Assessment of thermodynamic performance and CO2 emission reduction for a supersonic precooled turbine engine cycle fueled with a new green fuel of ammonia

Precooling technology is an effective way to improve flight speed for supersonic precooled engine. To solve the problem of excessive aircraft volume caused by low density of traditional liquid hydrogen, as well as the problems of excessive carbon emission and insufficient heat sink of traditional hydrocarbon fuel, a new precooling fuel is proposed in this paper, i.e., ammonia, which is fully cracked in the precooling process to increase the heat absorption capacity. To evaluate engine performances, three models are developed. The results indicate that the ammonia has a higher heat sink than other fuels in the same volume, and considering the capacity of carrying heat energy, the dual-fuel precooling scheme with ammonia and n-decane will process the best engine performance. Further, the optimal fuel ratio and optimal pressure ratio are 2.78 and 12.49 respectively for the multi-objective optimization between engine performance and carbon emission. Moreover, the maximum flight Mach number of chemical precooled engine could reach 4.51, which is 5.51 times faster than the speed of traditional turbine engine GE90. Furthermore, the carbon emission of chemical precooled engine is 64.29% lower than that of traditional turbine engine GE90 equipped in Boeing 777. •A new green fuel that is ammonia is proposed to be used in the precooled engine.•The dual-fuel precooling scheme with NH3 and C10H22 has better performance.•Multi-objective optimization of engine performance and CO2 emission is finished.•The maximum flight Mach number of chemical precooled engine could reach 4.51.•CO2 is 64.29% lower than that of traditional engine GE90 equipped in Boeing 777.