15.05 Flashcards
What is the function of the combustion chamber
To produce a hot stream of gas for turbines and jet nozzle
What two main components does a combustion chamber have
Casing and flame tube (inside casing)
What does a flame tube do
Controls and guides the flame
What two conditions will you need to have a good combustion
Ratio of air:fuel is correct
Air velocity is slow so that that combustion is completed inside the chamber
What is the ratio for complete combustion of a kerosene-air mixture
15:1
Air:fuel
What are the two types of airflow in combustion
Primary airflow
Secondary airflow
Where is the primary airflow used and what percentage of the airflow comes from the compressor
For the combustion process and approximately 20-30%
What temperature do we get at the centre of the flame
2000 degrees C
The secondary air is mainly used for what
Cooling
What are the three types of combustion chambers
- Can-type
- Can-annular
- Annular
Can-type chambers can have what type of chambers
Single chambers and multi-can chambers
What is an advantage of a can-type combustion chamber
Simple design, very good structural strength and can be removed and replaced individually
What is the disadvantage of can-type combustion chamber
Heavy and need a lot of space. Also need complex air supply ducts
What is the disadvantage of can annular combustion chamber
Aerodynamic losses are quite high and the ignition from one flame tube to the other is difficult
What is the most common used combustion chamber
Annular type
What are the chamber casing called in maintenance documentation
Diffuser case or the compressor rear frame
What are the three major parts in flame tube of annular combustion
The dome
Inner liner
Outer liner
What does the combustion case do
Carries the structural load between the compressor case and the turbine case
What does a flame tube do
Stablilzes the flame during combustion
What are the external components of a combustion chamber
Fuel nozzle and igniter plugs
What three things does a combustion case have
Outer wall
Inner wall
Diffuser
What else is located on the outer walls of a combustion case
Fuel nozzle pads and igniter bosses
What are the main components of the flame tube
Outer inner liner
Outer inner cowl
Dome
What does the dome in a flame tube do
Connects the inner liner with the outer liner
The primary airflow enters the flame tube through what
Swirl vanes
What is the cooling method known as in flame tube cooling
Film cooling
What is the more sophisticated method of film cooling
Transpiration cooling requires less air for cooling
What are liner segments
Detachable titles
What is one method used to protect the ,arterial from heat
Thin coating of ceramic material on the inner surface
