**AIR_ha**

AIR_ha provides thermodynamic properties for the gas mixture composing air using the fundamental equation of state developed by:

E.W. Lemmon, R.T. Jacobsen, S.G. Penoncello, and Daniel Friend

"*Thermodynamic Properties of AIr and Mixtures of Nitrogen, Argon, and Oxygen from 60 to 2000 K at Pressures to 2000 MPa*",

J. Phys. Chem. Ref. Data, Vol. 29, No. 3, 2000.

The thermodynamic property correlations are valid for temperatures between 60 K and 2000 K at pressures up to 2000 MPa.

Note that AIR_ha provides thermodynamic properties assuming real fluid behavior. Use AIR for ideal gas properties of air as found in the air tables of thermodynamic textbooks. At ideal gas conditions, AIR_ha returns the same values as AIR, but requires significantly more computation.

**Transport Properties**:

The transport properties are implemented with the equations provided in:

E.W. Lemmon and R.T. Jacobsen

*"Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air"*,

International Journal of Thermophysics, Vol. 25, No. 1, January 2004, pp. 21-69

The surface tension function of AIR_ha has been fit to data tabulated by Liley and Desai, "Thermophysical Properties of Refrigerants", ASHRAE, 1993, ISBN 1-1883413-10-9. It is valid for temperatures between 70 K and 130 K.