Question

Steam enters an engine at a pressure 10 bar absolute and 250 °C, it is exhausted at 0.2 bar. The steam at exhaust is 0.9 dry. Find i) Drop in enthalpy ii. Change in entropy​

Answer 1

Answer:

Steam enters an engine at a pressure of 10 bar and 400°C. It is exhausted at 0.2 bar. The steam at exhaust is 0.9 dry. Find the change in entropy (in J/kg K).

Properties of steam and water is given as:

At 10 bar: Tsat = 179.91°C, vf = 0.001127 m3/kg, vg = 0.19444 m3/kg, uf = 761.67 kJ/kg, ufg = 1822 kJ/kg, hf = 762.79 kJ/kg, hfg = 2015.3 kJ/kgm, sf = 2.1386 kJ/kg K, sfg = 6.5864 kJ/kg K

At 0.2 bar: hf = 251.5 kJ/kg, hfg = 2358.4 kJ/kg, sf =