# Helium¶

## References¶

### Equation of State¶

D.O. Ortiz-Vega, K.R. Hall, V.D. Arp, and E.W. Lemmon. Equation of state for Helium. Unpublished - coefficients from REPROP with permission, 2013.

### Thermal Conductivity¶

B.A. Hands and V.D. Arp. A Correlation of Thermal Conductivity Data for Helium. Cryogenics, 21(12):697–703, 1981. doi:10.1016/0011-2275(81)90211-3.

### Viscosity¶

V.D. Arp, R.D. McCarty, and D.G Friend. Thermophysical Properties of Helium-4 from 0.8 to 1500 K with Pressures to 2000 MPa - NIST Technical Note 1334 (revised). Technical Report, NIST, 1998.

### Melting Line¶

Frédéric Datchi, Paul Loubeyre, and René LeToullec. Extended and accurate determination of the melting curves of argon, helium, ice (H$_2$O) and hydrogen (H$_2$). Physical Review B, 61(10):6535–6546, 2000. doi:10.1103/PhysRevB.61.6535.

### Surface Tension¶

A. Mulero, I. Cachadiña, and M. I. Parra. Recommended Correlations for the Surface Tension of Common Fluids. J. Phys. Chem. Ref. Data, 41(4):043105–1:13, 2012. doi:10.1063/1.4768782.

## Aliases¶

helium, HELIUM, He, R704

## Fluid Information¶

Parameter, Value
General
Molar mass [kg/mol] 0.004002602
CAS number 7440-59-7
ASHRAE class A1
Formula $$He$$
Acentric factor -0.385
InChI InChI=1/He
InChIKey SWQJXJOGLNCZEY-UHFFFAOYAJ
SMILES [He]
ChemSpider ID 22423
2D image
Limits
Maximum temperature [K] 2000.0
Maximum pressure [Pa] 1000000000.0
Triple point
Triple point temperature [K] 2.1768
Triple point pressure [Pa] 5033.54889666
Critical point
Critical point temperature [K] 5.1953
Critical point density [kg/m3] 72.56717426
Critical point density [mol/m3] 18130.0
Critical point pressure [Pa] 227600.0

## REFPROP Validation Data¶

Note

This figure compares the results generated from CoolProp and those generated from REFPROP. They are all results obtained in the form $$Y(T,\rho)$$, where $$Y$$ is the parameter of interest and which for all EOS is a direct evaluation of the EOS

You can download the script that generated the following figure here: (link to script), right-click the link and then save as... or the equivalent in your browser. You can also download this figure as a PDF.

## Consistency Plots¶

The following figure shows all the flash routines that are available for this fluid. A red + is a failure of the flash routine, a black dot is a success. Hopefully you will only see black dots. The red curve is the maximum temperature curve, and the blue curve is the melting line if one is available for the fluid.

In this figure, we start off with a state point given by T,P and then we calculate each of the other possible output pairs in turn, and then try to re-calculate T,P from the new input pair. If we don’t arrive back at the original T,P values, there is a problem in the flash routine in CoolProp. For more information on how these figures were generated, see CoolProp.Plots.ConsistencyPlots

Note

You can download the script that generated the following figure here: (link to script), right-click the link and then save as... or the equivalent in your browser. You can also download this figure as a PDF.