#### If a certain amount of steam is produced at a pressure of 8 bar and dryness fraction 0.8. Calculate : (i) External work done during evaporation. (ii) Internal latent heat of steam.

If a certain amount of steam is produced at a pressure of 8 bar and dryness fraction 0.8. Calculate :

(i) External work done during evaporation.

(ii) Internal latent heat of steam.

1. A pressure cooker contains 1.5 kg of saturated steam at 5 bar. Find the quantity of heat which must be rejected so as to reduce the quality to 60 % dry. Determine the pressure and temperature of the steam at the new state.

2. A spherical vessel of 0.9 m^{3} capacity contains steam at 8 bar and 0.9 dryness fraction. Steam is blown off until the pressure drops to 4 bar. The valve is then closed and the steam is allowed to cool until the pressure falls to 3 bar. Assuming that the enthalpy of steam in the vessel remains constant during blowing off periods, determine :

(i) The mass of steam blown off ;

(ii) The dryness fraction of steam in the vessel after cooling ;

(iii) The heat lost by steam per kg during cooling.

3. If a certain amount of steam is produced at a pressure of 8 bar and dryness fraction 0.8. Calculate :

(i) External work done during evaporation.

(ii) Internal latent heat of steam.

4. A quantity of steam at 10 bar and 0.85 dryness occupies 0.15 m^{3}. 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. Take specific heat of superheated steam as 2.2 kJ/kg K.

5. Find the specific volume, enthalpy and internal energy of wet steam at 18 bar, dryness fraction 0.85.

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