15.5 Combustion Chamber Flashcards
What is the key function of the combustion chamber?
-Provides the energy needed to power the turbine
-safe ignition
-stable combustion
-complete combustion
-equal temperature distribution at combustion outlet
-minimise pressure loss
What must the combustion chamber be?
-small and light
-dependable cooling system
-high operating lifetime
How much air travels to primary and secondary airflow?
Primary - 20/30%
Secondary - 70/80%
What is the optimum air fuel mix?
15:1
What is the flame tube?
It control and guides the flame
What is the combustion chambers function?
-takes air pressure loads
-fuel vaporising
-supports the flame tube
What are the basics of combustion?
Fuel air mixture injected
Fuel is vaporised
It is electrically ignited to start the engine
What is the purpose of the primary and secondary airflow?
Primary is combustion
Secondary mixes with hot gas in the dilution zone
What are the uses for can type and disadvantages?
-APU
-centrifugal compressor
They are heavy requiring a lot of space and have complicated ducting
What is the structure of can annular and its design?
-Set of flame tubes placed around the combuster section
-Common outer and inner casing
-High aerodynamic loss
-ignition from one flame tube to another is very difficult
Annular combustion chamber design and structure?
-inner and outer casing
-inner and outer lining
-special design for small gas turbine engines and APU called reverse flow chamber
What are the two types cooling?
Film
transpiration
