Multiple Choice Questions on Steam Boilers and Turbines - Set 15 - ObjectiveBooks

# Practice Test: Question Set - 15

1. Which of the following is a fire tube boiler?
(A) Lancashire boiler
(B) Babcock and Wilcox boiler
(C) Yarrow boiler
(D) None of these

2. In forced recirculation type boiler,
(A) Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
(B) Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
(C) Feed pump is employed to supplement natural circulation in water wall type furnace
(D) Water is converted into steam in one pass without any recirculation

3. When the nozzle operates with the maximum mass flow, the nozzle is said to be
(A) Choked
(B) Under-damping
(C) Over-damping
(D) None of these

4. The average value of diagram factor lies between
(A) 0.2 to 0.5
(B) 0.5 to 0.65
(C) 0.65 to 0.9
(D) 0.8 to 1.2

5. A safety valve in a locomotive starts leaking. The leaking medium will be
(A) Water
(B) Dry steam
(C) Wet steam
(D) Super heated steam

6. Which of the following statement is wrong?
(A) The critical pressure gives the velocity of steam at the throat equal to the velocity of sound
(B) The flow in the convergent portion of the nozzle is subsonic
(C) The flow in the divergent portion of the nozzle is supersonic
(D) To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary

7. The ratio of the energy required to produce the artificial draught (expressed in meters head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
(A) Efficiency of the boiler
(B) Efficiency of the chimney
(C) Efficiency of the fan
(D) Power of the boiler

8. Which device is used in thermal power plants to reduce level of pollution?
(A) Induced draft fan
(B) Smoke meter
(C) Chimney
(D) Precipitator

9. The expansion of steam, as it flows over the blades in reaction turbine, represents
(A) Isothermal process
(B) Isentropic process
(C) Throttling process
(D) Free expansion process

10. Clearance ratio is the ratio of
(A) Clearance volume to the swept volume
(B) Clearance volume to the volume at cut-off
(C) Volume at cut-off to the swept volume
(D) Swept volume to the clearance volume

11. The ultimate analysis of fuel lists
(A) Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume
(B) Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight
(C) Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
(D) Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

12. Which of the following statement is correct?
(A) The expansion of steam in a nozzle follows Rankine cycle
(B) The friction in the nozzle increases the dryness fraction of steam
(C) The pressure of steam at throat is called critical pressure
(D) All of the above

13. The heat balance sheet for the boiler shows the
(A) Complete account of heat supplied by 1 kg of dry fuel and the heat consumed
(B) Moisture present in the fuel
(C) Steam formed by combustion of hydrogen per kg of fuel
(D) All of the above

14. A supercritical boiler is one that operates above the pressure and temperature of following values
(A) 100 kg/cm² and 540°C
(B) 1 kg/cm² and 100°C
(C) 218 kg/cm² abs and 373°C
(D) 218 kg/cm² abs and 540°C

15. Curtis turbine is a
(A) Simple reaction turbine
(B) Velocity compounded turbine
(C) Pressure compounded turbine
(D) Pressure-velocity compounded turbine

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