LES based evaluation of multi-component fuel evaporation effects at aero-engine conditions

A new multi-component evaporation model was developed as a part of a study to accurately simulate realistic alternative aviation fuels that may have widely varying fuel physical properties. While the new model is based on the fuel Distillation Curve (DC) it is characterized by notable differences from conventional DC models in the literature. These differences as well as similarities of the current model with the conventional models are described to highlight the strengths and limitations of each of these models. Partial validation of the new model is demonstrated by performing single droplet evaporation tests similar to those available in the literature and the results were compared with the conventional DC model. The impact of pressure on evaporation was demonstrated by simulating single droplet evaporation at different pressures and highlighting the two competing mechanisms, namely heat of vaporization effect and multi-component fuel volatility effects. The newly developed DC model was applied to simulate swirl-stabilized combustor experiments where two alternative jet fuels were employed to study the impact of fuel properties on lean-blow-out. Simulations of stable operating conditions were performed using a low-Mach number LES using flamelet-progress variable approach. These simulations demonstrated that the current models can qualitatively capture the fuel sensitivity on flame stabilization. Further refinement of the LES models (in terms of boundary conditions and computational domain) are required to obtain quantitatively accurate predictions of the flow-fields. This will be the subject of future work.