The diagram below can be used to determine enthalpy versus entropy of water and steam.
The Mollier diagram is useful when analyzing the performance of adiabatic steady-flow processes, such as flow in nozzles, diffusers, turbines and compressors.
The quantity of saturated vapour in unit mass of wet vapour, denoted by x, is referred to as the
dryness fraction, or quality,
of the vapour.