1. Ramjet, Turbojet and Turbofan Summary
MAE 5350: Gas Turbines
Ramjet, Turbojet and Turbofan Summary
Mechanical and Aerospace Engineering Department
Florida Institute of Technology
D. R. Kirk

2. RAMJETS
Cycle analysis employing general form of mass, momentum and energy
Energy (1st Law) balance across burner
Thrust performance depends solely on total temperature rise across burner
Relies completely on “ram” compression of air (slowing down high speed flow)
Ramjet develops no static thrust

3. TURBOJET SUMMARY
Cycle analysis employing general form of mass, momentum and energy
Turbine power = compressor power
How do we tie in fuel flow, fuel energy?
Energy (1st Law) balance across burner

4. TURBOJET TRENDS: IN-CLASS EXAMPLE

5. TURBOJET TRENDS: IN-CLASS EXAMPLE (SEE INLET SLIDES FOR MORE DETAILS)

6. Tt4 = 1600 K, pc = 25, T0 = 220 K

7. Tt4 = 1400 K, T0 = 220 K, M0 = 0.85 and 1.2

8. Tt4 = 1400 K and 1800 K, T0 = 220 K, M0 = 0.85

9. TURBOFAN SUMMARY Two streams: Core and Fan Flow
Turbine power = compressor + fan power
Exhaust streams have same velocity: U6=U8
Maximum power, tc selected
to maximize tf

10. TURBOFAN TRENDS: IN-CLASS EXAMPLE

11. TURBOFAN TRENDS: IN-CLASS EXAMPLE
Improvement over turbojet:
4 – 2.4 → 66% at Mach 1
8 – 3.3 → 142% at Mach 0

12. TURBOFAN TRENDS: IN-CLASS EXAMPLE