Diagrams are graphical representations of complex correlations, such as temperature-entropy and enthalpy-entropy diagrams, for example. Drawing diagrams to scale makes them much more useful than cartoons, which only illustrate principles rather than facts.
Sankey diagrams are suitable for visualizing the energy flows between different components of a gas turbine. The width of the connections represents the size of the energy flow, the product of mass flow and specific enthalpy. Grassmann diagrams show exergy flows, the product of mass flow and specific exergy.
Interested in using Sankey or Grassmann diagrams to enhance your publications or lectures? I can create such diagrams for you for free if you send me your GasTurb input file!