Dale Crane Q's Flashcards
The pressure of moving gas is a measure of ______ energy (potential or kinetic)
potential
The velocity of moving gas is a measure of its ________ energy (potential or kinetic)
kinetic
Force is a vector quantity that has both ______ and _____
direction
magnitude
Work is the product of _______ and ______
force
distance
Power is the rate at which _____ is done
work
The rate at which an object is travelling in a given direction is the _______ (speed or velocity) of the object
velocity
Bernoulli’s principle explains that if energy is neither added to nor taken from a body of moving fluid, any increase in its velocity will result in a corresponding ________ (increase or decrease) in its pressure
decrease
When air flows through a converging nozzle at a subsonic speed, its velocity will ________ and its pressure will ________
(increase or decrease)
When air flows through a converging nozzle at a subsonic speed, its velocity will increase and its pressure will decrease
When air flows through a converging nozzle at a supersonic speed, its velocity will _______ and its pressure will ______
(increase or decrease)
When air flows through a converging nozzle at a supersonic speed, its velocity will decrease and its pressure will increase
When air flows through a diverging nozzle at a subsonic speed, its velocity will _______ and its pressure will _______
(increase or decrease)
When air flows through a diverging nozzle at a subsonic speed, its velocity will decrease and its pressure will increase
When air flows through a diverging nozzle at a supersonic speed, its velocity will _______ and its pressure will _______
(increase or decrease)
When air flows through a diverging nozzle at a supersonic speed, its velocity will increase and its pressure will decrease
An exhaust nozzle that prevents gases from flowing through it faster than the speed of sound is said to be a ______ nozzle
choked
The function of the turbine in a turbojet engine is to drive the ______
compressor
The six basic components in a turbojet engine are the:
- Air intake
- compressor
- diffuser
- combustor or burners
- turbine
- Tailpipe and jet nozzle
The portion of a turboprop engine that produces the hot gases that drive the turbines is called the _____ engine
core
A turboprop engine that uses a separate turbine to drive the propeller reduction gearing is called a/an ______ engine
free-turbine
A gas turbine engine used to drive the transmission of a helicopter is called a/an _____ engine
turboshaft
Three advantages of a turbofan engine over a turbojet engine are:
- Increased propulsion efficiency (fuel burn to useful thrust)
- lower noise level
- lower specific fuel consumption ( amount of fuel burned in one hour to produce one unit of thrust)
The ratio of the amount of air that passes through the fan to the amount of air that flows through the core engine is called the _____ ratio of the engine
bypass
The thermodynamic cycle of a gas turbine engine is the ______ cycle
Brayton
The Brayton thermodynamic cycle is the constant ________ (pressure or volume) cycle
pressure
The thrust produced by a turbofan engine is the sum of the thrust produced by the _______ and that produced by the ______
core engine
fan
An increase in the airspeed, with all else remaining the same, will cause turbine engine thrust to ________
(increase or decrease)
decrease
An increase in temperature of the inlet air, with all else remaining the same, will cause turbine engine thrust to ________
(increase or decrease)
decrease
An increase in the pressure of the inlet air, with all else remaining the same, will cause turbine engine thrust to _________ (increase or decrease)
increase
An increase in altitude will cause turbine engine thrust to ________ (increase or decrease)
decrease
(density factor greater than low temp factor)
An efficient cruising altitude for a turbojet- or turbofan powered aircraft is near 36,000 feet.
Above this altitude, the thrust produced by the engine ________
(increases or drops off more rapidly)
drops off more rapidly
An increase in ram effect, with all else remaining the same, will cause turbine engine thrust to _______
(increase or decrease)
increase
The speed of the high-pressure compressor in a dual-compressor turbofan engine is called _______
(N1 or N2)
N2
A pressure identified as Pt2 is ________ (static or total) pressure measured at the __________ (compressor or turbine) ________ (inlet or outlet)
static
compressor
inlet
What is customer bleed air?
Air that is tapped off a turbine engine compressor and used for such airframe functions as air conditioning and pressurisation. (not engine related stuff)
What are inlet guide vanes?
Inlet guide vanes are a set of stator vanes in front of the first stage of compression in a gas turbine engine
The two sections into which a gas turbine can be divided are the ________ section and the _______ section
cold
hot
The inlet ducts are actually part of the _______ (airframe or engine)
airframe
Inlet ducts for turbine engines may be divided into two classifications according to the speed of the aircraft on which they are installed. These are:
- Subsonic
- Supersonic
Most subsonic inlet air ducts are _________ (convergent or divergent)
divergent
The airspeed at which the ram effect of the air flowing into a divergent inlet air duct causes the pressure at the front of the compressor to be the same as the ambient pressure is called the ________ speed
ram recovery
Supersonic inlet ducts are of the __________ type
(convergent, divergent, convergent-divergent)
convergent-divergent
When supersonic air flows through the convergent portion of a CD duct, its velocity ______
(increases or decreases)
decreases
When supersonic air flows through a CD inlet duct, its velocity at the compressor inlet is _________
(subsonic or supersonic)
subsonic
Energy added to the air by a compressor initially increases the ______ of the air
(pressure or velocity)
velocity
The velocity of the air passing through a compressor is a measure of its ________ energy
(kinetic or potential)
kinetic
The pressure of the air passing through a compressor is a measure of its ______ energy
(kinetic or potential)
potential
After passing through the compressor, the air flows through a diffuser, which converts some of the _______ energy into pressure energy
velocity / kinetic
Two types of compressors used in gas turbine engines are ______ and ______ compressors
centrifugal
axial flow
The three components of a centrifugal compressor are:
- Impeller
- Diffuser
- Manifold
The ducts in the (compressor) diffuser are _______
(convergent or divergent)
divergent
A centrifugal compressor that has vanes on both sides is called a/an ________ compressor
double-entry
A centrifugal compressor that has vanes on both sides is called a/an _______ compressor
double-entry
The stators used with an axial-flow compressor cause the air to _______ (speed up or slow down)
slow down
After the air leaves the compressor, it flows through a/an _____ before it enters the combustion area
diffuser
The overall compression ratio of an axial-flow compressor is _______ (higher or lower) than that of a centrifugal compressor
lower
The blades of an axial-flow compressor can stall if the angle of attack becomes too ______ (high or low)
high
Two variables that affect the angle of attack of a compressor rotor blade are:
- Compressor Rotational speed (RPM)
- Velocity of the air through the compressor
The direction of the air entering the first stage of an axial-flow compressor is changed by the __________ so that it enters at the correct angle
inlet guide vanes
Two design features that may be used to prevent or minimize compressor stalls are:
- Variable inlet guide vanes
- Interstage bleed valves
An axial-flow compressor that has two separate compressors, each driven by its own turbine, is called a/an ________ compressor
dual-spool
The rearmost compressor in a dual-spool engine is the ______-pressure compressor
(high or low)
high
The low-pressure compressor is called the _______ compressor
(N1 or N2)
N1
The ratio of the mass of air moved by the fan to the mass of air moved by the core engine is called the ________ of a turbofan engine
bypass ratio
The angle of the inlet guide vanes is variable on some engines. The angles are changed hydraulically by the ________
fuel control
The air that flows through the combustion section but is not used in the combustion process is used for _____
cooling
Three types of combustors
- Annular
- Can-annular
- Multiple-can
A combustion in which the air leaving the compressor makes a 180^ turn, flows through the combustor, and makes another 180^ turn before it flows through the turbine, is a/an _______ combustor
reverse-flow
The air used in the combustion process is called ________ air
primary
There are normally ________ (how many) igniters used to ignite the fuel-air mixture in a gas turbine engine
2
The fuel-air mixture in cans not having an ignitor is ignited by flames from the other cans that travel through _____________
flame propagation tubes
A combustion section that has individual cans, but in which the hot gases from all of the cans are collected before they go to the turbine, is called a/an ______ combustor
can-annular
When the length of an engine must be kept as short as possible, a/an _______ combustor can be used
reverse-flow
The greater portion of the energy released from the fuel in a turbojet engine is used _________ (for thrust or to drive the compressor)
to drive the compressor
Turboprop and turboshaft engines use additional stages of ______ to produce the shaft horsepower needed to drive the propeller or helicopter rotors
turbines
The type of turbine used in a gas turbine engine is the _________ type
(axial or radial inflow type)
axial
The stationary vanes in a turbine section are located in the airflow path _______ the turbine rotors
(before or after)
before
The component in the turbine section that directs hot gases from the combustion section into the turbine is the ringe of turbine ______ or _____
guide vanes or nozzles
When gases flowing through a turbine nozzle can no longer accelerate, the nozzle is said to be operating in a/an ______ condition
choked
The point in a gas turbine engine at which the temperature is the highest is the _________
turbine inlet
The turbine inlet guide vanes form a series of __________ nozzles (convergent or divergent_
convergent
Three things the turbine inlet guide vanes do to the air as it passes through them are:
- increase its velocity
- decrease its pressure
- change its direction
Turbine disks are normally made of a _______ alloy
nickel
Turbine blades are normally attached to the disk by the _______ method
fir-tree
Three types of turbine blades are:
- reaction
- impulse
- reaction-impulse
When the hot gases drive an impulse turbine, their direction is changed, and their speed is ________
(increase, decreases, or remains the same)
remains the same
When the hot gases drive a reaction turbine, their direction is changed, and their speed _______
(increases, decreases, or remains the same)
increases
What orifice(s) is the image from?
What is the following orifice(s) from?
What is a flow divider?
A component in a turbine engine fuel system that routes all of the fuel to the primary nozzles or primary orifices when starting the engine or when the RPM is low
