1. Analysis & Selection of Design Space for Turbofan
P M V Subbarao
Professor
Mechanical Engineering Department
Make the Jet Pair Made for Each Other???

2. Ideal Turbofan Cycle
Inlet 2 3 cj
7 or hj 4 1 5 6

3. Theory of Turbofan Propulsion : Just Enough Work
The power inputs to the compressor & fan = The power output of the turbine

4. Life Infusion Vs Life Loss

5. Capacity of Hot Nozzle Isentropic Hot Nozzle:
Available life at the inlet to the nozzle will decide the magnitude of T7h & M7h
However the strength of hotjet is limited. Also Jet static temperature is low.

6. Velocity of Hot Jet

7. Capacity of Cold Nozzle
Isentropic Cold Nozzle
Inlet cj 3

8. Velocity of Cold Jet

9. Velocity of Jets : Relative Strengths

10. Generation of Thrust : The Capacity
Specific Thrust based on total flow
Specific Thrust based on core flow

11. Relative Contributions of Cold and Hot Jets : Thrust Ratio
Ratio of specific thrust per unit mass flow of core stream to specific thrust per unit mass flow of fan stream.

12. Thrust Specific Fuel Consumption TSFC

13. 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.

14. Compactness : Turbojet Vs Turbofan
For same level of life & Energy of jet
Turbojet
Turbofan

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

16. Influence of Fan: Pressure Ratio: Mac = 0.75
r0,p,comp=15.0
a=4.0
T0max=1200K