POWERPLANT 2 Flashcards
Types of Jet Propulsion
Rocket
Ramjet
Pulsejet
Gas Turbine
A __________ is a non-air-breathing engine
that carries its own fuel and the oxygen
needed for the fuel to burn.
rocket
The two types of rockets
solid-propellant rockets
and liquid- propellant rockets
_____________ rockets use a solid fuel formed into a specific shape that promotes an optimum burning rate when mixed with an oxidizer.
Solid-propellant
__________ rockets are used primarily to propel some military weapons and occasionally to provide additional thrust for takeoff of heavily loaded aircraft.
Solid fuel
type of rocket which uses fuel and an oxidizing
agent such as liquid oxygen.
liquid-fuel rocket
A ________ is an athodyd (or aero-thermodynamic duct), an air-breathing engine with no moving parts.
ramjet
A _________ must be moving forward at high velocity before it can produce thrust. Their use is limited
ramjet
_______ engines are similar to ramjets except that the air intake duct is equipped with a series of shutter valves that are spring-loaded to the open position.
Pulsejet
A ______ is typically considered more useful than a ramjet because pulsejets can produce thrust prior to achieving a high forward speed
pulsejet
The ______________ is the most practical form of jet engine in use today.
gas turbine engine
has become the standard on nearly all commercial (transport category), business, and military aircraft.
turbine engine
4 TYPES OF GAS TURBINE ENGINE
Turbojet Engines
TurboPropeller Engines
Turboshaft Engines
Turbofan Engines
The basic operating principles of a ______________ are straightforward.
turbojet engine
A gas turbine engine that delivers power to a propeller is referred to as a ____________
turbopropeller, or turboprop engine.
_____________ are similar in design to turbo jet engines except that the power produced by a turboprop engine is delivered to a reduction gear system that spins a propeller.
Turboprop engines
________________ are used extensively in business and commuter aircraft because the combination of jet power and propeller efficiency provides good performance characteristics at speeds between 300 and 400 miles per hour
Turboprop engines
A gas turbine engine that delivers power to a shaft that can drive something else is referred to as a ____________.
turboshaft engine
Many helicopters use a __________ gas turbine
engine.
turboshaft
___________________ are widely used as auxiliary power units and, in industrial applications, to drive electrical generators and surface transportation systems
turboshaft engines
The output of a turboprop or turboshaft engine is measured by ___________ rather than thrust.
shaft horsepower
A ________________ consists of a multibladed, ducted propeller driven by a gas turbine engine.
turbofan engine
______________ were developed to provide a compromise between the best features of the turbojet and the turboprop.
Turbofans
A _____________ can have the fan mounted either in the front or back of the engine.
turbofan engine
Inlet air passing through a turbofan engine is usually divided into two separate ________________.
streams of air
One stream _______ through the engine core, and a second stream _____________ the engine core.
passes
coaxially bypasses
3 terms
thrust ratio
bypass ratio
fan pressure ratio.
A turbofan engine’s ______ ratio is a comparison of the thrust produced by the fan to the thrust produced by the engine core exhaust.
thrust
Turbofan’s _______ ratio refers to the ratio of
incoming air that bypasses the core to the amount of air that passes through the engine core.
bypass
Turbofans in civil aircraft are
generally divided into three classifications
based on bypass ratio:
low bypass
medium bypass
high bypass
low bypass ratio
1:1
medium bypass
2:1 or 3:1
high bypass
4:1 or greater
________________ determines a fan ‘s bypass ratio and thrust ratio.
Fan diameter
The ratio of air pressure leaving the fan to the air pressure entering the fan
fan pressure ratio
____________ is the ratio of a blade’s length to its width, or chord.
Aspect ratio
The seven basic sections of gas turbine engine
- Air inlet duct
- Compressor section
- Combustion section
- Turbine section
- Exhaust section
- Accessory section
The ___ section includes the
combustion, turbine, and exhaust sections.
hot
The _____ section includes the air inlet duct
and the compressor section.
cold
The ____________ provides a uniform supply of air to the compressor for efficient operation.
air inlet duct
The _____________ on a turbojet engine is normally considered part of the airframe, not the powerplant.
air inlet duct
the air inlet duct is located directly in front of the compressor and is mounted to the engine.
Engine-Mounted Inlets
Typically, ____________ inlet ducts are positioned near the wing root area.
wing-mounted
Engines mounted inside a fuselage typically use air inlet ducts located near the front of the fuselage.
Fuselage-Mounted Inlets
Some military aircraft use air inlet ducts mounted on the sides of the _________.
fuselage
A typical ________ air inlet consists of a fixed geometry duct with a diameter that progressively increases from front to back.
subsonic
__________ turbine engine inlets use a divergent profile to diffuse incoming ai r. At cruise airspeeds, the divergent shape causes air velocity to decrease and static air pressure to increase.
Subsonic
On ____________ aircraft, a typical air inlet duct has either a fixed or variable geometry with a diameter that progressively decreases, then increases from front to back.
supersonic
This convergent-divergent shape is used to slow the incoming airflow to subsonic speed before it reaches the compressor.
Supersonic Inlets
Many ____________________ employ a movable
plug or throat that changes duct geometry according to flight conditions.
supersonic inlet ducts
__________________ have a convergent profile that is designed for obtaining high aerodynamic efficiency when stationary or in slow flight.
Bellmouth inlet ducts
______________________ are typically used on helicopters, some slow-moving aircraft, and on engines being run in ground test stands.
Bellmouth inlet ducts
Prevention of __________________ is a top priority among turbine engine operators and manufacturers.
foreign object damage (FOD)
Several makes of helicopters and turboprop
aircraft use ___________ to help prevent
foreign object damage.
inlet screens
A convergent duct at subsonic speed?
P ↓ V ↑
A divergent duct at subsonic speed?
P ↑ V ↓
A convergent duct at supersonic speed?
P ↑ V ↓
A divergent duct at supersonic speed?
P ↓ V ↑
_______________ ducts are undivided and supply air to one engine only.
Single entry
__________ ducts can be two
separated inlets that supply one engine or
one intake internally divided to feed two
engines
Divided entry
An engine running at full power on
the ground creates a negative pressure
(suction) in the intake.
RAM RECOVERY
A gas turbine engine takes in a
quantity of air, adds energy to it, and then
discharges the air to produce thrust.
Compressor Section
The component forcing air into an
engine is the _____________
compressor
Task is to compress
the air and deliver it with correct volume
and velocity to the… combustion section.
compressors
Driven by the turbine/s, compressors
convert mechanical energy into kinetic
energy (velocity), potential energy
(pressure) and heat.
compressor
Three different types of compressors
Centrifugal
Axial
Centri-axial
The ______________ uses a
rotating impeller, a stationary diffuser
section and a manifold
centrifugal compressor
____________________ achieve the same
result as centrifugal compressors but do so
while maintaining airflow in an axial
direction through numerous stages.
Axial compressors
Axial compressor stages consist of
________ and _____________
rotors and stators.
A _____ is a rotating disc with blades
attached around the circumference.
Rotor
A _____ is a non-rotating set of blades
fixed into a shroud assembly.
Stator
The ________________________ uses a number of axial stages coupled to a final centrifugal stage.
centri-axial compressor
has better overall compression ratio than a centrifugal compressor but is less efficient than a purely axial compressor.
Centri-Axial Compressor
The ___________ converts kinetic
energy from the gas flow into mechanical
energy.
turbine section
