15.5 Combustion Chamber

Question 1

What is the key function of the combustion chamber?

Answer 1

-Provides the energy needed to power the turbine
-safe ignition
-stable combustion
-complete combustion
-equal temperature distribution at combustion outlet
-minimise pressure loss

Question 2

What must the combustion chamber be?

Answer 2

-small and light
-dependable cooling system
-high operating lifetime

Question 3

How much air travels to primary and secondary airflow?

Answer 3

Primary - 20/30%
Secondary - 70/80%

Question 4

What is the optimum air fuel mix?

Answer 4

15:1

Question 5

What is the flame tube?

Answer 5

It control and guides the flame

Question 6

What is the combustion chambers function?

Answer 6

-takes air pressure loads
-fuel vaporising
-supports the flame tube

Question 7

What are the basics of combustion?

Answer 7

Fuel air mixture injected
Fuel is vaporised
It is electrically ignited to start the engine

Question 8

What is the purpose of the primary and secondary airflow?

Answer 8

Primary is combustion
Secondary mixes with hot gas in the dilution zone

Question 9

What are the uses for can type and disadvantages?

Answer 9

-APU
-centrifugal compressor
They are heavy requiring a lot of space and have complicated ducting

Question 10

What is the structure of can annular and its design?

Answer 10

-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

Question 11

Annular combustion chamber design and structure?

Answer 11

-inner and outer casing
-inner and outer lining
-special design for small gas turbine engines and APU called reverse flow chamber

Question 12

What are the two types cooling?

Answer 12

Film
transpiration