Thermal Engineering Mid - II, November - 2014

1.Water tube boilers produce steam at a ________ pressure that that of fire tube boilers
  • Lower
  • equal
  • Higher
  • Cannot be determined
Answer: C
2.A device used to increase the temperature of saturated steam without raising its pressure is called
  • Blow off cock
  • Fusible plug
  • Super Heater
  • Economiser
Answer: C
3.Boiler efficiency is a function of
  • Mass of water evaporated
  • Mass of fuel used
  • Calorific value of fuel used
  • All
Answer: D
4.The effect of air leakage in condenser leads to
  • Lower thermal efficiency
  • Increased requirement of cooling water
  • Reduced heat transfer
  • All of the above
Answer: D
5.In a multistage reaction turbine from first stage to last stage specific volume
  • Increases
  • Decreases
  • Remains constant
  • None
Answer: A
6.For shock less entry and exit the steam should enter the blades
  • Radially
  • Tangentially
  • Axially
  • Parallel
Answer: B
7.For reaction turbines which of the following governing is not used
  • Throttle governing
  • By-pass governing
  • Nozzle control governing
  • None of the above
Answer: C
8.Evaporative type of condenser has
  • Steam in pipes surrounded by water
  • Water in pipes surrounded by steam
  • Either of the above
  • None of the above
Answer: A
9.A closed cycle gas turbine works on _________ cycle.
  • Rankine
  • Joule
  • Atkinson
  • Brayton
Answer: B
10.The blades of a gas turbine are generally made up of
  • Cast iron
  • Cast steel
  • Nickel cobalt alloy
  • Aluminium
Answer: C
11.The ratio of actual vacuum to the ideal vacuum in a condenser is called ______________.
Answer: Vacuum efficiency
12.The critical pressure ratio for initially dry saturated steam is_____________.
Answer: 0.577
13.The flow of steam is supersonic in ________________ portion of the nozzle.
Answer: In the divergent
14.Power produced in reaction turbine is given by ____________.
Answer: P = m(Vw + Vw1)Vb watts
15.The blade friction in the impulse turbine reduces the velocity of steam by ____________ while passes over the blades.
Answer: 10 to 15%)
16.For a given power an impulse turbine as compared to a reaction turbine has ____________ row of blades.
Answer: More
17.Heat rate of steam turbines is expressed as _______________.
Answer: KJ/kWh
18.Stage efficiency of steam turbine is equal to ________________.
Answer: Nozzle Efficiency x Blade Efficiency
19.Compared to IC engine, the maximum combustion pressure in gas turbine is ______________.
Answer: Less
20.A constant volume combustion gas turbine works on __________________ cycle.
Answer: Arkinson