compressors gas turbines and jet engines MCQs

B. adiabatic compression

C. isentropic compression

D. botii isothermal and adiabatic compression

E. ideal compression

B. relief valve

C. start-stop motor

D. variable speed

E. none of the above

A. from any one of the above locations

B. from coal yard side

C. from outside atmosphere at 1C

D. from an air conditioned room maintained at 20C

A. may increase/decrease depending on clearance volume

B. increase

C. remain same

E. none of the above

A. to attain high volumetric efficiency

C. to avoid mechanical bang of piston with cylinder head

D. to provide cushioning effect

E. to accommedate Valves in the cylinder head

A. remain same

B. decrease

C. unpredictable

D. none of the above

A. air stream blocking the passage

C. air stream not able to follow the blade contour

D. production of no air pressure

E. motion of air at sonic velocity

A. may be less or more depening upon speed

C. same

D. none of the above

E. more

A. high friction losses

C. high pressure ratio

D. high specific volume

E. increasing gas temperature

A. minimum cycle temperature

B. maximum cycle temperature

C. none of the above

D. all of the above

A. resultant component

B. tangential component

D. radial component

A. none of the above

C. centrifugal pump

D. reciprocating pump

E. sliding vane compressor

A. passing steam over incandescent coke

B. passing air and a large amount of steam over waste coal at about 65C

C. carbonisation of coal

D. same way as the natural gas

A. high h.p. and low weight

B. high speed and high h.p.

C. small frontal area and high h.p.

D. all of the above

A. decrease of heat loss in exhaust

B. none of the above

D. high thermal efficiency

E. reduction in compressor work

A. to save fuel

C. to increase the efficiency

D. to increase the output

E. none of the above

B. using mulit-stage compressor with mfercooler

C. adding heat exchanger

D. reheating the air after partial expansion in the turbine

E. injecting water in/around combustion chamber

A. lost work

B. increasing speed of incoming air

C. compression of inlet air

D. leakage losses

B. none of the above

C. more/less power depending on other factors

D. same power

E. more power

A. none of the above

C. poppet valve

D. mechanical valve of the corliss, sleeve, rotary or semirotary type

E. any of the above

A. large gas turbines use radial inflow turbines

B. gas turbines have their blades similar to steam turbine

D. gas turbines use both air and liquid cooling

E. all of the above are correct.

A. 30:01:00

B. 15:01

C. 7:01

D. 40:01:00

A. 25C, 1 kg/cm2 and relative humidity of 50%.

B. 20C and 1 kg/cm2 and relative humidity of 36%

C. 15C and 1 kg/cm2

E. 0C and standard atmospheric conditions

A. gas turbine can be easily started and stopped and thus is best suited for peaking demands

B. exhaust losses in gas turbine are high due to large mass flow rate

D. gas turbine does not require huge quantity of water like steam plant

E. overall efficiency of gas turbine plant is lower than that of a reciprocating engine

A. none of the above

B. it permits isothermal compression

D. it allows maximum compression to be achieved

E. it results in minimum work

A. 10%.

B. 0.50%

C. 5%

E. 0.10%

A. high alloy seel

B. mild steel

C. carbon steel

E. stainless steel

B. 1:01

C. 1:05

D. 1:10

E. 1:02

A. increase of work ratio

B. decrease of thermal efficiency

C. decrease of work ratio

E. both B. and C. above

A. stainless steel

B. titanium

D. duralumin

E. high alloy steel

A. varies as square root of the speed

B. Varies linearly to the speed

D. varies as cube of the speed

E. is constant irrespective of variation in speed

A. 16 kg/cm2

B. 25 kg/cm2

D. 40 kg/cm2

E. 6 kg/cm2

A. total temperature drop

B. total adiabaitc temperature drop

C. adiabatic temperature drop in the stage

D. difference of maximum and minimum temperature in the cycle

A. large quantity of air at high pressure

B. any one of the above

C. small quantity of air at low pressure

D. large quantity of air at low pressure

A. highest

B. none of the above

C. anything.

E. lowest

A. equal to zero

C. opposite to the direction of motion of blades

D. depending on the velocity

E. none of the above

A. work done is maximum

B. entropy decreases

D. temperature rise follows a linear relationship

E. temperature during compression remains constant

A. isochronically

B. adiabatically

C. as per law pV

E. isentropically

A. isothermal work to ideal work

B. work to compress air isothermally to work for actual compression

C. power to drive compressor to isothermal h.p.

E. isothermal h.p. to adiabatic h.p.

A. net work output and heat supplied

B. actual/heat drop and isentropic heat drop

C. work done by turbine and net work output

D. work done by turbine and heat supplied

B. gas turbine uses same working fluid over and over again

C. closed cycle gas turbine is an I.C engine

D. ideal efficiency of closed cycle gas turbine plant is more than carnot cycle efficiency

E. air-fuel ratio in a gas turbine is 100 : 1

A. work coefficient

B. compressor efficiency

D. polytropic reaction

E. slip factor

A. same

B. none of the above

C. dependent on other factors

E. higher

B. decreases

C. remains same

D. first decreases and then increases

E. first increases and then decreases

A. compressor work and turbine work

B. actual compressor work and theoretical comprssor work

D. output and input

E. none of the above

A. large quantity of air at low pressure

B. small quantity of air at low pressure

C. small quantity of air at high pressure

D. any one of the above

A. after receiver

B. before suction

C. before intercooler

D. after intercooler

A. inversely proportional to clearance volume

B. directly proportional to clearance volume

D. greatly affected by clearance volume

B. compressor effectiveness

C. compression index

D. compressor efficiency

E. compression ratio

B. any one of the above

C. isothermal

D. polytropic

E. none of the above