4. Representation of changes on thermodynamic diagrams

The two most commonly used thermodynamic diagrams are the Mollier diagram (h, S ) and the entropy diagram (T, S ), the properties of which are described in particular in the specialized article in this treatise.

For this reason, we will confine ourselves here to reviewing or adding to the knowledge needed to analyze turbomachinery.

The Mollier diagram is mainly used when the fluid is far from the perfect state, as the direct reading of enthalpy on the ordinate scale facilitates application of the First Principle. This is the preferred method in design offices.

The work W _i and τ _S , expressed as enthalpy differences, is easily concretized here.

The entropy diagram is more instructive, as the areas represent...