Numerische Untersuchung der Lärmentstehung und der Lärmabstrahlung turbulenter Flammen

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The objective of the research project is to enhance the physical understanding of noise emission by pre-mixed turbulent combustion. This understanding is mandatory to engineer industrial burners in stationary gas turbines and aircraft engines that are environmentally friendly. The problem is that acoustically induced in-stabilities in the combustion chambers strongly influence optimal operating conditions. In coorperation with the partners of the first project phase (TP1 (Paschereit), TP2 (Janicka), TP4 (Bockhorn)) the generic burner configuration will be piloted such that the burner can be operated in the lean premixed regime. The impact of various parameters, i.e., the momentum, the temperature, the mixture of the unburnt gas, and the turbulence intensities of the nozzle boundary layer, on the acoustic emission of the turbulent flame will be investigated and will be quantified w.r.t. the acoustic field. The experiments conducted by TP1 (Paschereit) will be inves-tigated by large-eddy simulations by TP2 (Janicka) and TP4 (Bockhorn) to compute the resulting acoustic field in the present subproject TP3 (Schröder). Additionally, questions concerning the required numerical solution of the flame front for a correct acoustic simulation will be investigated in collaboration with TP2 (Janicka). Furthermore, a detailed evaluation of a direct numerical simulation by TP4 (Bockhorn) will significantly enhance the insight into the related acoustic source mechanisms using the source formulation from the acoustic perturbation equations.