Gas Turbine Engine Flashcards

(30 cards)

1
Q

Can an engine start by itself?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Is it safe to cut holes in a turbine blade to improve cooling?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Purpose of shroud at the tip of the turbine blades?

A

Help to minimise tip losses as well as provide a damper to prevent vibrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Annular combustors suffer from?

A

Low rigidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How to prevent engine stall due to choked flow?

A

Extract bleed air from the compressor stage after the stalled section.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Centrifugal Compressors have the following advantages compared to axial compressors? (5)

A
  • Simpler
  • More rugged
  • Cheaper to manufacture
  • Greater design flexibility
  • Less severe stall characteristics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Considerations for the design of Air Inlets include:? (5)

A
  • Noise attenuation
  • Radar attenuation (stealth)
  • Nozzle secondary airflow
  • Dust / Sand Particle Separation
  • Airflow bypass to assist in engine starting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Does an aircraft’s velocity affect the thrust produced by its engines?

A

Yes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the purpose of flame holder?

A

To contains the flame of combustion and prevents flame out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Is ice formation desirable?

A

Undesirable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Air starting of an engine involves the use of? (3)

A

an APU, a GPU or a Cartridge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is required for afterburner?

A

A variable-area exhaust nozzle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Turboshaft engines contains a?

A

Free turbine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

[INFO]

Fnet = (Mass Flow Rate)(Vexit - Vinlet) + Aexit(Pexit - Pin) + …

A

Thus, you can accelerate a large mass through a small increase in velocity or a small mass through a large increase in velocity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Mach number?

A

The ratio of the speed of a body to the speed of sound in the surrounding medium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Brayton Cycle?

A

an idealised cycle with no energy losses to the surroundings. In actual cycles, the amount of energy lost is accounted for through process efficiency.

17
Q

What is the purpose of the exhaust nozzle?

A

To regulate back pressure on the turbine, accelerate exhaust gases to achieve desired jet velocity and deflect/reverse thrust.

18
Q

The exhaust nozzle is “used/not used” to increase backpressure?

19
Q

Cooling methods in the turbine include? (4)

A
  • Convection
  • Impingement
  • Film
  • Transpiration
20
Q

Low Cycle Fatigue

A

failure typically occurs <100,000 cycles and is due to engine start/stop or throttle cycle.

21
Q

High Cycle Fatigue

A

failure typically occurs >100,000 cycles and is normally caused by vibratory stress.

22
Q

The Health & Usage Monitoring System (HUMS) is used for?

A

monitoring the health of the engine, which involves usage monitoring and flight data acquisition. It does not retrieve weather data or monitor air conditioning.

23
Q

Magnetic chip detectors are used for?

A

To catch ferrous particles in the oil system.

24
Q

High viscosity oil is used in turbo-propeller engines due to?

A

high mechanical loads involved.

25
The Variable Divergent/Convergent Nozzle of the F100 engine is designed to?
significantly reduce the actuation forces necessary to reposition the nozzle.
26
In the Axial Compressor, stator or rotor comes first?
stators come before rotors to direct air into the rotor.
27
Air inlet ducts are generally rated by?
Their duct-pressure efficiency ratio and ram recovery point.
28
Common Thermodynamic Processes (3)
- Isobaric - Constantly Pressure - Isochoric - Constant Volume - Isentropic - Constant Entropy & Temperature
29
Thermal Barrier Coating (TBC) is applied to stationary components in the combustion chamber to?
Reduce wall temperatures and gradients by reflecting gas radiation or providing a layer of insulation between hot gases and the wall.
30
The disadvantage of using an airblast atomiser is?
at low air velocities, such as during start-up, the fuel droplets tend to be large, limiting the efficiency of the engine.