Energy and exergy-based thermodynamic analysis of the scimitar engine at mach 5.0

Almost all published studies about the Scimitar engine are performed by CFD analysis or thermodynamics simulators. This study started after realizing the need for studies regarding the thermodynamic model in detail for the Scimitar engine. Scimitar engine has features of three different propulsion engines in combination to reach the Mach 5.0 cruise speed. Turbofan mode is in operation between Mach 0.0 and 2.5, ramjet and air-turborocket modes are active between Mach 2.5 and 5.0, and air-turborocket mode is active at Mach 5.0. The purpose of this thesis is to develop a thermodynamic analysis model in detail and to perform an energy and exergy-based thermodynamic analysis of the Scimitar engine at Mach 5.0. Air is considered as an ideal gas mixture of O2 and N2. The importance of chemical composition reveals itself in the convergent–divergent nozzle and combustion chamber. Treating combustion products as air results with a difference (around 400 K) in the temperature of combustion products at the exit of the combustion chamber. Thermodynamic relations regarding the engine components on the air, helium and hydrogen cycles and the rate of global energy and exergy balance have been derived in detail. Additionally, some performance parameters, such as uninstalled thrust, specific thrust, thrust specific fuel consumption, propulsive efficiency, thermal efficiency, overall efficiency, exergetic efficiency, total exergy destruction rate, coefficient of ecological performance, exergetic sustainability index and exergy destruction factor are derived. Finally, calculations for all of them have been performed and the results are compared with the results in the literature.