1. Creation of Compact Supersonic Turbojet
P M V Subbarao
Associate Professor
Mechanical Engineering Department
Add More Energy to Lively Jet…

2. Obesity of Supersonic Turbojet Engines
Mac=0
t0,cc=4.5
Mac=0.5
Mac=1.0
Mac=1.5
Mac=2.0
Specific Thrust kN.s/kg
Mac=2.5
Mac=3.0 rp

3. Summary of Turbojet Performance
A high compressor pressure ratio is desirable for subsonic flight for good specific thrust and low fuel consumption.
A special care must be used in selecting the compressor pressure ratio for a supersonic flight.
Rapid drop in specific thrust with pressure ratio at supersonic conditions.
Rapid fall in specific thrust under supersonic conditions is still a serious concern for domestic use.

4. Turbo Jet with Afterburner : Enhanced Energy of Gas
inlet 1 2 5 3 6 4

5. Elevation of Nozzle Inlet Temperature
After Burner : More Energy at Same Life

7. Nozzle with Enhanced Energy of Gas
inlet 1 2 7 5 3 6 4

8. Jet Static Temperature
Jet Total Temperature :
Jet Static Temperature :

9. Enhanced Kinetic energy of AB Jet
Maximum obtainable Mach number of Jet

10. Performance of Turbojet with AB
Specific Thrust S
Thrust Specific Fuel Consumption TSFC
Propulsive Power or Thrust Power:

11. Comparative Study of Jet Performance with AB & w/o AB
rp = 10 & 0,cAB= 0,cc
W AB
W AB
W/O AB
TSFC
Specific Thrust
W/O AB

12. Ideal Afterburning Turbojet Engine Performance : Specific Thrust Vs Compressor Pressure Ratio
AB= cc
2.5
Specific Thrust kN.s/kg
3.0
r0p,comp

13. Improvement in Specific Thrust
Specific Thrust kN.s/kg
r0p,comp
2.5
3.0
AB= cc
M=0.0
0.5
There exist a pressure ratio for each Mach number of a supersonic flight, that gives maximum specific thrust.
1.0
1.5
2.0
Compressor Pressure Ratio : r0p
Specific Thrust kN.s/kg
Maircraft
M=0.0
0.5
1.0
1.5
2.0
2.5
3.0

14. Ideal Afterburning Turbojet Engine Performance : TSFC Vs Compressor Pressure Ratio
Mac
3.0
TSFC kg/ kN.hr
r0p,comp

15. Penalty on TSFC rp
TSFC kg/ kN.hr rp
TSFC kg/ kN.hr
Mac

16. Ideal Afterburning Turbojet Engine Performance : f Vs Compressor Pressure Ratio
r0p,comp

17. Ideal Afterburning Turbojet Engine Performance : Efficiencies Vs Compressor Pressure Ratio

18. Optimal design of A Turbojet ????

19. Simple Turbojet :Optimum Compressor Pressure Ratio
At supersonic flight conditions, a maximum value of Specific thrust is Exhibited at certain compressor pressure ratio.
The value of pressure ratio for maximum the specific thrust at a given flight Mach number can be evaluated by differentiation of specific thrust equation.
For Maximum Specific Thrust:

22. Design Variables for A Compact Turbojet
W AB
r0p,opt
W/o AB
Mac

23. Performance of the Compact Turbojet Engine
With AB
Specific Thrust kN.s/kg
TSFC kg/ kN.hr
W/o AB
Mac