Given the trend towards leaner combustor primary zones and concurrent increases in injector air mass flow rates for emissions reduction, an automated fuel injector optimisation procedure is proposed for a generic aero-engine combustor. The modelling assumptions and the design of the toolset to be applied for the optimisation study, as well as preliminary results from the computational tools, are presented. The proposed configuration will enable the consideration of the following design parameters: the number of swirlers, the swirl number for each swirler, the air mass flow splits between the swirlers, and the fuel mass flow split for multiple prefilming surfaces. Results from the unsteady RANS spray combustion solver available through the OpenFOAM software package are combined with semi-empirical correlations in order to estimate and capture trends in emissions. Pattern factor and susceptibility to thermoacoustic oscillations are assessed directly through the simulation output. Due to computational costs, only the cruise condition is considered for optimisation, and off-design considerations have been limited to their impact on preliminary combustor sizing and design. A multi-fidelity optimisation strategy incorporating a multi-objective Tabu Search algorithm is also presented in light of the nature of the problem and the complexity of the design spaces constructed from CFD results.
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