15.5 Flashcards
(25 cards)
What are the two main components of a combustion chamber
Combustion chamber casing
Flame tube (found inside casing)
What is the role of the combustion chamber casing
Support the flame tube
House fuel nozzles and igniter plugs
What is the fuel are radio
Air:fuel
15:1
When are igniters used
Used on start until the engine becomes self sufficient and then they shut off
They are turned on before the fuel flow starts
What percentage of air flows through the flame tube and what is this air known as
20 to 30%
Known as primary air
What is the percentage of air that flows around the flame tube but within the combustion casing
70 to 80%
Known as secondary airflow
Where would you find a can type combustion chamber
Old gas turbines with centrifugal compressors
What are the disadvantages of the can type combustion chamber
Heavy and needs a lot of space also needs complex air supply ducts
Own flame tubes as casing
What combustion chamber is this
Can type
What are the advantages of the can type combustion chamber
simple in design, they have very good structural strength and they can be removed and replaced individually
All the flame tubes have a common outer casing and inner casing
Which combustion chamber is this
Can annular
What are the advantages and disadvantages of the can annular combustion chamber
The advantage of the can-annular combustion chamber is that it is smaller and lighter than a similar multiple-can-type combustion chamber.
The disadvantage of this type is that the aerodynamic losses are quite high and the ignition from one flame tube to the other is very difficult.
How many casings does a annular combustion chamber have
One casing that runs the hole circumference of the engine
What are the three main components of an annular combustion chamber
Dome
Inner liner
Outer liner
What type of combustion chamber is used on APUs and small engines
Reverse flow combination chamber
Which case houses the fuel nozzles in an annular combustion chamber
Outer
What are the disadvantages of an annular combustion chamber
Expensive to make and difficult to remove
How many and where are the ignator plugs on an annular combustion chamber
Two on the lower half of the combustion case
What makes up the flame tube assembly on an annular combustion chamber
Outer and inner liner
Outer and inner cowl
Dome
What is film cooling in combustion chambers
Creating a film of cooling air over flame tube
What is transpiration cooling in annular combustion chamber
Most sophisticated
Air flows between the liner segments
What pollutants does a gas turbine engine produce if fuel in not fully burnt
Hydrocarbons, carbon monoxide and nitrogen
What will happen if there is an excessive amount of fuel in the engine
Carbon monoxide build up
What would a low and high combustion temperature cause
Low increases carbon monoxide
High decreases carbon monoxide but increases nitrogen
