3B2 Power Engineer exam practice questions and
answers with solutions
The disadvantages of a gas turbine are:
1. High cost of manufacture
2. High levels of noise pollution are produced
3. Low thermal efficiency
4. Requires many auxiliaries to be efficient
A. 1, 2, 3
B. 1, 3, 4
C. 2, 3, 4
D. 1, 2, 4
E. 1, 2, 3, 4 - ANSWER E
The most common process method of refrigeration is:
Select one:
A. Absorption
B. Lithium bromide
C. Water vapor
D. Vapor compression or mechanical
,E. Ammonia compression system - ANSWER D
To facilitate the removal of moisture and oil from the compressed air,
a/an _____ is installed.
Select one:
A. Intercooler
B. Oil separator
C. Unloader
D. Expansion tank
E. Aftercooler - ANSWER E
In a two-stage refrigeration system, the 1st stage compressor is also
known as a _____ compressor.
Select one:
A. Booster
B. Standby
C. Low volume
D. Extraction
E. Refrigerant - ANSWER A
In the rotary vane compressor:
Select one:
A. Vanes close to the central hub by centrifugal force
B. There is a rotor in the exact center of the casing
,C. Refrigerant is trapped between the roller and the decreasing volume
of the eccentric casing
D. The rotor oscillates
E. The vanes move in the rotor - ANSWER E
In a gas turbine, there are fewer turbine stages than compressor stages
because:
Select one:
A. Energy can be extracted more efficiently in the turbine
B. Turbine blades are bigger so require fewer
C. Higher exhaust temperatures can be tolerated
D. The hot gases occupy more volume
E. Hot exhaust gases are required for the HRSG's - ANSWER A
Pressure limiting devices of refrigeration systems shall be connected:
Select one:
A. Between the compressor and the stop valve on the suction side
B. To a blowdown tank
C. Between the inlet of the condenser and the outlet of the receiver
D. Between the compressor and the stop valve on the discharge side
E. To the receiver outlet - ANSWER D
The warm-up time required of a turbine is dependant on:
Select one:
, A. How quickly the turbine is required
B. The manufacturer's instructions
C. The size of the turbine
D. The type of turbine
E. Whether the steam is dry or wet - ANSWER C
_____ compressors require intake and discharge valves.
Select one:
A. Rotary
B. Centrifugal
C. Sliding vane
D. Rotary lobe
E. Reciprocating - ANSWER E
Besides reducing NOx, water injection systems
Select one:
a. stabilize the combustion process, thereby increasing the life of hot
section components
b. help keep the compressor blading clean
c. reduce the gas turbine's thermal efficiency
d. decrease the power output - ANSWER C
The pressure at the outlet from the moving blades is the same as the
pressure at the inlet to the moving blades in a/an __________ turbine.
answers with solutions
The disadvantages of a gas turbine are:
1. High cost of manufacture
2. High levels of noise pollution are produced
3. Low thermal efficiency
4. Requires many auxiliaries to be efficient
A. 1, 2, 3
B. 1, 3, 4
C. 2, 3, 4
D. 1, 2, 4
E. 1, 2, 3, 4 - ANSWER E
The most common process method of refrigeration is:
Select one:
A. Absorption
B. Lithium bromide
C. Water vapor
D. Vapor compression or mechanical
,E. Ammonia compression system - ANSWER D
To facilitate the removal of moisture and oil from the compressed air,
a/an _____ is installed.
Select one:
A. Intercooler
B. Oil separator
C. Unloader
D. Expansion tank
E. Aftercooler - ANSWER E
In a two-stage refrigeration system, the 1st stage compressor is also
known as a _____ compressor.
Select one:
A. Booster
B. Standby
C. Low volume
D. Extraction
E. Refrigerant - ANSWER A
In the rotary vane compressor:
Select one:
A. Vanes close to the central hub by centrifugal force
B. There is a rotor in the exact center of the casing
,C. Refrigerant is trapped between the roller and the decreasing volume
of the eccentric casing
D. The rotor oscillates
E. The vanes move in the rotor - ANSWER E
In a gas turbine, there are fewer turbine stages than compressor stages
because:
Select one:
A. Energy can be extracted more efficiently in the turbine
B. Turbine blades are bigger so require fewer
C. Higher exhaust temperatures can be tolerated
D. The hot gases occupy more volume
E. Hot exhaust gases are required for the HRSG's - ANSWER A
Pressure limiting devices of refrigeration systems shall be connected:
Select one:
A. Between the compressor and the stop valve on the suction side
B. To a blowdown tank
C. Between the inlet of the condenser and the outlet of the receiver
D. Between the compressor and the stop valve on the discharge side
E. To the receiver outlet - ANSWER D
The warm-up time required of a turbine is dependant on:
Select one:
, A. How quickly the turbine is required
B. The manufacturer's instructions
C. The size of the turbine
D. The type of turbine
E. Whether the steam is dry or wet - ANSWER C
_____ compressors require intake and discharge valves.
Select one:
A. Rotary
B. Centrifugal
C. Sliding vane
D. Rotary lobe
E. Reciprocating - ANSWER E
Besides reducing NOx, water injection systems
Select one:
a. stabilize the combustion process, thereby increasing the life of hot
section components
b. help keep the compressor blading clean
c. reduce the gas turbine's thermal efficiency
d. decrease the power output - ANSWER C
The pressure at the outlet from the moving blades is the same as the
pressure at the inlet to the moving blades in a/an __________ turbine.
