1. Basic Design Principles of Turbofan Engine
P M V Subbarao
Professor
Mechanical Engineering Department
An Evolution of Turbojet for Better Characteristics???

2. Energy Flow in Jet Engine
Energy input
Long distance travel demands high flight velocity.
A Single hot Jet was creating huge noise.
Also blackmailing the jet engine !!!
High flight velocity leads to drop in compactness and fuel economy.

3. An Evolved design of Turbojet
Inlet 2 3 cj
7 or hj 4 1 5 6
Total thrust may be Shared by both cold and hot jets..
In Soviet designer Arkhip Lyulka elaborated the design of turbojet and created an evolved turbojet.
Created the world's first turbofan engine, and acquired a patent for this new invention on April 22, 1941.

4. Special Design Variable for an Ideal Turbofan Engine
Inlet 2 1

5. Sizing of Fan
Inlet 2 3 1
Design Parameter : Fan Total Pressure ratio

6. Design Parameter : Compressor total pressure ratio
Sizing of Compressor
Inlet 4 2 3 1
Design Parameter : Compressor total pressure ratio

7. Sizing of Combustor 5
Inlet 4 2 3 1

8. Combined Gas Dynamic & Thermodynamic SSSF model for Turbine5
Inlet 4 2 3 6 1