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This set of Turbo Machines Multiple Choice Questions & Answers (MCQs) focuses on Turbo Machines Set 2
Q1 | In an axial flow compressor, the pressure rise occurs in
- fixed blades only
- Moving blades only
- Both fixed and moving blades
- none of the above
Q2 | Surging is
- an unsteady, periodic and reversal of flow in the compressor
- the fixed mass flow rate regardless of pressure ratio
- the reduction in lift force at higher angles of incidence
- none of the above
Q3 | A regenerator can be used on
- open cycle gas turbines only
- closed cycle gas turbines only
- both open as well as closed cycle gas turbines
- none of the above
Q4 | Maximum delivery pressure in a rotary air compressor is of the order of
- 10 KSC
- 16 KSC
- 6 KSC
- 25 KSC
Q5 | An axial flow compressor has
- smaller blades at gas entry and larger blades at exit
- identical dlades at exit as well as entry
- larger blades at gas entry and smaller blades at exit
- size of blades remains same only angles changes
Q6 | In a gas turbine cycle regenerator is used to
- heat fuel supplied to combustion chamber
- heat air supplied to combustion chamber
- heat the gases coming out of combustion chamber
- heat exhaust gases released from low pressure turbine
Q7 | In a nozzle, once the critical conditions are achieved at the throat, than which of the following remains constant
- Density of fluid
- Velocity of fluid
- Flow rate
- All of the above
Q8 | The range of compression ratio in a gas turbine is
- 3 to 6
- 5 to 8
- 12 to 22
- 8 to 12
Q9 | In a hot wire anemometer the rate of heat loss from sensing element is a function of
- pressure
- mass rate of flow
- velocity of flow
- none of the above
Q10 | When working substance is released through nozzles, the direction of reaction will be
- clockwise
- counter clockwise
- either of (A) and (B) above
- direction depends on other design features
Q11 | Though there are no cyclic variations even then rotary compressors need precise balancing because
- It is bulky in size
- it is driven by an electric motor
- cooling arrangement does not exist
- operating speeds are too high
Q12 | In a velocity compounded steam turbine, as steam moves along moving and guide blades
- both pressure and velocity gradually decrease
- Both pressure and velocity gradually increase.
- pressure gradually increases and velocity is low
- pressure is low and velocity gradually decreases
Q13 | Generally, steam turbines in power stations operate at
- 3000 rpm
- 375 rpm
- 1000 rpm
- 1500 rpm
Q14 | An ideal fluid for vapour turbine cycle should have
- low critical temperature with high pressure
- high critical temperature with low pressure
- high critical temperature with high pressure
- low critical temperature with low presure
Q15 | Overall efficiency of a gas turbine is
- less than Diesel cycle efficiency
- more than Otto or Diesel cycle efficiency
- equal to Rankine cycle efficiency
- equal to Carnot cycle efficiency
Q16 | In gas turbines, intercooling results in
- decrease in net output and increase in thermal efficiency
- decrease in net output as well as thermal efficiency
- increase in net output as well as thermal efficiency
- increase in net output but decrease in thermal efficiency
Q17 | Maximum delivery pressure in case of rotary compressors is usually restricted to
- 5 atmospheres
- 10 atmospheres
- 2 atmospheres
- 20 atmospheres
Q18 | For efficient operation of axial flow compressors the blades are made
- aerofoil section
- forward curved
- straight
- slightly curved
Q19 | Under standard atmospheric condition, the velocity of air is
- 236 m/s
- 436 m/s
- 336 m/s
- 536 m/s
Q20 | A diffuser
- converts thermal energy into kinetic energy
- converts pressure energy into kinetic energy
- converts kinetic energy into thermal energy
- converts potential energy into kinetic energy
Q21 | Which of the following is a positive displacement rotory compressor?
- Roots blower
- Centrifugal compressor
- Axial flow compressor
- All of the above
Q22 | In which of the following heat exchanger, heat is extracted from air?
- Regenerator
- Reheater
- Intercooler
- All of the above
Q23 | The following property is the most important for material used for gas turbine blades
- Fatigue
- Strength against bending
- Strength against direct force
- Group
Q24 | Which of the following fluid can be used in binary vapour cycle?
- Mercury
- Diphenyl oxide
- Aluminium bromide
- any of the above
Q25 | A control volume has an inlet area of 0.1 m2 and exit area of 0.05 m2. The density is 3.89 kg/m2 and constant. If the inlet velocity is 30 m/s, the force on the control volume will be
- 350 N
- 150 N
- 50 N
- 250 N