34 Questions
The force that the gasturbine excerts on the air flowing through is ... (1) the force that the air excerts on the gasturbine, and points towards the ... (2) of the aircraft.
(1) equal to; (2) tail
The propulsive efficiency is the ratio between the power absorbed by (1) ... and the power delivered by the (2) ... .
(1) airplane; (2) engine
What stays the same in a closed system ?
Mass
What processes take place in the Carnot-cycle of a Stirling engine ?
isothermal and adiabatic
The main advantages of a jet engine over a reciprocating engine are related to the:
airflow
How does the First Law look like, when applied to the turbine of a gasturbine ?
ΔH0 = -W
Friction losses result in ... (1) of the ... (2) of a gas.
(1) an increase; (2) entropy
The purpose of flat-rated thrust is to:
increase the life of critical components
Due to the decreasing blade length at the end of the compressor, we can also reduce the cross-section of the compressor. This can be done either by increasing the diameter of the shaft, or by decreasing the diameter of the casing of the compressor. What are two benefits of the increase of the diameter of the shaft ?
a better connection to the turbine and better control of the tip clearance
What conclusion can you draw if the degree of reaction of a stage increases ?
The pressure build-up over the rotor increases relative to that of the stator
The goal of the VSVs is to prevent:
stall at a low thrust setting
The blade profiles shown are from of the (1) ... of (2) ... turbine.
(1) rotor; (2) an impulse
A stoichiometric mixture contains ... combustion takes place.
just enough fuel so that complete
A flow divider in a combustion chamber is used to:
ensure a stable output pressure of the atomizer
I The starting engine of a twin-spool turbofan is connected to the N2-shaft II The starting engine drives the gas turbine by delivering air under pressure to the gas turbine
I is right, II is wrong
What line represents the fastest deceleration from Y to X ?
d
A fuel metering graph is given at sea level: If we fly at 10 km altitude (where a significantly lower temperature prevails) then the equilibrium line moves to the (1)...; the prohibited areas related to a too high fuel-air ratio move (2) ...; and the prohibited areas related to a too low fuel-air ratio move (3) ...
(1) left; (2) down; (3) up
In what order were the following systems for fuel metering developed ?
MEC – PMC – FADEC
One has switched from controlling N2 to controlling N1 because the N1-shaft:
gives the best indication of the power delivered
What does FADEC do if both systems of the ECU give error messages?
Each error message is given a score. The system with the lowest totaI score is used.
With the increase of the velocity of the air and the mass flow of the air in an unchoked turbojet the ... can be determined. I. thrust II. propulsive efficiency
I is right, II is wrong
In each cylinder the gas is in a different phase of the Otto-cycle. When the gas in cylinder number 4 has just been ignited and is expanding, in cylinder number 1 the gas:
enters the cylinder
In a reciprocating engine the pressure of the gas is increased by compressing the gas in the piston VERY quickly. Hereby:
the temperature of the gas increases
A ... has the acceleration of the gas flow as its ONLY source of propulsion.
turbojet
If the TAS increases, the total efficiency ... (1) because of a change in the ... (2) efficiency.
(1) increases; (2) propulsive
The critical pressure increases with the ... of the outlet.
increase of the total pressure of the gas at the beginning
Why does increasing the TIT have a favourable effect on the specific thrust?
More fuel can be supplied to 1 kg of air
To determine the pressure difference, in the rotor you look for the change of the (1) ... velocity, and in the stator for the change of the (2) ... velocity.
(1) relative; (2) absolute
We talk about choke when ... occurs.
a too large axial velocity of the airflow
Compared to a turbine blade a compressor blade has a:
larger wrong
With impingement cooling air:
is blown against the inside wall of the blade
To the combustion chamber a surplus of air is fed. What is NOT a function of this surplus of air?
To ensure complete combustion of the fuel in the primary zone
What type of combustion chamber is the LEAST suitable for connection to a centrifugal compressor ?
Annular
What is first parameter that begins to rise at the startup of the engine?
N2
Test your knowledge of gas turbines and jet engines with this quiz. Questions cover topics such as propulsive efficiency, the First Law applied to turbines, Carnot cycle in Stirling engines, and advantages of jet engines over reciprocating engines.
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