MACH SAYISININ TURBOJET MOTORU TERMODİNAMİK VERİMLERİ ÜZERİNDEKİ ETKİSİ: BİR UAV UYGULAMASI

Hava araçlarının karmaşık yapılı sistemler olup tasarım süreçleri detaylı analizlere ihtiyaç duyarlar. Sonraki nesil uçaklarda itki sistemlerinin performansı için termodinamiği kurallarını kullanmak gereklidir. Bu sebeple termodinamiğin I. ve II. Kanunlarını, akışa ve momentum dengesine uygulamak gereklidir. Bu çalışmada, küçük bir turbojet motorunun enerji ve ekserji performansı üzerinde uçuş Mach sayısının etkileri, uçuş irtifası 8,000 m alınarak incelenmiştir. 0.3≤ M0≤0.8 aralığında motorun ekserji verimi %48.61-49.88, enerji verimi %3.25-9.96, olarak hesaplanmıştır. Bu ana verimlere ilave olarak, kompresör ekserji verimi %89.45, yanma odası ekserji verimi %61.11, türbin ekserji verimi %89.21 ve egzoz ekserji verimi 84.15 olarak hesap edilmiş olup, uçuş Mach sayının arttıkça ekserji yıkımının da düşük miktarda azaldığı görülmüştür.

Anahtar Kelimeler:

Turbojet, ekserji, enerji, UAV, IHA

MACH NUMBER EFFECT ON THE THERMODYNAMIC EFFICIENCIES OF A TURBOJET ENGINE: AN UAV APPLICATION

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.

Keywords:

Turbojet, exergy, energy, UAV, IHA,

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[1] DİNÇ, A., “Optimization of a Turboprop UAV for Maximum Loiter and Specific Power Using Genetic Algorithm”, International Journal of Turbo&Jet Engine, DOI 10.1515/tjj-2015-0030, 2015.
[2] FAA,Federal Aviation Administration, Aviation Safety Unmanned Aircraft Program Office (UAPO), Interim Operational Approval Guidance. Unmanned Aircraft Systems Operations in the U. S. National Airspace System. 2008.
[3] U.S. Department of Defense. Office of the Secretary of Defense 2007–2032 Unmanned Systems Roadmap, 2007.
[4] ANDREU, L. Performance of a ducted micro-turbojet engine. Master’s thesis, Naval Postgraduate School, Monterey, CA, USA, 1999.
[5] GUHA, A., “Optimization of aero gas turbine engines”, The Aeronautical Journal; pp.345-358, 2001.
[6] GUHA, A., “Performance and optimization of gas turbine engine with real gas effects”, Proceedings Institution of Mechanical Engineers, 215, 507-512, 2001.
[7] TURAN, O, AYDIN, H., “Exergetic and exergo-economic analyses of an aero-derivative gas turbine engine”, Energy, Vol.74, 638-650, 2014.
[8] ATILGAN, R., TURAN, O., ALTUNTAS, O., AYDIN, H., SYNYLO, K., “Environmental impact assessment of a turboprop engine with the aid of exergy”, Energy; 58, 664-671, 2013.
[9] BAKLACIOGLU, T., TURAN, O., AYDIN, H., “Dynamic modeling of exergy efficiency of turboprop engine components using hybrid genetic algorithm-artificial neural networks”, Energy, 86:709-721, 2015.
[10] TURAN, O.,” Effect of reference altitudes for a turbofan engine with the aid of specific-exergy based method”, International Journal of Exergy, 11, 252-270, 2012.
[11] TURAN, O.,” An exergy way to quantify sustainability metrics for a high bypass turbofan engine”, Energy, 86,722-736, 2015.
[12] TURAN, O., “Exergetic effects of some design parameters on the small turbojet engine for unmanned air vehicle applications”, Energy, 46, 51-61,2012.
[13] CUMPTSY, NA., Jet propulsion: A simple guide to the aerodynamic and thermodynamic design and performance of jet engines. Cambridge University Press, Second Edition, 2003.
[14] KERREBROCK, J.L.. Aircraft engines and gas turbines. MIT Press, Second Edition, 1992.
[15] SARAVANAMUTTO, H.I.H., ROGERS, G..FC., COHEN, H., Gas turbine theory. Prentice Hall, 5th Edition, 2001.
[16] Microturbo http://www.safran-power-units.com/ (access date: May, 12,2016)
[17] HALL, D.K., Performance limits of axial turbomachine stages. Master of Science Thesis. MIT, USA, 2011.
[18] EL-SAYED, A. F., Aircraft propulsion and gas turbine engines, CRC Press, 2008.
[19] JOHN, H.D., CAMBEROS, J.A., MOORHOUSE, D.J., “Benefits of exergy-based analysis for aerospace engineering applications part I”, International Journal of Aerospace Engineering, 1-11, 2009.
[20] ARNTZ, A., ATİNAULT, O., “Exergy-based formulation for aircraft aeropropulsive performance assessment: theoretical development”, AIAA Journal, 53 (6); 1627-39, 2015.
[21] HEPBAŞLI, A. A., “Key review on exergetic analysis and assessment of renewable energy resources for a sustainable future”, Renewable and Sustainable Energy Reviews,; 12, 593-661, 2008.
[22] BEJAN, A., TSATSARONIS, G., MORAN, M., Thermal design and optimization. USA,Wiley; 1996.
[23] KOTAS, T.J., The exergy method of thermal power plants. Malabar, FL, Krieger Publishing Company; 1995.
[24] DİNCER, I. Environmental and sustainability aspects of hydrogen and fuel cell systems. International Journal of Energy Resources, 31, 29–55, 2007.