Isothermal Properties for Argon

• Fluid Data
• Auxiliary Data
• References and Notes
• Notes
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The following adjustments were made to the specified data range:

• The specified increment was adjusted to limit the number of points calculated.
• Default values were used in place of limits which were not entered.

Fluid Data

Isothermal Data for T = 273.16 K

Auxiliary Data

Reference States

Additional fluid properties

References and Notes

Equation of state

Tegeler, Ch., Span, R., and Wagner, W., "A New Equation of State for Argon Covering the Fluid Region for Temperatures from the Melting Line to 700 K at Pressures up to 1000 MPa," J. Phys. Chem. Ref. Data, 28(3):779-850, 1999.

The estimated uncertainty in density is less than 0.02% for pressures up to 12 MPa and temperatures up to 340 K with the exception of the critical region and less than 0.03% for pressures up to 30 MPa and temperatures between 235 and 520 K. Elsewhere, the uncertainty in density is generally within 0.2%. In the region with densities up to half the critical density and for temperatures between 90 and 450 K, the estimated uncertainty of calculated speeds of sound is in general less than 0.02%. In the liquid and supercritical regions, the uncertainty is less than 1%. The uncertainty in heat capacities is within 0.3% for the vapor and 2% for the liquid. The formulation gives reasonable extrapolation behavior up to very high pressures (50 GPa) and temperatures (17000 K).

Auxillary model, Cp0

Tegeler, Ch., Span, R., and Wagner, W., "A New Equation of State for Argon Covering the Fluid Region for Temperatures from the Melting Line to 700 K at Pressures up to 1000 MPa," J. Phys. Chem. Ref. Data, 28(3):779-850, 1999.

Auxillary model, PX0

Tegeler, Ch., Span, R., and Wagner, W., "A New Equation of State for Argon Covering the Fluid Region for Temperatures from the Melting Line to 700 K at Pressures up to 1000 MPa," J. Phys. Chem. Ref. Data, 28(3):779-850, 1999.

Auxillary model, PH0

Tegeler, Ch., Span, R., and Wagner, W., "A New Equation of State for Argon Covering the Fluid Region for Temperatures from the Melting Line to 700 K at Pressures up to 1000 MPa," J. Phys. Chem. Ref. Data, 28(3):779-850, 1999.

Viscosity

Lemmon, E.W. and Jacobsen, R.T, "Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air," Int. J. Thermophys., 25:21-69, 2004.

The uncertainty is 0.5% in the dilute gas. Away from the dilute gas (pressures greater than 1 MPa and in the liquid), the uncertainties are as low as 1% between 270 and 300 K at pressures less than 100 MPa, and increase outside that range. The uncertainties are around 2% at temperatures of 180 K and higher. Below this and away from the critical region, the uncertainties steadily increase to around 5% at the triple points of the fluids. The uncertainties in the critical region are higher.

Auxillary model, the collision integral

Lemmon, E.W. and Jacobsen, R.T, 2004.

Thermal conductivity

The uncertainty for the dilute gas is 2% with increasing uncertainties near the triple point. For the non-dilute gas, the uncertainty is 2% for temperatures greater than 170 K. The uncertainty is 3% at temperatures less than the critical point and 5% in the critical region, except for states very near the critical point.

Auxillary model, the thermal conductivity critical enhancement

Lemmon, E.W. and Jacobsen, R.T, 2004.

Surface tension

Dielectric constant

Metling line

Sublimation line

Lemmon, E.W., 2002.

Vapor pressure

Functional Form: P=Pc*EXP[SUM(Ni*Theta^ti)*Tc/T] where Theta=1-T/Tc, Tc and Pc are the reducing parameters below, which are followed by rows containing Ni and ti.

Saturated liquid density

Functional Form: D=Dc*EXP[SUM(Ni*Theta^(ti/3))] where Theta=1-T/Tc, Tc and Dc are the reducing parameters below, which are followed by rows containing Ni and ti.

Saturated liquid volume

Equation of Tegeler appears to be wrong, and new equation was fitted here.

Functional Form: D=Dc*EXP[SUM(Ni*Theta^(ti/3))*Tc/T] where Theta=1-T/Tc, Tc and Dc are the reducing parameters below, which are followed by rows containing Ni and ti.

Notes

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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