Effects of using hydrogen on the exergetic and environmental damage performance of an UAV turbojet engine

Abstract

In this study, the performance effects of using hydrogen instead of JP-8 fuel in an unmanned aerial vehicle (UAV) jet engine was investigated. Exergy analysis and environmental damage analysis were used to obtain performance parameters. These performance parameters were exergy destruction ratio, thrust-specific fuel consumption, air-to-fuel ratio, exergy efficiency, waste exergy ratio, environmental effect factor, sustainability index, and exergetic improvement potential values. Turbojet engine was operated at three different throttle settings (50%, 75%, and 100%) to examine the impact of different load types on the performance parameters. The results obtained by using JP-8 and hydrogen fuels at different throttle settings showed consistency. For all throttle settings, the highest exergy efficiencies took place in the nozzle as approximately 90%. On the other hand, the combustion chamber had the lowest exergy efficiencies for all conditions and took values between 30% and 40%. Calculated exergy destruction ratios indicated that the hydrogen use improved or saved the jet engine's energy performance. Except the combustion chamber, compressor, turbine, and nozzle exergy destruction ratios decreased as 6.2%, 6.5%, and 10.8%, respectively. Moreover, the use of hydrogen fuel did not significantly change the performance parameters, in fact reduced the environmental impact approximately 113%. The findings indicated the potential benefits of hydrogen fuel use when compared to JP-8 fuel.