Question

A sample of wet steam is passed through a simple throttling calorimeter. The steam entry pressure recorded on a gauge is 9 bar. Immediately after throttling, the temperature is 110 °C, where the steam is at atmospheric pressure of 1 bar. Calculate the dryness fraction of the steam sample.

Answer 1

After throttling
h2 = 2697.6 kJ/kg
Before throttling
h1 = hf + xhfg = 763 + x2015 (from the tables https://www.simetric.co.uk/si_steam.htm)
h1 = h2
We get
763 kJ/kg + x2015 kJ/kg = 2697.6 kJ/kg
x = 0.9495