1 Flashcards
What Engine provides?
- bleed air
- hydraulic
- engine thrust
4 types of gas turbine engine
- turbo fan
- turbojet
- turboprop
- turboshaft
thermodynamic cycles used in gas turbine engine
Brayton cycle
Principle of jet propulsion is based on
Newton’s third law of motion
thrust produced by the fan, thrust produced by the core engine
Thrust produced by a turbofan engine
Turbofan has
primary airflow (core engine) and secondary airflow
ratio of the secondary and primary airflow
Bypass ratio
Construction of turbine
- modular
- non-modular
no rebalancing is required
Modular
requires rebalancing
Non-modular
protects the combustion section and high turbine section from heat
and corrosion
Ceramic coating
have same strength with steel-based alloy but half as heavy as steel-based alloy
Titanium-based alloys
3 main section of Gas Turbine Engine
compressor, combustion, turbine
Major component in Gas Turbine Engine drives the compressor and accessory gearbox
Turbine
Two kinds of ducting
- divergent duct
- convergent duct
airflow velocity decreases, pressure and temperature increase
Divergent duct (narrow to wide)
airflow velocity increases
Convergent duct (wide to narrow)
increases the velocity at the exhaust
Jet nozzle
Working Cycle of a Gas Turbine Engine
induction, compression, combustion, expansion
part of the engine where temperature and pressure is measured
Engine station numbers
the effect if there’s a high pressure ratio
High EGT
amount of fuel the engine needs to make 1kN of thrust in 1hr
Thrust specific fuel consumption
only used for few minutes due to so much stressed produced to the engine
TOGA (Take off Go around)
fixed limitation for maximum thrust of engine
Flat rating
red stripe warning placard
Danger zone
Engine mounted on a supersonic airplane must convert the flow of air to subsonic by
having normal shockwave or oblique shock wave or multiple oblique shock wave on its inlet.
Aircraft is still possible to be released even with defective anti-ice valve (must be locked open, or locked close)
– keeps the fan blades deflection within limits during heavy vibration or FOD
Midspan shroud
– measure the weight of the fan blade, distance of center of gravity of the blade, measure from CG to axis of rotation
Moment weight
– used to compensate the moment weight difference of the fan blades; used to lower N1 vibration
Balance weight/balance screw
Installation of compressor rotor blade
axial dovetail slots, circumferential, bolts
Part of combustion chamber
flame tube, casing
Continuous supply of fuel & air
maintains the combustion
Air in the combustion chamber
for cooling, for combustion
– multiple flame tubes
Can type & can-annular type
– used for inspection in the combustion chamber
Borescope
– transfer of flame
Interconnection tube
– accelerates the airflow in the turbine
Nozzle guide vanes
– damage due to application of centrifugal loads
Creep
Why does turbine blade rotate?
Because of the impact of the air flow coming from the nozzle guide vanes
– turbine rotates due to the airflow’s impact coming from the nozzle guide vanes
Impulse turbine
– turbine rotates due to the airflow’s impact coming from nozzle guide vanes, and because of the accelerated airflow of the rotor
Impulse reaction turbine
– turbine rotates due to the airflow’s impact coming from nozzle guide vanes, and because of the accelerated airflow of the rotor
Impulse reaction turbine
Part of the engine with clearance control
HPT LPT HPC
Turbine case cooling system
active & passive
Where is the engine mounted
turbine frame (aft mount), fan frame (fwd mount)
How does the thrust reverser work
deflects the rearward airflow in the opposite direction
Main parts of accessory drive system
internal gearbox, transfer gearbox, accessory gearbox, radial and horizontal driveshaft
There are either one (1) or two (2) Accessory gearbox (depends)
Two gearbox
high speed, low speed
– gearbox driven by LP rotor
Low speed gearbox
Installation of accessory gearbox
bolted, v-clamp, QAD ring
Accessory gearbox location?
is located on the side or below the engine
– used to seal the gap between the bearing compartment walls and the engine shaft
Carbon seal
Types of bearing
– ball bearing, roller bearing
– equalize the two axial loads in the opposite direction; reduce the
axial loads to the fixed bearing
Pressure balancing
Two ways of (bearing) lubrication
– direct lubrication, under race lubrication
Two types of lubricants/oils
– synthetic, mineral
Synthetic oils are impossible to mixed
– returns the oil from the bearing compartments and the gearboxes to the oil tank
Scavenge system
– oil quantity, oil pressure, oil temperature, low oil pressure switch, filter clogging switch
Oil monitoring system sensors
– quantity, temperature, pressure (measured by oil monitoring system)
Information of the oil system that is always displayed
– located above the oil tank. No need to drain the oil tank when replacing an oil quantity transmitter
Oil quantity transmitter
– has two tube connections; pressure difference between the total pressure in the supply line and the vent pressure in the supply pump.
Oil pressure transmitter
Oil temperature system is installed in scavenge line or supply line
How many component monitors the oil pressure
2
– located can either be on supply line or scavenge line
Oil temperature sensor
– used to determine if fuel is contaminated
SOAP analysis
