# A quantity of steam at 10 bar and 0.85 dry… solved problem

#### 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. Take specific heat of superheated steam as 2.2 kJ/kg K.

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. Take specific heat of superheated steam as 2.2 kJ/kg K.

1. A spherical vessel of 0.9 m3 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.

2. 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.

3. 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. Take specific heat of superheated steam as 2.2 kJ/kg K.