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Proposing Institution

Institut für Thermodynamik, Fakultät für Luft- und Raumfahrttechnik, Universität der Bundeswehr
Project Manager

Prof. Dr. Michael Pfitzner
Werner-Heisenberg-Weg 39
85577 Neubiberg
Numerical simulations in the context of Large Eddy Simulation (LES) of turbulent combustion processes is challenging and computationally very expensive if the reaction source term has to be evaluated directly (finite-rate chemistry). Moreover, in LES the sub-grid turbulence-chemistry interaction has to be accounted for. Based on the phenomenological difference between purely premixed and non-premixed (diffusion) flames different models have been developed to circumvent a direct evaluation of the reaction rates. These models lead to good results when applied to the specific type of flame they have been developed for. However, technical burners and combustion devices exhibit partially premixed flames, where fuel and oxidizer is neither perfectly mixed like in the premixed case, nor completely separated like in the diffusion flame. In such a configuration premixed and non-premixed flame structures are locally predominant and evolve over time, hence, none of the phenomenological models lead to good results. In this case finite-rate chemistry provides a way to simulate combustion in partially premixed flames at the expenses of higher computation times. In order to account for unresolved scalar fluctuations on the sub-grid scale in the LES context the reaction source term requires closure. This closure is achieved via a stochastic system, the Eulerian Stochastic Fields (ESF), which form a discrete probability density function of the sub-grid scalar distribution. In this research project the applicability of the ESF method to partially premixed and premixed combustion will be investigated extensively.

Impressum, Conny Wendler