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Mechanical Engineering :: Steam Nozzles and Turbines

  1. Superheating of steam is done at

  2. A.

     Constant volume

    B.

     Constant temperature

    C.

     Constant pressure

    D.

     Constant entropy


  3. The action of steam in a steam turbine is

  4. A.

     Static

    B.

     Dynamic

    C.

     Static and dynamic

    D.

     Neither static nor dynamic


  5. The best suited coal for chain or traveling grate stoker boiler is

  6. A.

     Coking coal

    B.

     Non-coking or free burning coal

    C.

     Pulverized coal

    D.

     High sulphur coal


  7. The principal function of a stop valve is to

  8. A.

     Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required

    B.

     Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

    C.

     Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit

    D.

     Increase the temperature of saturated steam without raising its pressure


  9. Which is not correct statement about effect of sulphur in fuel?

  10. A.

     It has heating value

    B.

     It helps in electrostatic precipitation of ash in flue gases

    C.

     It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low

    D.

     It erodes furnace walls


  11. A valve installed between the boiler and the feed pump is

  12. A.

     Blow off cock

    B.

     Feed check valve

    C.

     Steam stop valve

    D.

     None of these


  13. The friction present between the steam and the nozzle surfaces reduces the heat drop by

  14. A.

     10 to 15%

    B.

     15 to 25%

    C.

     25 to 40%

    D.

     40 to 60%


  15. In a boiler, the heat is lost

  16. A.

     To dry flue gases

    B.

     In moisture present in the fuel

    C.

     To steam formed by combustion of hydrogen per kg of fuel

    D.

     All of the above


  17. Duplex feed pumps are used in small steam boilers. These operate on the principle of

  18. A.

     Centrifugal pump

    B.

     Axial flow pump

    C.

     Gear pump

    D.

     Reciprocating pump


  19. The reheat factor is the ratio of the

  20. A.

     Cumulative heat drop to the isentropic heat drop

    B.

     Isentropic heat drop to the heat supplied

    C.

     Total useful heat drop to the total isentropic heat drop

    D.

     None of the above