Steam Tutorial
1. A vessel having a volume of 0.6 m3 contains 3.0 kg of liquid water and water vapour
mixture in equilibrium at a pressure of 0.5 MPa.
Calculate:
(i) Mass and volume of liquid; (1.404 kg & 0.0015 m3)
(ii) Mass and volume of vapour, (1.596 kg & 0.5985 m3)
2. A closed vessel contains 12 m3 of dry saturated steam at 1400 kPa. What is the
temperature and mass of this steam? (195.7°C & 8.52 kg)
3. A vessel having a capacity of 0.05 m3 contains a mixture of saturated water and
saturated steam at a temperature of 245°C. The mass of the liquid present is 10 kg.
Find the following:
(i) The pressure, (3.65 MPa)
(ii) The mass, (10.688 kg)
(iii) The specific volume, (0.004654 m3/kg)
(iv) The specific enthalpy, (1172.77 kJ/kg)
(v) The specific entropy, and (2.9623 kJ/kg K)
(vi) The specific internal energy (1155.78 kJ/kg)
4. Determine the amount of heat, which should be supplied to 2 kg of water at 25°C to
convert it into steam at 5 bar and 0.9 dry.(4864.52 kJ)
5. A certain quantity of steam in a closed vessel of fixed volume of 014 m3 exerts a
pressure of 10 bar at 250°C. If the vessel is cooled so that the pressure falls to 3-6
bar, determine:
(i) the final quality of steam, (0.44)
(ii) the final temperature, (139.87°C)
(ii) the change in internal energy, and (-797.52 kJ)
(iv) the heat transferred during the process. Take kp for superheated steam as 21 kJ/kg
K. (-797.52 kJ.)
6. 1000 kg of steam at a pressure of 16 bar and 0.9 dry is generated by a boiler per hour.
The steam passes through a superheater via boiler stop valve where its temperature
is raised to 380°C. If the temperature of feed water is 30°C, determine:
(i) The total heat supplied to feed water per hour to produce wet steam. (2473.08 ×103
kJ)
(ii) The total heat absorbed per hour in the superheater, (586.24 × 103 kJ)
Take specific heat for superheated steam as 2.2 kJ/kg K.
7. Using steam tables, determine the mean specific heat for superheated steam:
(i) at 75 kPa, between 100°C and 150°C; (1.976)
(ii) at 50 kPa, between 300°C and 400°C. (2.034)
8. Find the specific volume, enthalpy and internal energy of wet steam at 1800 kPa,
dryness fraction 0.85.(0.0953 m3/kg, 2508.35 kJ/kg, 2345.75 kJ/kg)
9. A quantity of steam at 10 bar and 0.85 dryness occupies 0.15 m3. Determine the heat
supplied to raise the temperature of the steam to 300°C at constant pressure and
percentage of this heat which appears as external work. (514.7 kJ& 14.1%)
10. A boiler generates 1,400 kg of steam per hour at a pressure of 1800 kPa and 0.95
dry. The steam after leaving the boiler stop valve, passes through 1 superheater
where its temperature is raised to 305°C. If the feed water supplied to the boiler is at
40°C, calculate:
(i) the heat supplied to feed water per hour to produce wet steam, and (35,47,700
kJ/hr)
(ii) the percentage of the heat absorbed in the boiler and in the superheater. Take kp
of superheated steam as 23 kJ/kg K and specific heat of water as 4 187 kJ/kg K. (8876 % & 11-24 %)
11. Two boilers one with superheater and other without superheater are delivering equal
quantities of steam into a common main. The pressure in the boilers and main is 20
bar. The temperature of steam from a boiler with a superheater is 350°C and
temperature of the steam in the main is 250°C. Determine the quality of steam
supplied by the other boiler. Take cps = 2.25 kJ/kg. (0.925)
12. Steam enters an engine at a pressure 10 bar absolute and 400°C. It is exhausted at
0.2 bar. The steam at exhaust is 0.9 dry. Find:
(i) Drop in enthalpy; (889.9 kJ/kg)
(ii) Change in entropy (0.2634 kJ/kg K (decrease))
13. Steam at a pressure of 1.1 bar and 0.95 dry is passed into a tank containing 90 kg of
water at 25°C. The mass of tank is 12.5 kg and specific heat of metal is 0.42 kJ/kg K.
If the temperature of water rises to 40°C after the passage of the steam, determine
the mass of steam condensed. Neglect radiation and other losses. (2.488 kg)
14. A throttling calorimeter is used to measure the dryness fraction of the steam in the
steam main which has steam flowing at a pressure of 8 bar. The steam after passing
through the calorimeter is at 1 bar pressure and 115°C. Calculate the dryness fraction
of the steam in the main. Take cps = 2.1 kJ/kg K. (0.97)
15. The following data were obtained in a test on a combined separating and throttling
calorimeter: Pressure of steam sample = 15 bar, pressure of steam at exit = 1 bar,
temperature of steam at the exit = 150°C, discharge from separating calorimeter = 0.5
kg/min, discharge from throttling calorimeter = 10 kg/min. Determine the dryness
fraction of the sample steam. (0.946)
16. Steam at a pressure of 600 kPa is passed into a tank containing water where it is
condensed. Before the steam is introduced in the tank, the mass and temperature of
water in the tank is 74 kg and 15°C respectively. The water equivalent of tank is one
kg. Calculate the dryness fraction of steam as it enters the tank if 2.5 kg of steam is
condensed in the tank and the resulting temperature of the mixture is 35 °C. Assume
no losses and specific heat of water as 4.187 kJ/kg K. (0.95)