Global warming potential optimization of a turbofan powered unmanned aerial vehicle during surveillance mission

Abstract

Gas emissions from all sources including air transport contribute to global warming. There are tremendous efforts to decrease the greenhouse gas emissions in all sectors. In this study, for a turbofan engine powered unmanned aerial vehicle, Global Warming Potential (GWP) calculations have been performed covering a range of flight Mach number and altitude. Unmanned aerial vehicles have different mission profiles and usage characteristics than manned aircraft. Therefore their emissions are also different than manned aircraft due to different flight altitude, loitering (surveillance) speed and engine power setting etc. Global warming potential was calculated with a genuine code combining aircraft performance, engine performance and exhaust gas emissions for all flight points during surveillance mission. Exhaust gases of CO2, H2O and NOx were calculated and at each leg of flight as they contribute to GWP. Results were presented to illustrate the GWP magnitudes for different flight speed and altitude in a comparative manner for the turbofan powered UAV. Optimization calculations were done by using genetic algorithm. For an investigated range of 6–16 km flight altitude and 0.25–0.75 flight Mach number, total surveillance mission GWP is lowest around 13 km and 0.37 Mach number as optimum values. However, GWP per hour during constant speed and altitude surveillance (loiter) is minimum around 15 km and 0.43 Mach number for assumed UAV flight mission profile.