Effect of Bleed Air on Turbojet Performance

The air drawn from the compressor section to be used in different systems and places in turbojet engines of airplanes is called “bleed air”. In this study, the effect of the bleed air on the engine performance was examined. While the effect of bleed air on engine performance was examined, both the compressor splitting method and the method based on the assumption that all air is removed from the end of the compressor was compared with each other. Additionally, an analytical calculation-based interface was designed. It was aimed that the user could get results quickly and easily carry out the evaluation from the graphs. If it is required, the user can also do component level examination instead of graphical examination. Using the interface created in the MATLAB environment, the relationship of the bleed air with the engine's performance, jet outlet pressure, and specific fuel consumption is presented to the user as graphical and component-level information on the Mach number, altitude, and compressor compression ratio determined by the user. If the results from both methods were compared with the literature, it was determined that the maximum error rate was approximately 1.1%. It has been observed that as the amount of bleed air removed from the compressor increases, the engine's performance and the outlet pressure decrease, while the specific fuel consumption increases.