15.5

Question 1

What’s coated on the inner surface of flame tube to protect against heat

Answer 1

Ceramic

Question 2

What airflows used for cooling

Answer 2

Secondary

Question 3

What are MANUFACTURED ways of flame tube cooling

Answer 3

Cooking rings
Corrugated strips
Splash cooling strips

Question 4

How does primary and secondary airflow enter the flame tube

Answer 4

Primary- through swirl vane
Secondary- through liners

Question 5

What is “film cooling”

Answer 5

When secondary airflow forms a cooling film in inner surface of liners which helps to protect liners from Intense heat

Question 6

How’s the dome centred within the combustion chamber

Answer 6

Using mounting pins

Question 7

How many pieces is the flame tube constructed of

Answer 7

2

Question 8

How’s the flame tide held in place

Answer 8

Using inner ans outer liner support

Question 9

What can the holes for feul nozzles and Igniter plugs be used for

Answer 9

Boroscope inspection of flame tube

Question 10

How many igniter plugs are installed in the combuster case

Answer 10

2

Question 11

What’s the purpose of the openings in the outer wall of the combustion case assembly

Answer 11

Bleed air is fed through them to the ac pneumatic system

Question 12

What’s the combustion case made up of

Answer 12

Outer wall
Inner wall
Diffuser

Question 13

What’s the function of the flame tube

Answer 13

Stabilises, controls and guides the flame during combustion

Question 14

What are some advantages and disadvantages of annular combustion chambers

Answer 14

Advantages

Small and light
Efficient
Complete and smokeless combustion
Good thermal load distribution

Disadvantage

Expensive
Removal is difficult and time consuming

Question 15

What’s the most common type of combustion chambers used on modern GTE

Answer 15

Annular combustion chambers

Question 16

What’s an advantage and disadvantage or can annular combustion chambers

Answer 16

Advantages

Small and light
Doesn’t require complicated air ducts
Good structural strength

Disadvantages

High aerodynamic losses
Ignition from one flame tube to others are difficult

Question 17

What are advantages and disadvantages of can type combustion chambers

Answer 17

Advantages

Simple on design
Good strength
Can be removed individually

Disadvantage

Heavy and require a lot of space
Complicated air supply ducts

Question 18

How are Can type combustion chambers joined together

Answer 18

Inter-connecter tubes

Question 19

What does the temperature in the centre of the flame tube reach

Answer 19

Approx 2000 degrees c

Question 20

What two types of airflow go through combusters and what are they used for

Answer 20

Primary and secondary

Primary- combustion
Secondary- cooling

Question 21

What are requirements for safe and efficient combuster operation

Answer 21

Must permit safe ignition of fuel air mixture and stable operation at all times

Question 22

What % of airflow coming from the compressor is primary airflow

Answer 22

20-30%

Question 23

What ratio of fuel to air is required for kerosene fuel

Answer 23

15:1

Question 24

What are the two primary conditions for safe and correct combustion

Answer 24

Correct fuel to air ratio

Air velocity slow enough to ensure combustion is completed in chamber

Question 25

How does the combustion chamber work

Answer 25

Fuel nozzles spray fuel into the combustion chamber

Fuel vaporises and mixes with air

Fuel air mixture ignited by an igniter plug

Question 26

What two main components make up a combustion chamber

Answer 26

Flame tube and combustion chamber casing

Question 27

What’s the role of the combustion chamber casing

Answer 27

Takes air pressure loads and protects the internal and external engine parts from hot gasses

Question 28

What requirements/characteristics should a combustion chamber have

Answer 28

Small and light

Cooling system for materials that come into contact with hot gas flow

High operating lifetime as they’re difficult to replace