1. Unit 2 Aircraft Propulsion
J Singh / MS Deepa
Aeronautical

2. Refresher Mass Transfer Reviewed Working of a Gas Turbine Engine
Thrust Equation for Turbojet, Turbofan, Turboprop, Ramjet Engine
Quiz
Tutorial posted on “aero2016” google group
8th August, All tutorials will be discussed in the class. Pl work out individually

3. Ideal (Brayton Cycle)
Compression and Expansion are Reversible and Adiabatic
Change of KE of working fluid between inlet and outlet of each component is negligible
No pressure losses in the inlet, CC, exhaust ducting, ducting
Working fluid has the same composition throughout the cycle
Perfect gas with constant specific heats
Mass flow of gas is constant throughout the cycle
Heat transfer is complete, so that Temperature rise on cold side equals the temperature drop on hot side

4. Performance of Gas Turbine Cycles
Forward speed and Altitude
Specific Work output and Cycle Efficiency depend only on Pressure Ratio and Max Cycle Temperature

5. Refresher Tutorial posted on “aero2016” google group
8th August, All tutorials will be discussed in the class. Pl work out individually
Question papers (class in-charge)
Brayton Cycle: Efficiency & Specific Work output (depend only on…. and…..)

6. Cycle Analysis
Heat Exchange
Reheat
Intercooled
Numerical (V.Ganesan)

7. Factors affecting Thrust
Velocity
Temperature
Altitude / Pressure
Also refer class notes provided

8. Thrust Propelling Nozzle Outlet: Area (Ae) = 0.2150 m²
Pressure (Pe) = kPa
Pressure (P0) = kPa (ISA)
Mass Flow (W2) = 70 kg/s
Velocity (Vj) = 590 m/s
Calculate Thrust (kN) at Sea Level Static Condition.

9. Thrust with Reheat Afterburner Propelling Nozzle Outlet:
Area (Ae) = m²
Pressure (Pe) = kPa
Pressure (o) = kPa
Mass Flow (W2) = 70 kg/s
Velocity (Vj) = 740 m/s
Calculate Thrust (kN) at Sea Level Static Condition.

10. Thrust Augmentation
There are occasions when maximum thrust from a basic gas turbine engine is inadequate, and some method of increasing the available thrust is required

11. Afterburning / Reheat
This is employed to boost the thrust at various altitudes thus increasing aircraft performance. This is limited to short periods only, such as combat or take-off, due to the increased fuel consumption.

12. Water / Water-Methanol Injection
This is employed to restore, or even boost, the thrust from a gas turbine operating from hot or high altitude airfields. This method is now normally limited to turboprop powered transport aircraft.

13. Aircraft engine schemes (1)
Turboprop with two stage
centrifugal compressor
Twin-spool turboprop with
axial compressor

14. Aircraft engine schemes (2)
Single spool turbojet
with axial compressor
Turboshaft with twin-spool
gas generator
Twin-spool bypass

15. Aircraft engine schemes (3)
Triple spool turbofan
(separate exhausts)
Unducted (aft)fan
or propfan