Applied Thermodynamics (3161910) MCQs

MCQs of Part-I Reciprocating Compressors

Showing 51 to 60 out of 66 Questions
51.

The multi-stage compression of air as compared to single-stage compression

(a)

improves volumetric efficiency for the given pressure ratio

(b)

reduces workdone per kg of air

(c)

gives more uniform torque

(d)

all of these

Answer:

Option (d)

52.

The advantage of multistage compression over single-stage compression is

(a)

lower power consumption per unit of air delivered

(b)

higher volumetric efficiency

(c)

decreased discharge temperature

(d)

all of the above

Answer:

Option (d)

53.

When air is to be compressed at high pressure, then it is advantageous to use

(a)

single-stage compression

(b)

multi-stage compression without intercooling

(c)

multi-stage compression with intercooling

(d)

none of these

Answer:

Option (c)

54.

An aftercooler is used to

(a)

remove impurities from air

(b)

reduce volume of air

(c)

cause moisture and oil vapour to drop out

(d)

cool the air

Answer:

Option (c)

55.

When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is __________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling.

(a)

equal to

(b)

less than

(c)

more than

(d)

all of the mentioned

Answer:

Option (a)

56.

The intercooler pressure, for minimum work required, for a two-stage reciprocating air compressor, is given by (where p1 = Intake pressure of air, p2 = Intercooler pressure, and p3 = Delivery pressure of air)

(a)

p2=p1p3 

(b)

p2=p1p3

(c)

p2=p1×p3

(d)

p2=p3p1

Answer:

Option (a)

57.

Maximum work is saved in a two stage reciprocating air compressor with

(a)

incomplete intercooling

(b)

complete intercooling

(c)

no intercooling

(d)

after cooling

Answer:

Option (b)

58.

For perfect intercooling in a two stage compressor

(a)

p2p1=p3p2

(b)

p1p3=p2p1

(c)

p1=p3

(d)

p1=p2p3

Answer:

Option (a)

59.

In a four stage compressor, if the pressure at the first and third stage are 1 bar and 16 bar, then the delivery pressure at the fourth stage will be

(a)

1 bar

(b)

16 bar

(c)

64 bar

(d)

256 bar

Answer:

Option (c)

60.

For minimum work required to compress and deliver a quantity of air by multi-stage compression

(a)

the compression ratio in each stage should be same

(b)

the intercooling should be perfect

(c)

the workdone in each stage should be same

(d)

all of the above

Answer:

Option (d)

Showing 51 to 60 out of 66 Questions