Abstract:

Air vehicles have evolved into extremely complex systems that need detail analysis and tools for an efficient design process. A theoretical formulation based on law of thermodynamics is proposed for assessing the propulsive performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow analysis involving the first and second laws of thermodynamics. To meet this need, this study presents and evaluates flight Mach number (M0) effects on energetic and exergetic performance of a small turbojet engine. Energy and exergy analysis are applied to a small turbojet engine to examine the effects of using different aircraft velocities at constant reference environment (flying altitude is assumed to be constant at 8,000 m). The results of analysis using 0.3≤ M0≤0.8 are the exergetic and energetic efficiency ranging from 48.61% to 49.88% and 3.25% to 9.96%, respectively. Furthermore, exergy efficiency values were found to be 89.45% for the centrifugal compressor, 61.11 % for the combustion chamber and 89.21% for the turbine, and 84.15% for the exhaust, while engine exergy destruction is also slight decrease with flight Mach number.

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