P Gas Turbine Principles Flashcards
What is the equation for thrust?
Thrust = Mass x Velocity
What is the equation for total thrust?
Total = Fan + Core
What is the Brayton cycle?
- Intake
- Compression
- Combustion
- Exhaust
What are the names of the 5 engine modules?
- Intake
- Compressor
- Combustor
- Turbine
- Exhaust
What is the relationship between thrust and TAS?
As TAS increases:
- Thrust lost due to momentum drag increases
- Thrust gained from ram effect increases
Overall thrust is fairly constant with TAS
Which 3 factors effect thrust?
- Altitude
- Speed
- Ambient temperature
What ambient conditions provide the worst thrust?
Hot and humid due to less dense air
What happens above M0.4?
Engine benefits from ram effect increasing thrust
How does engine bleed effect thrust?
Reduces - takes mass flow from just before the combustor and reduces thrust
How does intake heating reduce thrust?
Reduces the air density and therefore the mass flow of air
Where is maximum thrust produced?
On the ground
What is thermal efficiency?
Describes the efficiency with which fuel is converted into kinetic energy - determined by combustion temperature and pressure ratio
Reassure ratio calculated?
The difference in pressure between input pressure (P1) and compressor outlet pressure (P3)
What is propulsive efficiency?
Efficiency with which kinetic energy is translated into propulsive force
How does a FADEC determine thrust?
- Compares intake pressure an exhaust outlet pressure
Or - Uses N1, which is the speed of the fan displayed as a percentage
