GT

Question 1

thermodynamic combustion cycle

Name the 4 part process cycle of the OTTO cycle

Answer 1

• Isentropic compression
• Heat addition
• Isentropic expansion
• Exhaust

Question 2

What is the compression cycle of an engine called?

Answer 2

Brayton cycle it is a continous flow engine

Question 3

Name the 2 types of gas turbines

Answer 3

• Axial (expensive)
• Centrifugal (Cheap)

Question 4

What is the good about the gas turbine?

Answer 4

• Cheap to run
• High power

Question 5

What are the operating considerations of a GT?

Answer 5

• Fuel economy
• Engine hour economy

Question 6

What are the requirements of a compressor?

Answer 6

• Large amount of air
• Efficient
• Stable
• Compact

Question 7

What is the difference between Axial & Centrifugal compressors?

Answer 7

• Centrifugal changes air direction
• Axial smaller
• Centrifugal easier to fix

Question 8

How does an axial compressor work?

Answer 8

Draws air in along a torturous path through rotating blades to increase pressure.

Question 9

Name 3 types of compressor blades

Answer 9

1. Solid root
2. Fir tree root
3. Dovetail Root

Question 10

Name 3 types of seals on the lub oil system

Answer 10

1. Lip
2. Mechanical
3. Labrinth

Question 11

Change unit

In the CU oil system the most common elements for lubrication are?

Answer 11

• Bearings
• Pumps
• Filters
• Coolers
• Tanks

Question 12

Name 3 uses of air bleeds.

Answer 12

1. Cooling
2. Sealing
3. Bearing mist lub

Question 13

What does air bleed do?

Answer 13

Directs air to maintain optimum engine temp

Question 14

Name 2 uses for the High pressure shut off cock (HPSOC)

Answer 14

1. Shut off fuel
2. Recirc fuel

Question 15

Types of combustion chambers

What are the 3 methods of combustion in Gas turbines?

Answer 15

1. Can-annular
2. Annular
3. Radial

Question 16

Name the requirements for a combustion chamber

Answer 16

• Efficient
• Easy ignition
• Clean exhaust
• Stable temp

Question 17

Fuel injector

What is the purpose of the Burner?

Answer 17

Deliver atomised fuel to combustion chamber

Question 18

How is a GT started?

Answer 18

A HV spark igniter

Question 19

Describe High energy ignition unit

Answer 19

Mounted on the module & convert LV DC to HV

Question 20

Describe the Turbine design layout

Answer 20

• LP & HP casings made from titanium
• Nozzle guide vanes direct high temps
• HP turbine drives the HP compressor

Question 21

What do Splitter/silencers do?

Answer 21

• Reduces noise
• Reduces turbulance

Question 22

Name the 4 types of fire supressant used

Under control of MEO1 ,key switch box local to module

Answer 22

1. Halon
2. 1301 BTM
3. CO2
4. Water mist/nitrogen

Question 23

Why are GT cleaned?

Answer 23

• Remove Corrosive deposits
• Extend life

Question 24

Describe 2 types of borescope

Answer 24

• Rigid-Allows access to remote areas in straight line
• Flexible-Use fibre optics