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
(D) proportional to compression ratio
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 compressin ratio
(D) may increase/decrease depending on compressor capacity
(D) unpredictable
Volumetric efficiency of air compressors is of the order of________________?
(A) 20-30%
(B) 40-50%
(C) 60-70%
(D) 70-90%
(D) 90-100%
Cylinder clearance in a compressor should be _________________?
(A) as large as possible
(B) as small as possible
(C) about 50% of swept volume
(D) about 100% of swept volume
(D) none of the above
Ratio of indicated H.P. and brake H.P. is known as_________________?
(A) mechanical efficiency
(B) volumetric efficiency
(C) isothermal efficiency
(D) adiabatic efficiency
(D) relative efficiency
Aeroplanes employ following type of compressor_______________?
(A) radial flow
(B) axial flow
(C) centrifugal
(D) combination of above
(D) none of the above
Compression efficiency is compared against_____________________?
(A) ideal compression
(B) adiabatic compression
(C) botii isothermal and adiabatic compression
(D) isentropic compression
(D) isothermal compression
An ideal air compressor cycle with clearance on p-v diagram can be represented by following processes_______________?
(A) one adiabatic, two isobaric, and one constant volume
(B) two adiabatic and two isobaric
(C) two adiabatic, one isobaric and one constant volume,
(D) one adiabatic, one isobaric and two constant volume
(D) two isobaric, two adiabatic and one constant volume
The work done per unit mass of air in compression will’be least when n is equal to______________?
(A) 1
(B) 1.2 ,
(C) 1.3
(D) 1.4
(D) 1.5
Which is false statement about air receivers ___________________?
(A) These are used to dampen pulsations ,
(B) These act as reservoir to- take care of sudden demands
(C) These increase compressor efficiency
(D) These knock out some oil and moisture
(D) These reduce frequent on/off operation of compressors