Question

A steel tank contains water at ? = 1.00 MPa and ℎ = 3100 kJ/kg. Determine the following:

a. State of the water; ie whether the water is compressed water or saturated water or superheated vapour? (Hint: Use Saturated water—Pressure table to compare ℎ at ? = 1.00 MPa)

b. Estimate the temperature of the water. (Hint: Use Saturated water—Pressure table or Superheated water, depending on the state you find in a)

c. Other properties of water in the tank can be determined knowing just ? and ℎ only. What postulate is this known as?

2. A 1 m3 pressure vessel operating at 500 kPa leaks causing steam to escape at that pressure. The leak was detected 30 mins after it started in which time the amount of liquid in the vessel decreased by 0.0015 m3 . The leak is due to a corrosion that causes a circular hole of radius 5 mm on the surface of the tank. Saturation conditions can be assumed to exist in the vessel. (Hint: Use property table to determine properties at 500 kPa)

Determine the following:

a. Mass flow rate of the steam

b. Exit velocity of the steam

c. Kinetic energy per unit mass of the steam

d. Flow energy of the steam per unit mass

Answer 1