WorksheetsCompresssor EOAP-2023
Total questions: 25
Worksheet time: 27mins
A compressor increases the ___ of a gas by ___ its ___ .
pressure, reducing, volume
pressure, increasing, volume
pressure, reducing, temperature
pressure, increasing, temperature
Following type is a positive displacement compressor
Screw
Diaphragm
Centrifugal
All of the above
Reciprocating compressors use ___ driven by a ___ .
belt, pulley
chain, sprocket
pistons, crankshaft
any of the above
Reciprocating compressors suffer higher losses due to
clearance volumes
resistance due to discharge and suction valves
more weight
all of the above
A diffuser section in Centrifugal compressor coverts velocity energy to
mechanical energy
heat energy
pressure energy
potential energy
A centrifugal compressor works on the principle of
conversion of pressure energy into kinetic energy
conversion of kinetic energy into pres¬sure energy
centripetal action
generating pressure directly
combination of (a) and (d).
Actual compression curve is
same as isothermal
same as adiabatic
better than isothermal and adiabatic
in between isothermal and adiabatic
none of the above.
Adiabatic compression is one in which
emperature during compression remains constant
no heat leaves or enters the compressor cylinder during cornpression
temperature rise follows a linear relationship
work done is maximum
entropy decreases.
After-cooler is used to
cool the air
decrease the delivery temperature for ease in handling
cause moisture and oil vapour to drop out
reduce volume
increase pressure.
An ideal air compressor cycle with clearance on p-v diagram can be represented by following processes
one adiabatic, two isobaric, and one constant volume
two adiabatic and two isobaric
two adiabatic, one isobaric and one constant volume,
one adiabatic, one isobaric and two constant volume
two isobaric, two adiabatic and one constant volume.
An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes
one adiabatic, two isobaric, and one constant volume
two adiabatic and two isobaric
two adiabatic, one isobaric and one constant volume
one adiabatic, one isobaric and two constant volume
two isobaric, two adiabatic and one constant volume.
Clearance volume in actual reciprocating compressors is essential
to accommedate Valves in the cylinder head
to provide cushioning effect
to attain high volumetric efficiency
to avoid mechanical bang of piston with cylinder head
to provide cushioning effect and also to avoid mechanical bang of piston with cylinder head.
Compression efficiency is compared against
ideal compression
adiabatic compression
botii isothermal and adiabatic compression
isentropic compression
isothermal compression.
Cylinder clearance in a compressor should be
as large as possible
as small as possible
about 50% of swept volume
about 100% of swept volume
none of the above.
Diffuser in a compressor is used to
increase velocity
make the flow stream-line
convert pressure energy into kinetic energy
convert kinetic energy into pressure energy
increase degree of reaction.
During maximum load operation, the best method of controlling compressor is
start-stop motor
constant speed unloader
relief valve
variable speed
none of the above.
In multistage compressor, the isothermal compression is achieved by
employing intercooler
by constantly cooling the cylinder
by running compressor at very slow speed
by insulating the cylinder
none of the above.
Inter cooling in compressors
cools the delivered air
results in saving of power in compressing a given volume to given pressure
is the standard practice for big compressors
enables compression in two stages
prevents compressor jacket running very hot.
Pick up the wrong statement
centrifugal compressors deliver prac-tically constant pressure over a considerable range of capacities
Axial flow compressors have a sub-stantially constant delivery at variable pressures
centrifugal compressors have a wider stable operating range than axial flow compressors
axial flow compressors are bigger in diameter compared to centrifugal type
axial flow compressors apt to be longer as compared to centrifugal type.
Ratio of compression is the ratio of
gauge discharge pressure to the gauge intake pressure
absolute discharge pressure to the ab-solute intake pressure
pressures at discharge and suction cor-responding to same temperature
stroke volume and clearance volume
none of the above.
Reciprocating air compressor is best suited for
large quantity of air at high pressure
small quantity of air at high pressure
small quantity of air at low pressure
large quantity of air at low pressure
any one of the above.
Separators in compressor installations are located
before intercooler
after intercooler
after receiver
between after-cooler and air receiver
before suction.
The advantage of multistage compression over single stage compression is
lower power consumption per unit of air delivered
higher volumetric efficiency
decreased discharge temperature
moisture free air
all of the above.
The clearance volume of the air compressor is kept minimum because
it allows maximum compression to be achieved
it greatly affects volumetric efficiency
it results in minimum work
it permits isothermal compression
none of the above.
The compressor capacity with decrease in suction temperature
increases
decreases
remains unaffected
may increase or decrease depending on compressor capacity
increases upto certain limit and then decreases.
