The projected growth of the air transportation system by a factor of two or more within the next 20 years has the potential to increase emissions of greenhouse gases, such as carbon dioxide (CO₂), nitrogen oxides (NO_X), and water vapor. As a result, aggressive goals have been established to reduce fuel burn in future aircraft, which will, as a result, reduce emissions of CO₂ and NO_X. This research has taken on increased significance due to the recent instability of aviation fuel prices and supplies.

NOX can also be reduced by increasing fuel/air mixing in time and space, minimizing combustion zone residency time, maintaining unburned hydrocarbon and particulate burnout, and reducing or eliminating combustor liner cooling. This strategy will be accomplished through development of alternative combustor concepts (like flameless catalytic), advanced fuel/air mixers, high-temperature (ceramic matrix composite) combustor liners, alternate fuels, and active combustor control. The development of advanced low-NO_X combustor concepts is facilitated by high-fidelity, CFD-based computational tools incorporating integrated multiphase and combustion modeling for large eddy simulation in realistic gas turbine combustors.