Top 150+ Solved Thermal Engineering 1 MCQ Questions Answer
Q. Volumetric efficiency is
a. the ratio of stroke volume to clearance volume
b. the ratio of the air actually delivered to the amount of piston displacement
c. reciprocal of compression ratio
d. index of compressor performance
Q. Volumetric efficiency of a compressor with clearance volume
a. increases with increase in compression ratio
b. decreases with increase in compression ratio
c. is not dependent upon compression ratio
d. may increase/decrease depending on compressor capacity
Q. Volumetric efficiency of a compressor without clearance volume
a. increases with increase in compression ratio
b. decreases with increase in compression ratio
c. is not dependent upon compression ratio
d. may increase/decrease depending on compressor capacity
Q. The clearance volume of the air compressor is kept minimum because
a. it allows maximum compression to be achieved
b. it greatly affects volumetric efficiency
c. it results in minimum work
d. it permits isothermal compression
Q. Which is false statement about multistage compression.
a. Power consumption per unit of air delivered is low
b. Volumetric efficiency is high
c. It is best suited for compression ratios around 7:1
d. The moisture in air is condensed in the intercooler
Q. Reciprocating air compressor is best suited for
a. large quantity of air at high pressure
b. small quantity of air at high pressure
c. small quantity of air at low pressure
d. large quantity of air at low pressure
Q. Rotary compressor is best suited for
a. large quantity of air at high pressure
b. small quantity of air at high pressure
c. small quantity of air at low pressure
d. large quantity of air at low pressure
Q. After-cooler is used to
a. cool the air
b. decrease the delivery temperature for ease in handling
c. cause moisture and oil vapour to drop out
d. reduce volume
Q. The compressor performance at higher altitude compared to sea level will be
a. same
b. higher
c. lower
d. dependent on other factors
Q. Pick up the wrong statement about advantages of multistage compression
a. better lubrication is possible advantages of multistage
b. more loss of air due to leakage past the cylinder
c. mechanical balance is better
d. air can be cooled perfectly in between
Q. Losses in a centrifugal compressor are due to
a. inlet losses
b. impeller channel losses
c. diffuser losses
d. all of the above
Q. For supplying intermittent small quantity of air at high pressure, following compressor is best suited
a. centrifugal
b. reciprocating
c. axial
d. screw
Q. For minimum work in multistage compression, assuming same index of compression in all stages
a. work done in first stage should be more
b. work done in subsequent stages should increase
c. work done in subsequent stages should decrease
d. work done in all stages should be equal
Q. Diffuser in a compressor is used to
a. increase velocity
b. make the flow stream-line
c. convert pressure energy into kinetic energy
d. convert kinetic energy into pressure energy
Q. Phenomenon of choking in compressor means
a. no flow of air
b. fixed mass flow rate regardless of pressure ratio
c. reducing mass flow rate with increase in pressure ratio
d. increased inclination of chord with air steam