling is crucial even forturbulent combustion modeling.The present study addresses differential diffusion in a more complex jet in cross flow (JICF)configuration, which is applied in systems where rapid mixing is required, e.g. aircraft andstationary gas turbines and recent micro gas turbine applications for hydrogen combustion.Therefore, direct numerical simulations (DNS) of a hydrogen JICF will be analyzed, regardingdifferential diffusion effects in different regimes of the JICF. For a regime analysis, the turbulent/non-turbulent interface (T/NT) will be detected, which separates the flow into turbulent and non-turbulent regions in free shear flows through a sharp vorticity increase across the interface. This evaluation is mainly focused on gaining insights for the improvement of flamelet-based modeling approaches, e.g. a flamelet-progress variable model. In addition to detailed diffusion modeling, a DNS with unity Lewis number assumption allows to quantify the influence of differential diffusion on the overall flame structure and flame stabilization mechanisms.

Impressum, Conny Wendler