huber_2018#
M. L. Huber, “Models for Viscosity, Thermal Conductivity, and Surface Tension of Selected Pure Fluids as Implemented in REFPROP v10.0”, NIST Interagency Report 8209 (2018)
Source record · Catalogue · Review register
DOI: 10.6028/nist.ir.8209
Source kind: fit
Recorded technique: The transport models of REFPROP 10 for fluids without a reference correlation: extended corresponding states with a reference fluid (nitrogen for the four gases here), whose dilute-gas viscosity is Chapman-Enskog theory with a Lennard-Jones collision integral and a correction factor F_c fitted, per fluid, to dilute-gas data. The NIST Chemistry WebBook (SRD 69) evaluates these models.
Materials in structured entries: Kr, N2O, Ne, Xe
Dataset quantities: None recorded.
Contents: 0 datasets; 4 formulas.
Curation notes#
Identity VALIDATED by the library. Pages are the report’s pdf pages.
THE DILUTE-GAS VISCOSITY (pdf p. 9): Eq. (6), eta* = 5 sqrt(m pi k_B T) / (16 pi sigma^2 Omega(2,2)); Eq. (7), Neufeld et al.’s collision integral without its sinusoidal term, Omega(2,2) = 1.16145 T*^-0.14874 + 0.52487 exp(-0.77320 T*) + 2.16178 exp(-2.43787 T*), valid for 0.3 < T* < 100, T* = k_B T/epsilon; the dilute viscosity is eta* times F_c. Table 1 (pdf p. 262): neon M = 20.179 g/mol, epsilon/k_B = 45.58 K, sigma = 0.2707 nm; krypton 83.798, 178.9 K, 0.3655 nm; xenon 131.293, 260.91 K, 0.3929 nm; nitrous oxide 44.0128, 232.4 K, 0.3828 nm. Table 2 (pdf p. 265): F_c = 0.989544 (neon), 1.008291 (krypton), 1.0012 (xenon), 1 (nitrous oxide), each with nitrogen as the reference fluid. All read from the library’s tables and text, 2026-09-30.
THE CONSTANT. Table 7’s check values of eta* (pdf p. 274: neon 6.006075 uPa s at 40 K, krypton 16.32999 at 188.5 K, xenon 20.11099 at 260.8 K, nitrous oxide 13.86694 at 278.6 K) are reproduced to 2.4e-7 by eta* = 0.026692 sqrt(M T)/(sigma^2 Omega) uPa s (M in g/mol, sigma in nm), REFPROP’s constant; Eq. (6) with CODATA’s k_B gives 1.38e-4 more (computed 2026-09-30). optmat uses 0.026692, the report’s own check values and the WebBook’s tables; the difference is far below every stated uncertainty.
F_c. For neon, krypton and xenon F_c was adjusted so that the dilute-gas viscosity at 25 C and 0.1 MPa agrees with the reference values of Assael et al. (2018) (sections 6.9.1-6.9.3), which are therefore not an independent check. For nitrous oxide F_c = 1.
UNCERTAINTY (expanded, coverage factor two, ‘approximately a 95 % confidence interval’, pdf p. 14): neon, 2 % in the supercritical region at atmospheric pressure (section 6.9.1, pdf p. 185); krypton, 3 % in the gas phase at atmospheric pressure (6.9.2, p. 188); xenon, 0.7 % in the vapour phase (6.9.3, p. 191); nitrous oxide, 5 % in the gas phase (6.11.2, p. 201). The WebBook’s pages state 3 %, 3 %, 1 % and 10 % for the same models; the report governs. optmat takes each gas’s equation-of-state temperatures within Eq. (7)’s 0.3 < T* < 100.
THE WEBBOOK TABLES (data/external/nist_webbook, captured 2026-09-30) give the models’ viscosity at 0.1 MPa, 200-400 K: they exceed the dilute values by 0.013 % (neon), 0.13 % (krypton), 0.21 % (xenon) and 0.21 % (nitrous oxide) at 298.15 K, and by 0.028 %, 0.33 %, 0.54 % and 0.52 % at 200 K, the density term, falling with temperature (tests/test_transport.py).
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
No datasets are recorded.
Formulas#
huber_2018/eq6_eq7_Ne#
{
"id": "eq6_eq7_Ne",
"material": "Ne",
"equation": "Eqs. (6)-(7), pdf p. 9; Tables 1-2, pdf pp. 262, 265",
"printed": "eta* = 5 sqrt(m pi k_B T)/(16 pi sigma^2 Omega(2,2)) F_c; Omega(2,2) = 1.16145 T*^-0.14874 + 0.52487 exp(-0.77320 T*) + 2.16178 exp(-2.43787 T*)",
"variable": "T* = k_B T/epsilon, 0.3 < T* < 100; eta* = 0.026692 sqrt(M T)/(sigma^2 Omega) F_c in uPa s, M in g/mol, sigma in nm",
"range": "0.3 < T* < 100",
"coefficients": {
"prefactor": "0.026692",
"molar_mass": "20.179",
"epsilon_k": "45.58",
"sigma_nm": "0.2707",
"f_c": "0.989544"
},
"check": "Table 7: 6.006075 uPa s at 40 K, reproduced to 6e-8."
}
huber_2018/eq6_eq7_Kr#
{
"id": "eq6_eq7_Kr",
"material": "Kr",
"equation": "Eqs. (6)-(7), pdf p. 9; Tables 1-2, pdf pp. 262, 265",
"printed": "eta* = 5 sqrt(m pi k_B T)/(16 pi sigma^2 Omega(2,2)) F_c; Omega(2,2) = 1.16145 T*^-0.14874 + 0.52487 exp(-0.77320 T*) + 2.16178 exp(-2.43787 T*)",
"variable": "T* = k_B T/epsilon, 0.3 < T* < 100; eta* = 0.026692 sqrt(M T)/(sigma^2 Omega) F_c in uPa s, M in g/mol, sigma in nm",
"range": "0.3 < T* < 100",
"coefficients": {
"prefactor": "0.026692",
"molar_mass": "83.798",
"epsilon_k": "178.9",
"sigma_nm": "0.3655",
"f_c": "1.008291"
},
"check": "Table 7: 16.32999 uPa s at 188.5 K, reproduced to 1.7e-7."
}
huber_2018/eq6_eq7_Xe#
{
"id": "eq6_eq7_Xe",
"material": "Xe",
"equation": "Eqs. (6)-(7), pdf p. 9; Tables 1-2, pdf pp. 262, 265",
"printed": "eta* = 5 sqrt(m pi k_B T)/(16 pi sigma^2 Omega(2,2)) F_c; Omega(2,2) = 1.16145 T*^-0.14874 + 0.52487 exp(-0.77320 T*) + 2.16178 exp(-2.43787 T*)",
"variable": "T* = k_B T/epsilon, 0.3 < T* < 100; eta* = 0.026692 sqrt(M T)/(sigma^2 Omega) F_c in uPa s, M in g/mol, sigma in nm",
"range": "0.3 < T* < 100",
"coefficients": {
"prefactor": "0.026692",
"molar_mass": "131.293",
"epsilon_k": "260.91",
"sigma_nm": "0.3929",
"f_c": "1.0012"
},
"check": "Table 7: 20.11099 uPa s at 260.8 K, reproduced to 2.4e-7."
}
huber_2018/eq6_eq7_N2O#
{
"id": "eq6_eq7_N2O",
"material": "N2O",
"equation": "Eqs. (6)-(7), pdf p. 9; Tables 1-2, pdf pp. 262, 265",
"printed": "eta* = 5 sqrt(m pi k_B T)/(16 pi sigma^2 Omega(2,2)) F_c; Omega(2,2) = 1.16145 T*^-0.14874 + 0.52487 exp(-0.77320 T*) + 2.16178 exp(-2.43787 T*)",
"variable": "T* = k_B T/epsilon, 0.3 < T* < 100; eta* = 0.026692 sqrt(M T)/(sigma^2 Omega) F_c in uPa s, M in g/mol, sigma in nm",
"range": "0.3 < T* < 100",
"coefficients": {
"prefactor": "0.026692",
"molar_mass": "44.0128",
"epsilon_k": "232.4",
"sigma_nm": "0.3828",
"f_c": "1"
},
"check": "Table 7: 13.86694 uPa s at 278.6 K, reproduced to 2e-8."
}
Corrections#
No dataset errata are recorded in this source record.
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.