Paper 18: A New Graphical Representation of the Thermodynamic Properties of a Fluid in Motion,with Particular Reference to Air at High Velocities,Temperatures,and Altitudes *

Diagrams are described which represent the equilibrium thermodynamic properties of air, account being taken of dissociation. The ordinates are the logarithm of specific enthalpy in both cases; the two abscissae are the logarithm of specific volume in one case and that of velocity in the other. The specific enthalpy varies from 10 to 10⁴ Btu/lb, the specific volume from 1 to 10⁶ ft³/lb, and the velocity from 10² to 10⁵ ft/s; the corresponding ranges of temperature and pressure are respectively 45°R to 11 700°R and 10-⁴ arm to 10² atm.

It is shown how constructions on the diagrams may be used for the representation and calculation of steady-flow processes involving compression and expansion, heating and cooling, shock waves, detonations, mixing, and combinations of these processes.