1. Analysis of Turbofan Engine
P M V Subbarao
Professor
Mechanical Engineering Department
How to decide Cold Vs Hot ???

2. Ideal Turbofan Cycle
Inlet 2 3 7c 7h 4 1 5 6
Total thrust is generated by both cold and hot jets..

3. Analysis of fan Analysis of Fan 2 3
Inlet 2 3
Analysis of fan
Design Parameter : Stagnation pressure ratio

4. Analysis of Compressor
Inlet 4 3
Design Parameter : Stagnation pressure ratio

5. 5
Inlet 4

6. Combined Gas Dynamic & Thermodynamic SSSF model for Turbine6 5
Inlet

8. Vigor of Hot Jet

9. Combined Gas Dynamic & Thermodynamic SSSF model for Hot Nozzle

10. Available life at the inlet to the nozzle will decide the magnitude of T7h.

14. Combined Gas Dynamic & Thermodynamic SSSF model for Cold Nozzle

17. Generation of Thrust : The Capacity
Propulsive Power or Thrust Power:
Specific Thrust based on core flow S
Specific Thrust based on total flow S

18. Thrust Ratio
Ratio of specific thrust of core stream to specific thrust of fan stream.

19. Thrust Specific Fuel Consumption TSFC

20. Aviation Appreciation
Propulsion Efficiency

21. Performance Analysis of Turbofan
Operational Parameters : Flight Mach number & Ambient conditions.
Design Variables : Fan Pressure Ratio, Bypass Ratio, Compressor Pressure Ratio, Combustion Chamber Temperature Ratio.
Fan Effects :
Fan Pressure Ratio
Bypass Ratio.
Fan Stream Thrust Vs Total Thrust.

22. Utility of of Fan Bypass Ratio
TSFC
r0,p,fan= r0,p,comp=15 T0max=1200K Mac =0.75

23. Fan Effects …. : Fan Pressure Ratio: Mac = 0.75
r0,p,comp=15.0
a=4.0
T0max=1200K

24. Effect of Flight Mach Number : Compactness
Specific Thrust kN.s/kg
Mach Number

25. Effect of Flight Mach Number : Fuel Economy
TSFC
Mach Number

26. Effect of Flight Mach Number : Propulsion Efficiency