Gasturbine Performance exams
MORE THAN 200 UPDATED QUESTIONS!
2019/2020
,1. 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.
a. (1) equal to; (2) nose
b. (1) equal to; (2) tail
c. (1) larger than; (2) nose
d. (1) larger than; (2) tail
2. The propulsive efficiency is the ratio between the power absorbed by (1) ... and the power
delivered by the (2) ... .
a. (1) airflow; (2) fuel
b. (1) airflow; (2) engine
c. (1) airplane; (2) fuel
d. (1) airplane; (2) engine
3. What stays the same in a closed system ?
a. Enthalpy
b. Entropy
c. Internal energy
d. Mass
4. What processes take place in the Carnot-cycle of a Stirling engine ?
a. adiabatic and isobaric
b. isobaric and isochoric
c. isochoric and isothermal
d. isothermal and adiabatic
5. The main advantages of a jet engine over a reciprocating engine are related to the:
a. airflow
b. construction costs
c. materials having a better heat resistance
d. materials having a higher mechanical strength
6. How does the First Law look like, when applied to the turbine of a gasturbine ?
a. ΔH0 = Q
b. ΔH0 = -Q
c. ΔH0 = W
d. ΔH0 = -W
7. Friction losses result in ... (1) of the ... (2) of a gas.
a. (1) a decrease; (2) entropy
b. (1) a decrease; (2) total enthalpy
c. (1) an increase; (2) entropy
d. (1) an increase; (2) total enthalpy
8. The purpose of flat-rated thrust is to:
a. increase the life of critical components
b. reduce the fuel comsumption
,c. be able to take off from a shorter runway
d. be able to take off from a runway at a higher elevation
9. 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. a better connection to the turbine and better control of the tip clearance
b. a higher possible pressure ratio and more room for accessories
c. better control of the tip clearance and a higher possible pressure ratio
d. more room for accessories and a better connection to the turbine
10. What conclusion can you draw if the degree of reaction of a stage increases ?
a. The pressure build-up over the stage is larger
b. The pressure build-up over the stage is smaller
c. The pressure build-up over the rotor increases relative to that of the stator
d. The pressure build-up over the rotor decreases relative to that of the stator
11. The goal of the VSVs is to prevent:
a. damage in the HDT
b. a flame-out in the combustion chamber
c. stall at a high thrust setting
d. stall at a low thrust setting
12. The blade profiles shown are from of the (1) ... of (2) ... turbine.
a. (1) rotor; (2) a 50% reaction
b. (1) rotor; (2) an impulse
c. (1) stator; (2) a 50% reaction
d. (1) stator; (2) an impulse
13. A stoichiometric mixture contains ... combustion takes place.
a. a surplus of fuel so that incomplete
b. a surplus of nitrogen so that no
c. a surplus of oxygen so that complete
d. just enough fuel so that complete
, 14. A flow divider in a combustion chamber is used to:
a. drain the fuel when only a small mass flow is required
b. drain the fuel when the engine is turned off
c. ensure a stable output pressure of the atomizer
d. not let the mass flow rate fluctuate too much
15.
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
a. I is right, II is right
b. I is right, II is wrong
c. I is wrong, II is right
d. I is wrong, II is wrong
16. What line represents the fastest deceleration from Y to X ?
a. A
b. B
c. C
d. D
17. A fuel metering graph is given at sea level:
MORE THAN 200 UPDATED QUESTIONS!
2019/2020
,1. 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.
a. (1) equal to; (2) nose
b. (1) equal to; (2) tail
c. (1) larger than; (2) nose
d. (1) larger than; (2) tail
2. The propulsive efficiency is the ratio between the power absorbed by (1) ... and the power
delivered by the (2) ... .
a. (1) airflow; (2) fuel
b. (1) airflow; (2) engine
c. (1) airplane; (2) fuel
d. (1) airplane; (2) engine
3. What stays the same in a closed system ?
a. Enthalpy
b. Entropy
c. Internal energy
d. Mass
4. What processes take place in the Carnot-cycle of a Stirling engine ?
a. adiabatic and isobaric
b. isobaric and isochoric
c. isochoric and isothermal
d. isothermal and adiabatic
5. The main advantages of a jet engine over a reciprocating engine are related to the:
a. airflow
b. construction costs
c. materials having a better heat resistance
d. materials having a higher mechanical strength
6. How does the First Law look like, when applied to the turbine of a gasturbine ?
a. ΔH0 = Q
b. ΔH0 = -Q
c. ΔH0 = W
d. ΔH0 = -W
7. Friction losses result in ... (1) of the ... (2) of a gas.
a. (1) a decrease; (2) entropy
b. (1) a decrease; (2) total enthalpy
c. (1) an increase; (2) entropy
d. (1) an increase; (2) total enthalpy
8. The purpose of flat-rated thrust is to:
a. increase the life of critical components
b. reduce the fuel comsumption
,c. be able to take off from a shorter runway
d. be able to take off from a runway at a higher elevation
9. 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. a better connection to the turbine and better control of the tip clearance
b. a higher possible pressure ratio and more room for accessories
c. better control of the tip clearance and a higher possible pressure ratio
d. more room for accessories and a better connection to the turbine
10. What conclusion can you draw if the degree of reaction of a stage increases ?
a. The pressure build-up over the stage is larger
b. The pressure build-up over the stage is smaller
c. The pressure build-up over the rotor increases relative to that of the stator
d. The pressure build-up over the rotor decreases relative to that of the stator
11. The goal of the VSVs is to prevent:
a. damage in the HDT
b. a flame-out in the combustion chamber
c. stall at a high thrust setting
d. stall at a low thrust setting
12. The blade profiles shown are from of the (1) ... of (2) ... turbine.
a. (1) rotor; (2) a 50% reaction
b. (1) rotor; (2) an impulse
c. (1) stator; (2) a 50% reaction
d. (1) stator; (2) an impulse
13. A stoichiometric mixture contains ... combustion takes place.
a. a surplus of fuel so that incomplete
b. a surplus of nitrogen so that no
c. a surplus of oxygen so that complete
d. just enough fuel so that complete
, 14. A flow divider in a combustion chamber is used to:
a. drain the fuel when only a small mass flow is required
b. drain the fuel when the engine is turned off
c. ensure a stable output pressure of the atomizer
d. not let the mass flow rate fluctuate too much
15.
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
a. I is right, II is right
b. I is right, II is wrong
c. I is wrong, II is right
d. I is wrong, II is wrong
16. What line represents the fastest deceleration from Y to X ?
a. A
b. B
c. C
d. D
17. A fuel metering graph is given at sea level:
