Thermodynamics of Air-Breathing Engines

1. Define propulsion efficiency. 2. Define thermal efficiency. 3. Define engine overall efficiency. 4. Define propeller efficiency. 5. Define thrust specific fuel consumption (TSFC). 6. Define brake specific fuel consumption (BSFC). 7. What is the Brayton cycle and which are the two parameters that define it? 8. What is the expression of the thrust of a turbojet? 9. How does the thrust and the thrust specific fuel consumption of a turbojet engine vary with altitude? Justify your answer. Hint: consider that inlet diffuser efficiency, compressor efficiency, turbine efficiency do not vary with altitude. 10. Explain why T SF C turbojet > T SF C turbof an. 11. Draw the real cycle of a turbofan and explain the processes that take place in the engine. 12. Define bypass ratio (BPR). Which value of the BPR is better: 1 or 5? Justify your answer. 13. Which thrust value of a turbofan engine is larger: takeoff thrust or thrust at cruise velocity? Justify your answer. 14. What are the means of generating thrust with a turboprop engine? 15. Why is the use of the turboprop engines limited to airplanes flying at M=0.5 or less? 16. Define static equivalent shaft horsepower (ESHP). Explain why it is necessary to use ESHP? 17. What is the type of the jet engine shown in the figure? Mark on the figure the name and location of as many components as possible. Briefly describe the role of each component. 18. An engineer who works in your jet-engine design team produced this real-cycle h-s diagram. How many mistakes can you find in the diagram? Explain them.