Test
Turbine Engine Compressors
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Preguntas del test (32)
1What is the configuration/description of a centrifugal compressor?
- AShort in length, spoke-like design, easy to manufacture, with high compression per stage.
- BLong in length, spoke-like design, easy to manufacture, with moderate compression per stage.
- CLong in length, spoke-like design, easy to manufacture, with high compression per stage.
- DShort in length, spoke-like design, easy to manufacture, with moderate compression per stage.
2What are the advantages of a centrifugal compressor over an axial flow compressor?
- ACheaper and easier to manufacture, more robust, better handling of FOD ingestion, less prone to stalling and surging, relatively lower in weight.
- BCheaper and easier to manufacture, more robust, better handling of FOD ingestion, less prone to stalling and surging, relatively higher in weight.
- CCheaper and easier to manufacture, more robust, better handling of FOD ingestion, more prone to stalling and surging, relatively lower in weight.
- DCheaper and harder to manufacture, more robust, better handling of FOD ingestion, less prone to stalling and surging, relatively lower in weight.
3What is an impellor?
- AThe internal rotating component of a centrifugal compressor, which takes inlet/intake air at its centre and compresses it by centrifugal force. Sometimes known as the rotor.
- BThe internal rotating component of a axial compressor, which takes inlet/intake air at its centre and compresses it by centrifugal force. Sometimes known as the rotor.
- CThe internal rotating component of a axial compressor, which takes inlet/intake air and compresses it by centrifugal force. Sometimes known as the rotor.
- DThe internal rotating component of a centrifugal compressor, which takes inlet/intake air and compresses it by centrifugal force. Sometimes known as the rotor.
4What is the purpose of the diffuser?
- ATo decrease the airs velocity and increase its pressure
- BTo decrease the airs velocity and decrease its pressure
- CTo increase the airs velocity and increase its pressure
- DTo increase the airs velocity and decrease its pressure
5Where does the air pressure increase as it passes through centrifugal compressor?
- AAir pressure increases progressively through the impeller and increases rapidly through the diffuser
- BAir pressure decreases progressively through the impeller and increases rapidly through the diffuser
- CAir pressure increases rapidly through the impeller and increases progressively through the diffuser
- DAir pressure increases rapidly through the impeller and increases rapidly through the diffuser
6How does the velocity and pressure vary through a centrifugal compressor?
- AVelocity and pressure both increase through the impeller, however through the diffuser the velocity decreases and pressure increases
- BVelocity and pressure both decrease through the impeller, however through the diffuser the velocity decreases and pressure increases
- CVelocity and pressure both decrease through the impeller, however through the diffuser the velocity increases and pressure increases
- DVelocity and pressure both increase through the impeller, however through the diffuser the velocity increases and pressure increases
7What is the configuration/description of an axial flow compressor?
- AMultiple stages of rotating aerofoil blades and fixed vanes (stators), with a large mass flow capacity and high efficiency.
- BMultiple stages of rotating aerofoil blades and fixed vanes (stators), with a large mass flow capacity and high thrust
- CMultiple stages of rotating aerofoil blades and moving vanes (stators), with a large mass flow capacity and high thrust
- DMultiple stages of rotating aerofoil blades and moving vanes (stators), with a large mass flow capacity and high efficiency.
8What are the advantages of an axial flow compressor over a centrifugal compressor of the same frontal diameter?
- AHigher compressor pressure ratios and greater mass airflow
- BHigher compressor airflow ratios and greater mass airflow
- CHigher compressor speeds and greater mass airflow
- DHigher compressor speeds and greater fuel capacity
9What are the advantages of an axial flow compressor over a centrifugal compressor?
- AA lower frontal area for a given mass airflow, which allows for a smaller diameter engine, achieves higher compression ratios more efficiently, lower pressure rise per stage, a much lower airflow exit velocity compared to its inlet velocity
- BA higher frontal area for a given mass airflow, which allows for a smaller diameter engine, achieves higher compression ratios more efficiently, lower pressure rise per stage, a much lower airflow exit velocity compared to its inlet velocity
- CA higher frontal area for a given mass airflow, which allows for a smaller diameter engine, achieves higher compression ratios more efficiently, higher pressure rise per stage, a much lower airflow exit velocity compared to its inlet velocity
- DA lower frontal area for a given mass airflow, which allows for a smaller diameter engine, achieves higher compression ratios more efficiently, higher pressure rise per stage, a much lower airflow exit velocity compared to its inlet velocity
10What is the definition of the compressor pressure ratio?
- AThe ratio of the compressor outlet pressure to the compressor inlet pressure
- BThe ratio of the compressor outlet pressure to the compressor inlet temperature
- CThe ratio of the compressor outlet velocity to the compressor inlet velocity
- DThe ratio of the compressor outlet velocity to the compressor inlet temperature
11What is the typical total compressor ratio of a single stage centrifugal compressor?
- AUp to about 7.5:1
- BUp to about 15:1
- CUp to about 20:1
- DUp to about 30:1
12What is the typical total compressor ratio of a double stage centrifugal compressor?
- AUp to about 15:1
- BUp to about 7.5:1
- CUp to about 20:1
- DUp to about 3:1
13What is the typical total pressure ratio of a modern axial flow compressor?
- A20:1, but up to 30:1 in come cases
- B10:1, but up to 20:1 in come cases
- C10:1, but up to 30:1 in come cases
- D15:1, but up to 20:1 in come cases
14How does the temperature, pressure and velocity of the air change as it passes through each stage of an axial flow compressor?
- ATemperature and pressure progressively increase and the axial velocity increases across the rotors and decreases across the stators, but overall velocity decreases considering the effect of the diffuser
- BTemperature and pressure progressively increase and the axial velocity decreases across the rotors and decreases across the stators, but overall velocity decreases considering the effect of the diffuser
- CTemperature and pressure progressively increase and the axial velocity decreases across the rotors and increases across the stators, but overall velocity decreases considering the effect of the diffuser
- DTemperature and pressure progressively increase and the axial velocity increases across the rotors and increases across the stators, but overall velocity decreases considering the effect of the diffuser
15What is the function of inlet guide vanes?
- AThe inlet guide vanes are designed to direct the airflow onto the first stage rotors at an appropriate angle of attack.
- BThe inlet guide vanes are designed to direct the airflow onto the last stage rotors at an appropriate angle of attack.
- CThe inlet guide vanes are designed to direct the airflow onto the last stage rotors at an high angle of attack.
- DThe inlet guide vanes are designed to direct the airflow onto the first stage rotors at an high angle of attack.
16What is the function of the variable inlet guide vanes?
- ATo change angle depending on flow characteristics, directing the airflow onto the first stage rotors at the optimal angle of attack, thereby reducing the chance of a compressor stall during operation off design (at low) rpm.
- BTo change angle depending on pressure characteristics, directing the airflow onto the first stage rotors at the optimal angle of attack, thereby reducing the chance of a compressor stall during operation off design (at low) rpm.
- CTo change angle depending on pressure characteristics, directing the airflow onto the first stage rotors at the optimal angle of attack, thereby reducing the chance of a compressor stall during operation off design (at high) rpm.
- DTo change angle depending on flow characteristics, directing the airflow onto the first stage rotors at the optimal angle of attack, thereby reducing the chance of a compressor stall during operation off design (at high) rpm.
17What is the function of the variable stators in an axial flow compressor?
- AThe variable stators are designed to direct the airflow onto the subsequent stage of rotors at the optimum angle of attack, thereby increasing the compressor pressure ratio.
- BThe variable stators are designed to direct the airflow onto the first stage of rotors at the optimum angle of attack, thereby increasing the compressor pressure ratio.
- CThe variable stators are designed to direct the airflow onto the first stage of rotors at the optimum angle of attack, thereby increasing the overall thrust
- DThe variable stators are designed to direct the airflow onto the subsequent stage of rotors at the optimum angle of attack, thereby increasing the overall thrust
18What is the primary function of each row of stator blades?
- ATo convert the kinetic energy of the airflow into pressure energy
- BTo convert the kinetic energy of the airflow into dynamic energy
- CTo convert the dynamic energy of the airflow into kinetic energy
- DTo convert the dynamic energy of the airflow into pressure energy
19What is the secondary function of the stator blades?
- ATo stop swirl in the air thereby maintaining axial flow as it passes through the compressor
- BTo stop swirl in the air thereby maintaining centrifugal flow as it passes through the compressor
- CTo allow swirl in the air thereby maintaining centrifugal flow as it passes through the compressor
- DTo allow swirl in the air thereby maintaining axial flow as it passes through the compressor
20What are the function of the rotors and stators in an axial flow compressor?
- AThe rotors accelerate the airflow and the stators decelerate the flow to increase the airs pressure
- BThe rotors decelerate the airflow and the stators decelerate the flow to increase the airs pressure
- CThe rotors dedcelerate the airflow and the stators accelerate the flow to increase the airs pressure
- DThe rotors accelerate the airflow and the stators accelerate the flow to increase the airs pressure
21What shape does an axial flow compressor form towards the combustion chamber?
- AA converging duct
- BA diverging duct
- CA straight duct
22Why does the air annulus area decrease towards the high pressure end of an axial flow compressor?
- ATo allow for the reduction in the volume of air as its pressure progressively increases and to maintain the axial velocity of the air constant as the density increases
- BTo allow for the increase in the volume of air as its pressure progressively increases and to maintain the axial velocity of the air constant as the density decreases
- CTo allow for the increase in the volume of air as its pressure progressively increases and to maintain the axial velocity of the air constant as the density increases
- DTo allow for the reduction in the volume of air as its pressure progressively increases and to maintain the axial velocity of the air constant as the density decreases
23Why is there only a small pressure increase across each stage of an axial flow compressor?
- ABecause the aerofoil blades are, by necessity, quite small and consequently only produce a small amount of lift at each stage
- BBecause the aerofoil blades are, by necessity, quite large and consequently only produce a small amount of lift at each stage
- CBecause the aerofoil blades are, by necessity, quite large and consequently only produce a small amount of thrust at each stage
- DBecause the aerofoil blades are, by necessity, quite small and consequently only produce a small amount of thrust at each stage
24What is a likely result from unstable airflow through a compressor?
- AA compressor stall.
- BA turbine stall.
- CAn engine mafunction
- DA partial loss of power
25What determines the angle of attack of a compressor blade at a given blade angle at any given time?
- AThe RPM of the compressor an the TAS of the airflow
- BThe angle of the airflow from the previous location
- CThe smoothness of the air entering
- DThe RPM of the turbine and the TAS of the airflow
26What is the condition that leads to compressor stalls?
- AThe axial velocity of the airflow is too low relative to the RPM.
- BThe axial pressure of the airflow is too low relative to the RPM.
- CThe axial temperature of the airflow is too low relative to the RPM.
- DThe axial density of the airflow is too low relative to the RPM.
27What is the principle effect/purpose of the bleed valves/bands in the compressor?
- ATo offload the compressor (LP and HP) and increase the mass airflow through the early stages of the compressor, during acceleration from low engine speed thereby reducing the possibility of compressor stall and surge at low rpm.
- BTo offload the compressor (LP and HP) and reduce the mass airflow through the early stages of the compressor, during acceleration from low engine speed thereby reducing the possibility of compressor stall and surge at low rpm.
- CTo offload the compressor (LP and HP) and reduce the mass airflow through the early stages of the compressor, during acceleration from low engine speed thereby negating the possibility of compressor stall and surge at low rpm.
- DTo offload the compressor (LP and HP) and increase the mass airflow through the early stages of the compressor, during acceleration from low engine speed thereby negating the possibility of compressor stall and surge at low rpm.
28What positions are the surge/stall bleed valves or bleed bands during engine acceleration?
- AOpen at low and increasing rpm, progressively closing as rpm increases to design rpm
- BClosed at low and increasing rpm, progressively opening as rpm increases to design rpm
- CClosed at high and increasing rpm, progressively opening as rpm increases to design rpm
- DOpen at high and increasing rpm, progressively closing as rpm increases to design rpm
29Do turbine engines use the same compressor bleed outlets for surge/stall protections as they do for environmental control systems?
- ANo
- BYes
30What is the normal source of bleed air at high and moderate (climb and cruise) power settings?
- AThe low pressure compressor
- BThe high pressure compressor
- CThe intermediate pressure compressor
- DBoth the low and high pressure compressors in a two spool engine,, and all three of the low, intermediate and high pressure compressors in a three spool engine.
31What is the normal source of bleed air at low (descent) power settings?
- ABoth the low and high pressure compressors in a two spool engine,, and all three of the low, intermediate and high pressure compressors in a three spool engine.
- BThe low pressure compressor
- CThe high pressure compressor
- DThe intermediate pressure compressor
32What are the effects of bleeding air off the compressor for systems such as anti-icing?
- AGas temperature increases, thrust reduces and SFC increases.
- BGas temperature reduces, thrust reduces and SFC increases.
- CGas temperature reduces, thrust reduces and SFC reduces.
- DGas temperature increases, thrust reduces and SFC reduces.
Información
- Descripción
- Turbine Engine Compressors
- Autor
- Andrew Lee
- Idioma
- English
- Visitas
- 69
- Etiquetas
- Valoración
- Aún sin valoraciones Valora este test