Module 15.5 Combustion Section Flashcards
What are the two combustion chamber cooling methods?
- Transpiration
- Film
What are the 3 types of combustion chamber?
- Can-type
- Can-annular
- Annular
What are the 5 main requirements for a combustion chamber?
- Safe ignition
- Stable combustion
- Complete combustion
- Equal temperature distribution
- Min pressure loss
The combustion chamber should be?
- Small and light
- Dependable cooling
- High operating lifetime
What is the optimum air fuel ratio?
15:1
What is the percentage of secondary airflow?
70-80%
What is inside the casing? (Combustion chamber).
Flame tube
What is the function of the flame tube?
Control and guide the flame
What cools the flame tube?
Secondary airflow
what sprays the fuel into the centre of the airflow?
Fuel nozzle/injectors
Air is slowed before entering the combustion chamber to ensure what?
Complete combustion
What is the percentage of primary flow?
20-30%
What is the primary airflow used for?
The combustion process
What causes the vaporised fuel that is mixed with the air to combust?
Igniter plug
Where does secondary air flow into the flame tube?
Dilution/mixer zone
What are the advantages of can-type chambers?
- Simple design
- Good structural strength
- Removed and replaced individually
What is the difference between can-type and can-annular?
Can-annular, all of flame tubes share the same case
What are the 3 major parts of an annular combustion chamber?
- Dome
- Inner liner
- Outer liner
How many flame tubes are in an annular combustion chamber?
One
What vanes does the dome house? Regarding combustion section…
Fuel nozzle and swirl vanes
What is the special design for APU and Small GTE called?
Reverse flow
What are the 3 sections of an annular combustion chamber?
- Case
- Flame tube
- External components fitted to outer wall
What are the 3 components that make up a combustion case?
- Outer wall
- Inner wall
- Diffuser
What prevents air leaks in front of the inner wall flange?
Compressor Discharge Pressure (CDP) Seal
What are the vanes known as at the end of the HP compressor?
Exit guide vanes
How many igniters are found in an annular chamber?
Two
What does the flame tube dome section connect?
The inner and outer liner
What method of cooling is between the inner surface of the liners?
Film cooling
Where does the air go in transpiration cooling? (Secondary airflow)
Enters the flame tube by radial holes in the liner
What is a method of reducing emissions?
Dual dome
