M15.5 Flashcards
What is the function of the combustion chamber?
To produce a hot stream of gas for the turbines and jet nozzle
What are the main two components of a combustion chamber?
The casing and the flame tube
What are the two primary conditions necessary for correct and safe combustion?
The correct ratio of fuel and air mixture and the correct air velocity
What is the ratio for a kerosene-air mixture?
15:1
What percentage of airflow is used in the primary combustion?
20%-30%
Where does the flame stabilise in the combustion chamber?
The primary combustion
What is the percentage split of the primary and secondary airflow in the combustion chamber?
20-30% in the primary and 70-80% in the secondary
What is the secondary airflow used for?
For cooling the combustion chamber inner wall via the dilution zone air holes
What are the three types of combustion chambers on gas turbine engines?
- can-type
- can-annualar
- annualar
Why is there interconnection tubes on a multiple-can type combustion chambers?
Because only two combustion chambers have igniter plugs and they help equalise pressure between cans
Why is the can-annular combustion chamber better than the multiple can-type combustion chamber?
Because its smaller, lighter, and stronger
What is the name for the special small gas turbine engine annular combustion chamber?
The reverse flow combustion chamber (airflow direction in the flame tube)
On an annular combustion chamber where are the fuel nozzles and igniter plugs located?
The outer wall of the combustion case
What is the rear flange of the inner wall used for?
To attach the nozzle guide vanes to the high pressure turbine and to support the flame tube
What is the front of the inner wall flange for?
It is the seal surface of the compressor discharge pressure seal
What are the last stator vanes of the high pressure compressor often known as?
Exit guide vanes
Why is there openings on the outer wall of the combustion chamber?
For bleed air from the last compressor stage is fed to the aircrafts pneumatic system
Where are the igniter bosses located?
Slightly behind the row of fuel nozzles
What is the dome section used for?
To connect the inner linner with the outer liner and houses the swirl vanes
What is the secondary airflow cooling system in the combustion chamber known as?
Film cooling
What are the two ways of cooling of a combustion chamber?
Film cooling and using a thin coating of ceramic
