RRB/SSC JE Mech: POWER PLANT Quiz 2

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Question 1

In a gas turbine plant, regeneration is done to

• Aincrease compression work
• Bdecrease turbine work
• Climit the maximum temperature
• Dimprove plant efficiency

Question 2

The effect of considering friction in steam nozzle for the same pressure ratio leads to

• AIncrease in dryness fraction of exit steam
• BDecrease in dryness fraction of exit steam
• CNo change in the quality of exit steam
• DDecrease or increase of dryness fraction of exit steam depending upon inlet quality

Question 3

In the T-S diagram of reverse Brayton cycle as shown, the expression for efficiency will be:

• A
• B
• C
• D

Question 4

Efficiency of superheat Rankine cycle is more as compared to normal Rankine cycle as:

• Aenthalpy of main steam is more in case of superheat cycle
• Bmean temperature of heat addition is more for superheat cycle
• Ctemperature of steam is more in condenser
• Dquality of steam is less in condenser

Question 5

In order to control the temperature of steam in a steam generator, a spray type desuperheater is used. It is fed with water at 60 °C. Steam at 90 bar and 500 °C with flow rate 300 tons/hr enters the desuperheater. Neglect any pressure drop due to mixing and heat loss to the surrounding. Also given
h_g (at 90 bar and 500 °C) = 3386.1 kJ/kg
h_f (at 60 °C) = 251.11 kJ/kg
h_g (at 90 bar and 450 °C) = 3256.6 kJ/kg
Amount of water that must be sprayed to maintain steam at 450 °C, is ___________ kg/s.

• A3.4
• B3.6
• C3.8
• D4.0

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