Example Problem - Evaluating Changes in Entropy
Channel: Thermofluids
Date: 2020-04-22

"A rigid tank is divided into two equal parts by a partition. One part of the tank contains 2.5 kg of compressed water at 400 kPa and 60°C while the other part is evacuated. The partition is now removed, and the water expands to fill the entire tank.
Determine:
d) The entropy change of water during this process, if the final pressure in the tank is 40 kPa. (kJ/K)
e) The entropy change of the surrounding air, assuming the temperature of that air is constant at 25°C (kJ/K)
f) The entropy generated (kJ/K)
g) Given your answer to part (c), what can you conclude about this process? Support your conclusion.
h) What is the theoretical maximum pressure possible (i.e. “best case scenario”) at the end of the process? (kPa)"

PDF of Chapter 6 Notes: https://sdsu.box.com/s/5f3p7xqhrh5r7azx5tcisvxthbjs5gmg