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Toward Innovative Methods for Combustion Prediction in Aero-Engines

Final Report Summary - TIMECOP-AE (Toward Innovative Methods for Combustion Prediction in Aero-Engines)

The aim of the TIMECOP-AE project was to provide the necessary combustion prediction methods that enable the development of practical advanced combustion systems for future engines that will reduce emission levels and fuel consumption. Predictive tools are required to be able to reduce nitrogen oxides (NOx) emissions, to decrease the development time and costs of new combustion systems and to improve the operability of lean-burn combustion systems. All promising approaches to satisfy future emission levels regulations are based on lean combustion technology. However, lean combustion compromises combustor operability, including ignition, altitude re-light, pull-away, weak extinction performance and thermo-acoustic instability behaviour. It is of prime importance to evaluate this transient behaviour in the design stage to ensure good operability. Without these tools the development of these advanced combustion systems will depend on many rig tests. These are costly and time consuming and will reduce our competitiveness.

During the last five years big advances have been made in the field of reactive Large eddy simulation (LES) with gaseous fuels. This approach gives promising results with respect to turbulence modelling and can be used to model unsteady processes. Within the framework of TIMECOP-AE, the LES tools have gained the capability for modelling the combustion process within conventional and low emission combustors over a wide range of operating conditions on liquid fuels. The operating conditions include mentioned transient phenomena. To be able to model these phenomena improvements are required in the models of turbulence, chemistry, turbulence-chemistry interactions, and liquid spray models. The methods and models have been evaluated against high quality validation data which have been obtained by several validation experiments. Some are designed to validate specific models, one is a generic combustor, representative of an aero-engine combustor, and permits to assess the full range of models.