EXERGETIC ANALYSIS OF AN AIRCRAFT TURBOJET ENGINE WITH AN AFTERBURNER by

An exergy analysis is reported of a J85-GE-21 turbojet engine and its components for two altitudes: sea level and 11,000 meters. The turbojet engine with after-burning operates on the Brayton cycle and includes six main parts: diffuser, com-pressor, combustion chamber, turbine, afterburner, and nozzle. Aircraft data are utilized in the analysis with simulation data. The highest component exergy effi-ciency at sea level is observed to be for the compressor, at 96.7%, followed by the nozzle and turbine with exergy efficiencies of 93.7 and 92.3%, respectively. At both considered heights, reducing of engine intake air speed leads to a reduction in the exergy efficiencies of all engine components and overall engine. The exergy effi-ciency of the turbojet engine is found to decrease by 0.45 % for every 1 °C increase in inlet air temperature