15.5 Combustion Section Flashcards
(31 cards)
What is the function of the combustion section of the engine?
It raises the temperature of the air passing through the engine
Is fuel and air still supplied to the combustion chamber when ignition is turned off?
Yes
What zone does the flame stabilise in?
Primary zone
How is the fuel/air mixture electrically ignited?
Igniter plug
What are the 2 main components of a combustion chamber?
Combustion chamber casing and flame tube
What does a flame tube do?
Guides and controls flame
What does the combustion chamber casing do?
Takes air pressure loads and protects engine parts from hot gases
What are the 3 types of combustion chambers?
Can, can annular and annular
What type of combustion chamber is most common on GTEs?
Annular
What type of combustion chamber is most common on old GTEs with centrifugal compressors?
Can type
How many flame tubes does an annular type combustion chamber have? Is it fixed or moveable?
- Fixed at aft end and moveable at the other end.
What happens if there is excessive fuel or the temperature is too low in the combustion chamber?
Carbon monoxide buildup
Why is a dual (shorter) combustion chamber used?
Decreases the time exhaust gases are in the hot area to decrease nitrogen oxide
Where does primary air enter for flame tube cooling? Located where?
Through swirl vanes located in the dome of the flame tube.
Where does secondary air enter for flame tube cooling?
Through radial holes in liners
What is film cooling?
Secondary airflow forms a cooling film on inner surface of flame tube liner
What is transpiration cooling?
Same as film cooling but inner surface of flame tube liners have detachable tiles so less air is required
Where are reverse flow annular combustion chambers used?
Used on small GTEs and APUs
How does a reverse flow annular combustion chamber function?
Flame tube airflow goes in different direction to overall airflow
What are the 3 sections of an annular combustion chamber?
Combustion case, flame tube and external components
Is the combustion chamber casing part of the load carrying engine structure in an annular combustion chamber?
Yes
What are the 3 parts of a combustion case in an annular combustion chamber?
Outer wall, inner wall and diffuser
What 3 things does the outer wall have on an annular combustion case?
Has openings, Nozzle pads and ignition bosses.
Why does the outer wall of an annular combustion case have openings?
To feed bleed air from last compressor stage tvthe aircraft’s pneumatic system
