**n-BUTANE or R600**

N-BUTANE and R600 provide high accuracy thermodynamic and transport properties for normal butane (R600, Molar mass = 58.122 g/mol) using the Fundamental (or Helmholtz Free Energy) Equation of State described by:

Miyamoto, H., and Watanabe, K.,

"A thermodynamic property model for fluid-phase n-butane,"

Int. J. Thermophys., 22(2):459-475, 2001.

The equation of state is valid for temperatures between 134.87 K (the triple point temperature) and 589 K at pressures up to 69 MPa. ** ** The default reference state is the IIR standard for which: h=200.0 kJ/kg, s=1.0 kJ/kg-K. The reference state can be changed using the $Reference directive.

Thermal conductivity data are provided by:

R.A. Perkins, M.L.V. Ramires, C.A. Nieto de Castro, L. Cusco,

"Measurement and correlation of the thermal conductivity of butane from 135 K to 600 K at pressures to 70 MPa,"

J. Chem. Eng. Data **47** (2002).

Viscosity information is provided by:

B.A. Younglove and J.F. Ely,* *

*"Thermophysical Properties of Fluids. II Methane, Ethane, Propane, Isobutane and Normal Butane"*,

J. Phys. Chem. Ref. Data Vol. 16, No. 4, 1987.

Surface tension data are provided through a correlation developed by:

G.R. Somayajulu

"A Generalized Equation for Surface Tension from the Triple Point to the Critical Point"

International Journal of Thermophysics, Vol. 9, No. 4, 1988

Note that N-BUTANE and R600 all provide thermodynamic properties assuming real fluid behavior. Use C4H10 for ideal gas properties of normal butane consistent with reference states used in combustion calculations.