Turbo Machines 3

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Turbo Machines 3

Part 3: List for questions and answers of Turbo Machines

Q1.The flow on two sides of a normal shock wave is
a) Subsonic
b) Sonic
c) Supersonic
d) Supersonic on one side and subsonic on the other side

Q2.The diverging portion of the nozzle acts as a diffuser for
a) The subsonic flow
b) The supersonic flow
c) Both the subsonic as well as supersonic flow
d) None of the above

Q3.A diffuser
a) Converts kinetic energy into thermal energy
b) Converts potential energy into kinetic energy
c) Converts pressure energy into kinetic energy
d) Converts thermal energy into kinetic energy

Q4.Brayton cycle cannot be used in reciprocating engines even for same compression ratio and work output because
a) Otto cycle is more efficient
b) Brayton cycle is less efficient
c) Brayton cycle is for slow speed engines only
d) Large volume of low pressure gas cannot be efficiently handled in reciprocating
engines

Q5.Actual gas turbine cycle is different from ideal cycle because
a) Of internal irreversibility of the process due to friction, turbulence, etc
b) Of variation of specific heats with temperature
c) Of losses due to incomplete combustion
d) All of the above

Q6.The advantage of a gas turbine over a reciprocating engine is
a) Perfect balancing of rotor
b) Continuous and uniform power
c) Usually small working pressures
d) All of the above

Q7.Overall efficiency of a gas turbine is
a) Equal to Rankine cycle efficiency
b) Equal to Carnot cycle efficiency
c) Less than Diesel cycle efficiency
d) More than Otto or Diesel cycle efficiency

Q8.Air fuel ratio for a gas turbine is closer to
a) 10 ; 1
b) 15 ; 1
c) 20 ; 1
d) 60 ; 1

Q9.Which of the following is a positive displacement rotory compressor?
a) Roots blower
b) Centrifugal compressor
c) Axial flow compressor
d) All of the above

Q10.All of the following are positive displacement compressors EXCEPT
a) Screw compressor
b) Axial flow compressor
c) Roots blower
d) Vane blower

Q11.For efficient operation of axial flow compressors the blades are made
a) Straight
b) Slightly curved
c) Aerofoil section
d) Forward curved

Q12.Thermal efficiency of a gas turbine is in the range
a) 50 to 60 percent
b) 40 to 50 percent
c) 30 to 40 percent
d) 20 to 30 percent

Q13.The efficiency of a simple open cycle gas turbine depends upon
a) Pressure ratio
b) Compressor efficiency
c) Turbine inlet temperature
d) All of the above

Q14.Which of the following steam turbine has identical fixed and moving blades?
a) Curtis turbine
b) Rateau turbine
c) Parson’s turbine
d) None of the above

Q15.Which of the following is a pressure compounded turbine?
a) Parson’s turbine
b) Curtis turbine
c) Rateau turbine
d) All of the above

Q16.The continuity equation in compressible fluids is derived on the basis of
a) Conservation of momentum
b) Conservation of energy
c) Conservation of mass
d) Conservation of velocity head

Q17.As there is plenty of time for heat transfer across the walls, the flow in long pipes at low velocities attains
a) Isentropic conditions
b) Adiabatic conditions
c) Isothermal conditions
d) Polytropic conditions

Q18.In a hot wire anemometer the rate of heat loss from sensing element is a function of
a) Pressure
b) Mass rate of flow
c) Velocity of flow
d) None of the above

Q19.The normal shock wave in compressible flow is analogous to
a) Surges in open channel
b) Vortex formation in centrifugal pump
c) Hydraulic bore in tidal rivers
d) Hydraulic jump in channel flow

Q20.A roots blower compresses 0.06 cubic metres of air from 1.0 bar to 1.45 bar per revolution. The compressor efficiency is nearly
a) 99%
b) 87%
c) 75%
d) 63%

Part 3: List for questions and answers of Turbo Machines

Q1. Answer: d

Q2. Answer: a

Q3. Answer: a

Q4. Answer: d

Q5. Answer: d

Q6. Answer: d

Q7. Answer: c

Q8. Answer: d

Q9. Answer: a

Q10. Answer: b

Q11. Answer: c

Q12. Answer: c

Q13. Answer: d

Q14. Answer: c

Q15. Answer: c

Q16. Answer: c

Q17. Answer: c

Q18. Answer: c

Q19. Answer: d

Q20. Answer: b