LESSON # 7 Flashcards
The (?) carried a proportion of the primary combustion air with
the injected fuel.
Spray Nozzle
By aerating the spray, the local (?) concentrations produced by other types of burner are avoided, thus giving a reduction in both carbon formation and exhaust smoke.
fuel-rich
An additional advantage
of the spray nozzle is
that the low pressures
required for (?)
of the fuel permits the
use of the comparatively
lighter gear-type pump.
atomisation
This type of burner presents the fuel in the combustion system in the form
of a rich fuel vapour or gas.
VAPORISING BURNERS
This is achieved by delivering the metered
flow of fuel to “J” shaped vaporising tubes, which protrude into the combustion chamber.
VAPORISING BURNERS
The fuel passes down the vaporising tubes in a coarse spray and mixes
with the primary air that enters concentrically to the (?).
fuel supply pipe
The fuel and air is mixed thoroughly by (?) that protrude into the primary
airflow and the heat of the flame surrounding the tube causes the mixture to vaporise before it emerges in the combustion chamber.
pins
The introduction of the primary air into the vaporising tubes aids the
process of vaporisation and also helps to cool the tubes to prevent the
(?).
formation of carbon
With this type of burner, the flame points towards the incoming airflow
and this helps to stabilise the flame in the vaporising tubes, preventing it being blown away by the secondary air, thus allowing a relatively short combustion system.
VAPORISING BURNERS
Fuel Metering System
The advantages of this type are:
a. Pre-vaporising gives complete combustion within a short length of
flame tube.
b. A complete ring of flame around the annular chamber.
c. Even pressure and temperature around the chamber.
This (?) is fitted on the starting fuel feed line.
solenoid valve
It is a two-position valve spring loaded to the closed position.
solenoid valve
During starting, the (?) is energised and the valve opens.
solenoid
The flow is directed to the check valve. During the (?) the solenoid is de-energised and the spring force closes the valve and the fuel flow to check valve is stopped.
end of the cycle (shut down)
A (?) is fitted in the starter jet line downstream of the Priming
Solenoid Valve to prevent fuel dribbling into the combustion chamber on shut down.
check valve
It is a spring-loaded
valve, which is closed at
rest and opens when fuel
pressure reaches a pre-
determined value.
Check Valve
As vaporisers do not atomise the fuel sufficiently for combustion until they
become heated, for starting purposes initial heating during start is provided
by four jets, two of which are combined with (?).
High Energy Igniters
The (?) ensure
that, even at the low
flows encountered
during start, the fuel is
atomised as required for
light up.
starter jets
A (?) is fitted in the main gallery feed line.
Pressurising Valve
It is spring-loaded which functions to build up and stabilise the metering system servo pressures before any flow to the main gallery.
Pressurising Valve
Thereby it ensures the
correct delivery of fuel to the vaporisers during start.
Pressurising Valve
The (?) connects with delivery tubes, each feeding one vaporiser head through a distribution orifice.
main gallery
The (?) are fitted in pairs on the combustion chamber outer case.
delivery tubes
Fuel is mixed with air in the (?).
vaporiser tubes
As the mixture passes
through the heated tube, the fuel becomes (?) so that it is delivered in combustible form.
vaporised
A (?) houses the check and pressurising valves.
single unit
A purge flow tapped upstream the pressurising valve is connected to the
check valve via a (?).
purge restrictor
This ensures a continued fuel flow
through the starter jets to avoid formation of carbon in this area.
purge restrictor
EEC
electronic engine controls
These demands are met by electronic engine controls, or EEC, of which
there are two types:
- Supervisory
- full-authority
Advances in gas turbine
technology have
demanded more precise
control of (?) than cannot
be provided by hydro
mechanical fuel controls
alone.
engine
parameters
