Module 2 Flashcards
is essentially a heat engine using air as a working fluid to provide thrust.
Gas turbine engine
To achieve this, the air passing through the engine has to be accelerated; this means that the (?) of the’ air is increased.
velocity or kinetic energy
To obtain this increase, the (?) energy is first of all increased, followed by the addition of (?) energy, before final conversion back to (?) energy in the form of a high velocity jet efflux.
- pressure
- heat
- kinetic
gases flowing through the exhaust nozzle. Also known as jet blast and Jet engine exhaust.
JET EFFLUX
For gas turbine engine, combustion occurs at a constant (?).
pressure
In a piston engine combustion occurs at constant (?).
volume
Both engines have induction, compression, combustion and exhaust. These processes occurs (?) on gas turbine engines.
continuously
Both engines have induction, compression, combustion and exhaust. For piston engines they occur (?).
intermittently (at intervals)
In piston engines, (?) is utilized for the production of power, the other strokes involve charging, compressing and exhausting of the working fluid.
only one stroke
The turbine engine eliminates the (?), thus enabling more fuel to be burnt in a shorter time; hence it produces a greater power output for a given size of engine.
three “idle” strokes
The turbine engine eliminates the three “idle” strokes, thus enabling more fuel to be burnt in a shorter time; hence it produces a greater (?) for a given size of engine.
power output
Due to the continuous action of the turbine engine and the combustion chamber is not an enclosed space, the pressure of the air does not (?). But on piston engines, volume (?).
- rise
- increases (heating at a constant pressure)
GTE
Under these conditions, there is (?) to be withstood.
no peak or fluctuating pressures
With the piston engine, the peak pressure is of (?).
1,000 lb/in2
Piston engine necessary to employ cylinders of (?) construction and to use (?) octane fuels.
- heavy
- high
Gas turbine engines use (?) octane fuels and (?) fabricated combustion chambers.
- low
- light
Because the turbo-jet engine is a heat engine, the (?) the temperature of combustion the (?) is the expansion of the gases.
- higher
- greater
The (?) must not exceed a value that gives a turbine gas entry temperature suitable for the design and materials of the turbine assembly.
combustion temperature
The use of (?) in the turbine assembly permits a higher gas temperature and a consequently higher thermal efficiency.
air-cooled blades
During the working cycle of the turbine engine, the (?) receives and gives up (?), so changes in its pressure, volume and temperature occur.
- airflow (working fluid)
- heat
These changes as they occur are closely related, for they follow a common principle that is embodied in a combination of the (?).
Laws of Boyle and Charles
This means that the product of the pressure and the volume of the air at the various stages in the working cycle is proportional to the absolute (?) at those stages.
temperature of the air
Whether energy is added by combustion or by compression, or is extracted by the turbine, the (?) is directly proportional to the work added or taken from the gas.
heat change
Law that pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.
BOYLE’S LAW
Law that the volume of an ideal gas at constant pressure Is directly proportional to the absolute temperature. (Zero Kelvin corresponds to - 273.15 degrees Celsius).
CHARLES’ LAW
The gas turbine engine is essentially a heat engine using air as a working fluid to provide thrust. To achieve this, the air passing through the engine has to be (1); this means that the velocity or kinetic energy of the air is increased. To obtain this increase, the (2)is first of all increased, followed by the addition of (3), before final conversion
back to kinetic Energy in the form of a high velocity (4).
- ACCELERATED
- PRESSURE ENERGY
- HEAT ENERGY
- JET EFFLUX
Combustion occurs at a
constant pressure
GAS TURBINE ENGINE
Combustion is continuous
GAS TURBINE ENGINE
Combustion occurs at a
constant volume.
RECIPROCATING ENGINE
Combustion is
intermittent
RECIPROCATING ENGINE
eliminates the three ‘idle’
strokes, thus enabling
more fuel to be burnt in a
shorter time; hence it
produces a greater power
output for a given size of
engine
GAS TURBINE ENGINE
only one stroke is utilized in the production of power, the others being involved in the charging, compressing
and exhausting of the working fluid.
RECIPROCATING ENGINE
Due to the continuous action of the turbine engine and the fact that the combustion chamber is not an enclosed space, the pressure of the air does not rise, like that of the piston engine, during combustion but its volume does increase. This process is known as heating at constant pressure (?).
Charles Law
Because the turbo-jet engine is a heat engine, the higher the
temperature of combustion the greater is the (?) of the gases.
expansion
The use of (?) in the turbine assembly permits a higher
gas temperature and a consequently higher thermal efficiency.
air-cooled blades
During the working cycle of the turbine engine, the airflow or ‘working fluid’ receives and gives up heat, so
producing changes in its (1).
These changes as they occur are closely related, for they follow a common principle that is embodied in a combination of the (2).
- pressure, volume and temperature
- laws of Boyle and Charles
Briefly, this means that the product of the
pressure and the volume of the air at the various stages in
the working cycle is proportional to the absolute
(?) of the air at those stages.
temperature
There are three main conditions in the engine working
cycle during which these changes occur.
compression
combustion
expansion
During (?), when work is done to increase the
pressure and decrease the volume of the air, there is a
corresponding rise in the temperature.
compression
During (?), when fuel is added to the air and
burnt to increase the temperature, there is a
corresponding increase in volume whilst the pressure
remains almost constant.
combustion
During (?), when work is taken from the gas
stream by the turbine assembly, there is a decrease in
temperature and pressure with a corresponding increase
in volume.
expansion
When the air is compressed or expanded at 100 percent
efficiency, the process is said to be (?).
ADIABATIC
(?) percent is good adiabatic efficiency for the compressor and turbine.
90 PERCENT
during compression, a rise in the (?) of the air is
required and not an increase in its velocity.
pressure
After the air has been heated and its internal energy
increased by combustion, an increase in the (?) of
the gases is necessary to force the turbine to rotate.
velocity
At the (?) a high exit velocity is required,
for it is the change in the momentum of the air that
provides the thrust on the aircraft.
propelling nozzle
Local decelerations of (?) are also required, as for
instance, in the combustion chambers to provide a low
velocity zone for the flame to burn
airflow
These various changes are effected by means of the size
and shape of the (?) through which the air passes on its
way through the engine.
ducts
These shapes apply to the (?) where
the airflow velocity is subsonic or sonic, i.e. at the
local speed of sound
gas turbine engine
The design of the (?) is of great
importance, for upon their good design will
depend the efficiency with which the energy
changes are effected.
passages and nozzles
Any interference with the
smooth airflow creates a loss in efficiency and
could result in component failure due to vibration
caused by (?) or turbulence of the airflow.
EDDIES
The path of the air through a gas turbine engine
varies according to the (?) of the engine.
design
The major difference of a turbo-propeller
engine TO GTEs is the (?).
conversion of gas energy into mechanical power to drive the propeller
Turboprop:
The majority of the energy in the gas stream is absorbed by additional (?), which drive the propeller through internal shafts
turbine stages
Turboprop:
Only a small amount of (?) is available from the exhaust system.
‘jet thrust’
the (?) involves a division of the airflow.
by-pass principle
Conventionally, all
the air taken in is given an
initial (?) compression and
a percentage is then ducted
to by-pass, the remainder
being delivered to the
combustion system in the
usual manner.
low
What is Newtons third Law of Motion?
LAW OF ACTION AND REACTION
The term used for each set of stators and rotors
AXIAL FLOW
This type of compressor incorporates an impeller
CENTRIFUGAL FLOW
He patented the first Jet Engine
RENE LORIN
Patented the first Gas Turbine Engine
FRANK WHITTLE
What does “Athodyd” mean?
AERO THERMO DYNAMIC DUCT
This type of Engine carries its own oxygen source
ROCKET ENGINE
What will happen to the temperature of air if the pressure inside the engine is increased?
AIR TEMPERATURE INCREASES
If temperature of air is increased, what is happening to the pressure?
AIR PRESSURE INCREASES
The term used for changing air temperature to produce a propulsive force
JET PROPULSION
Why are turbine engines more powerful than reciprocating engines?
TURBINE ENGINES ARE MORE POWERFUL THAN RECIPROCATING ENGINES BECAUSE THE COMBUSTION OF TURBINE ENGINES IS CONTINUOUSLY. IT CAN PROVIDE GREATER POWER OUTPUT. WHILE THE COMBUSTION OF RECIPROCATING ENGINES IS INTERMITTENTLY OR AT INTERVALS. IT CAN PROVIDE LOWER POWER OUTPUT THAN THE COMBUSTION OF TURBINE ENGINES THAT ARE GREATER.
Why did it take 11 years for the whittle engine to achieve its first flight?
IT TAKE 11 YEARS FOR THE WHITTLE ENGINE TO ACHIEVE ITS FIRST FLIGHT BECAUSE BY THEIR TIME, THEY NOT YET DISCOVERED THE OTHER ELEMENTS OR METALS SUCH AS TITANIUM, ALUMINUM AND THEIR ALLOYS.
What do we call the cycle in turbine engine?
Brayton Cycle
