Large Eddy Simulations of complex multicomponent swirling spray flames in a realistic gas turbine combustor

Large Eddy Simulations of the realistic liquid fueled gas turbine combustor LOTAR operated at ONERA are performed for two fuels; a conventional JetA-1 and an alternative alcohol to jet fuel At-J, each mod-eled by a 3-component formulation. JetA-1 is composed of n-dodecane, methyl-cyclohexane and xylene each corresponding to the major hydrocarbon families found in real fuel. At-J is a synthetic drop in fuel com-posed of only branched chain alkanes, iso-octane, iso-dodecane and iso-hexadecane. Analytically Reduced Chemistry and multicomponent spray evaporation model coupled to the dynamic thickened flame turbu-lent combustion model are employed to understand the processes involved in turbulent spray flames in the LOTAR configuration. The objectives are to predict and understand the potential effects of staged vapori-sation and consumption of the fuel components, and their impact on the spray flame structures. Simulations confirm the role of preferential evaporation in establishing and stabilising the reaction zone. JetA-1 evap-oration zones extend deep into the rich burnt gasses resulting in a combustion regime with the possibility of droplet clusters burning individually. At-J which is more volatile, leads to complete combustion with the majority occurring due to the premixed lean reactions of the smaller pyrolysed components. The need to further include models capable of identifying and handling combustion regimes encountered in such spray flames is hence highlighted. This work is intended as a starting point for improving multicomponent spray modelling and requires additional experimental data for validation. & COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Large Eddy Simulations were conducted to compare the characteristics of traditional JetA-1 fuel and an alternative At-J fuel in the LOTAR combustor. The simulations revealed that JetA-1 fuel forms combustion regime with the possibility of droplet clusters burning individually, while At-J fuel achieves complete combustion through premixed lean reactions. The study highlights the need to develop models capable of identifying and handling combustion regimes encountered in such spray flames.