turbine engines Flashcards
explain the main difference and advantage of a turbofan over a turbojet engine
a turbofan engine uses a fan to bypass some air around the engine core and to provide thrust. the advantage is that this provides additional thrust without increasing fuel flow
name the major components of a gas turbine engine
air inlet
compressor section
combustion section
turbine section
exhaust section
gearbox
accessory section
what determines the amount of airflow through a turbine engine?
the forward speed of the aircraft, compressor speed, and air density
name the two types of compressors commonly used in turbine engines
axial and centrifugal flow
name two different methods for attaching turbine engine rotor blades to the rotor disks
dovetail
root
bulb
fir-tree
what are the different types of combustion chambers used in turbine engines
can
annular
can-annular
reverse flow annular
what is a split compressor system
also called dual or twin spool compressors. these are connected to the turbine section with two rotor shafts, one inside the other
what prevents the combustion chambers from burning
cooling air along the inside of the liner
what is the purpose of the interconnecting tubes attached between the can-type combustion chambers
for flame propagation during engine start
what functions do axial flow turbine nozzles perfom
they direct the mass airflow to drive the turbine rotor at a specific angle
how is thermal stress relieved on a turbine disc
by directing bleed air onto the face of the disk, or by grooves being cut in the disk
what are carbon seals used for in turbine engines
they are used as oil seals for the rotor shaft bearings
what is shaft horsepower
it is an indication of the torque developed by a turboprop or turboshaft engine
when a turbofan or turbojet engine is shut down what should the mechanic listed for during coast-down
any rubbing sound or other unusual noises from the engine
what are the desired effects of turbine engine of turbine engine compressor field cleaning
removal of contaminant deposits from interior engine surfaces and improved engine performance
what methods are commonly used to accomplish turbine engine compressor field cleaning
fluid wash and abrasive grit blast
what type of compressor blade damage may be found when inspecting compressor blades
dents
galling
pitting
cracks
scratches
burrs
burns
gouges
what is used to mark both hot and cold section parts for repair
layout dye, commercial felt tip marker, or chalk
what is the effect of relative humidity on a turbojet or turbofan power
negligible, no effect
what may be the indications if a turbojet or turbofan engine is out of trim
the engine has high exhaust gas temperature at the target engine pressure ration for takeoff power
what would the possible cause be for a turbojet or turbofan engine having high exhaust gas temperature, low RPM, and high fuel flow at all engine pressure ratio settings
possible turbine damage or loss of turbine efficiency
