15.5, 15.6, 15.11 Flashcards
3 types of airflow in a combustion chamber
Primary ( mixes with gas)
Secondary
Tertiary ( cools )
Purpose of snout
Slows airflow within combuster
Purpose of interconnectors
Ensures combustion is spread to all cans
Reverse flow combustion chamber
Used on turbo prop and some business jet engines
Flow enters from the rear
Function of turbine
Transform kinetic and heat energy into mechanical work
2 types of turbine
Axial flow , radial flow
Purpose of turbine nozzle guide vanes
Direct gasses from combuster onto turbine and turbine blades
3 types of turbine blades
Reaction , impulse , impulse reaction
Difference in convection and film cooling
Convection involves compressor discharge air
3 creep phases
Primary
Secondary
Tertiary ( worst )
Material of turbine blades
Super alloys , nickel based alloys
Single crystal blade
Modern type of aircraft blade construction , has good resistance to fatigue and cracking
Purpose of tip sealing
Stop air leaking over blade tip which will reduce efficiency
Material of turbine blades
Nimonic alloys , nickel based alloys
FADEC
full authority digital engine control
Uses sensors to monitor engine condition
2 types of atomising fuel nozzles
Simplex , duplex
What can sudden deceleration of an engine cause
Engine flame out
Purpose of FCU ( fuel control unit )
Deliver correct amount of fuel
EEC
Electronic engine control
2 fuel pumps
Plunger type ( variable delivery ) Spur gear type ( constant delivery)
2 types of fuel nozzles
Pressure atomising nozzle
Vaporising nozzle
P and D valve?
Pressurising and dump
Valve
