Large-Eddy Simulation of a Model Aero-Engine Sooting Flame With a Multiphysics Approach

In this work, an in-house developed multiphysics unsteady approach (U-THERM3D) is employed to compute wall temperatures in a loosely coupled manner for a model aero-engine combustor, fueled with a non-premixed ethylene/air mixture and representative of the RQL technology. Large-Eddy Simulation (LES) is carried out to prove that scale-resolving approaches are required for a reliable prediction of turbulent mixing with respect to steady-state methods. A Flamelet Generated Manifold approach is adopted to describe the reactive flow, whereas two additional transport equations are included to predict the soot concentration. For a thorough investigation of the considered aero-engine combustor, cold flow results are firstly presented, highlighting the importance of an accurate predictions of general flow features. Then, the aerothermal fields are analysed to show the overall accuracy of the developed approach and so the impact of heat losses, comparing the results of an adiabatic simulation with respect to the loosely coupled conjugate heat transfer calculation. Finally, the investigation is focused on the prediction of the wall temperature distribution to prove the advantages of the U-THERM3D procedure with respect to steady-state approach.