Gas Turbines online quiz on “Inlet and Compressor Casing”.
1. Capacity of rotary screw compressor is _______ by using unloader.
a) constant
b) varied
c) unloader is not used for compressing
d) none of the mentioned
Answer: a
Clarification: Capacity of rotary screw compressor can be varied by using unloader. When unloader is completely opened its capacity gets decreased to the minimum.
2. Amount of air that can be sucked in by compressor is regulated by using ___________
a) check valve
b) feed valve
c) unloader
d) none of the mentioned
Answer: c
Clarification: Amount of air that can be sucked in can be regulated using unloader. When unloader is completely opened compressor totally minimizes the air entering the compressor.
3. Unloader is also called as intake valve.
a) True
b) False
Answer: b
Clarification: Intake valve is used to regulate the flow capacity where as unloader is used to vary the load.
4. Unloader closes 100% of the air intake.
a) True
b) False
Answer: b
Clarification: Unloader closes the intake to the maximum extent but 100% cannot be closed.
5. When unloader is closed it uses _________ work.
a) 30%
b) 50%
c) 20%
d) 40%
Answer: a
Clarification: When unloader is closed it used 30% work. For unloader to close it needs to apply some pressure which is applied in the form of work.
6. ___________ unloader are used in stationary compressors.
a) Continuous
b) Variable
c) Continuous & Variable
d) None of the mentioned
Answer: a
Clarification: Stationary compressors use continuous unloader. In stationary compressors inlet air should be frequently controlled for proper working and hence continuous unloaders are used.
7. Continuous unloader is used in _________ engine compressor.
a) diesel
b) gasoline
c) dual
d) none of the mentioned
Answer: a
Clarification: Continuous unloader is used in diesel engine compressor. In diesel engine the amount of fuel intake is to be controlled regularly.
8. When choke points are joined in graph representing speeds it is called as ________
a) temperature line
b) choke line
c) critical line
d) none of the mentioned
Answer: b
Clarification: When choke points are joined in graph representing speeds it is called as choke lines. Choke points are the points at which the turbine starts choking at that particular speed and fuel intake.
9. When compressor operates at ________ choking takes place.
a) high mass
b) low mass
c) high temperature
d) none of the mentioned
Answer: a
Clarification: When compressor operates at high mass choking takes place. When mass increases its inlet quantity increases and hence turbine starts to choke.
10. Choking occurs when mach number reaches ________
a) 3
b) 2
c) 1
d) 4
Answer: c
Clarification: When mach number reaches unity no more mass can be reached and hence choking takes place. When mach number reaches unity its speed is heavily increased and hence mass flow is also increased to a great extent.
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