The design of a modern aero-engine combustor is strongly driven by severe emission regulations. The paper describes an automated preliminary aero-thermal design process for a rich-burn combustor by combining different low fidelity analysis tools in order to speed up the preliminary design loop and provide improved combustor designs. Design evaluation is performed by a knowledge-based preliminary design tool coupled with a network solver. The preliminary design tool provides a 2D geometry model and cooling layout based on industrial in-house design rules. The 1D network solver then calculates the air distribution inside the combustor for two state-of-the-art combustor cooling schemes, i.e., single skin cooling and double skin tiled cooling. The computed air distribution is subsequently used to predict emissions which are minimized by using a genetic multi-objective optimization algorithm. As a result, better designs are obtained with the prescribed approach compared to a human reference design. Nomenclature, c i,j = flow/geometry specific constants λ = node mass source afr 1 = air-fuel-ratio of injector ρ = fluid density afr 2 = air-fuel-ratio at primary zone exit Indices c = port style • cc = combustor chamber cb = circumferential blockage factor • i,o = inner/inlet, outer/outlet f r = radial factor • m = middle d = diameter • p = port h, h = height, constraint vector • pp,sp = primary/secondary ports l = length • pz,sz = primary/secondary zones = mass flow • 3 = compressor exit n = number • 4 = turbine entry p = pressure • TO = take-off conditions p = parameter vector Abbreviations r = radius CFD = computationalsfluid dynamics s i,j = flow direction at node i,j NO x = nitrogen oxides v = velocity NSGA-II = non-dominated sorting V = volume genetic algorithm-II α = combustor cant angle SN = smoke number

The design of a modern aero-engine combustor is a highly complex and multi-disciplinary task. The combustor design is strongly driven by severe emission regulations and ACARE 2020/2050 goals. Furthermore, new designs have to be developed within short turn-around times. This paper describes a novel approach of an automated preliminary aero-thermal design process of a rich-burn combustor combining 1D, 2D and 3D design tools in order to speed up the design loop and provide improved combustor designs in an early design stage. The automated design process includes a knowledge-based preliminary design tool, an 1D network solver, a parametric 3D geometry model, a meshing tool, and 3D-CFD analysis. At first, a preliminary combustor design is created based on industrial in-house design rules. The preliminary design tool provides a 2D geometry model and cooling layout. It is coupled with an 1D network solver to calculate the air distribution inside the combustor. The design process includes two state-of-the-art combustor cooling schemes, effusion cooling and impingement effusion cooling. An air flow model for both cooling schemes is created within the network, respectively. The computed air distribution is subsequently used to generate boundary conditions for a 3D-CFD analysis. To perform the CFD calculations, a parametric 3D geometry model of a combustor sector has been developed based on a 2D preliminary design which takes into account mixing port properties, fuel injector, and combustor wall cooling. After an automated meshing 3D-CFD computations are performed. As a result, quick automatic estimation of combustor emissions, size and efficiency can be obtained within the design process. A CFD parameter study of a mixing port variation and their effect on the emissions of NOx and soot is performed using the described layout process.