muzny_2013
==========

C\. D\. Muzny, M\. L\. Huber and A\. F\. Kazakov, "Correlation for the Viscosity of Normal Hydrogen Obtained from Symbolic Regression", J\. Chem\. Eng\. Data 58, 969 \(2013\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/muzny_2013.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1021/je301273j <https://doi.org/10.1021/je301273j>`__

**Source kind:** fit

**Recorded technique:** A correlation of the viscosity of normal hydrogen from the triple point to 1000 K and 200 MPa\: a dilute\-gas term of the Chapman\-Enskog form with an effective cross section fitted to the primary dilute\-gas data, an initial\-density term, and a residual term whose functional form was found by symbolic regression; densities from Leachman et al\.'s equation of state\.

**Materials in structured entries:** H2

**Dataset quantities:** None recorded.

**Contents:** 0 datasets; 1 formula.

Curation notes
--------------

Identity VALIDATED by the library\. Printed pp\. 969\-979; p\. = pdf page \+ 968\.

THE DILUTE VISCOSITY \(p\. 975, Eqs\. 3\-4; Table 2, p\. 971\)\: eta0\(T\) = 0\.021357 \(M T\)^0\.5 / \(sigma^2 S\*\(T\*\)\), in uPa s, M = 2\.01588 g/mol, sigma in nm, with ln S\*\(T\*\) = sum\_{i=0}^{4} a\_i \(ln T\*\)^i, a = 2\.09630e\-1, \-4\.55274e\-1, 1\.43602e\-1, \-3\.35325e\-2, 2\.76981e\-3, T\* = T/\(epsilon/k\), sigma = 0\.297 nm and epsilon/k = 30\.41 K \(Behnejad and Miralinaghi's values, p\. 975\)\.

RANGE AND UNCERTAINTY \(abstract, p\. 969\)\: the correlation covers the triple point to 1000 K and extrapolates 'in a physically reasonable manner to 2000 K'; 'For the limited range of 200 K to 400 K at pressures up to 0\.1 MPa, the uncertainty is 0\.1 %'\. The dilute\-gas term represents the theoretical values of Mehl et al\. to within 1 % below 1000 K and 3 % at 2000 K \(p\. 975\)\. optmat takes the triple point \(13\.957 K, the equation of state's\) to 1000 K\.

ERRATUM\: Muzny, Huber and Kazakov, J\. Chem\. Eng\. Data 67, 2855 \(2022\), doi\:10\.1021/acs\.jced\.2c00523 \(library\: Muzny\_2022\_ErratumCorrelationViscosity\), corrects Eq\. \(6\) \(Avogadro's number in B\_eta\*\), the sign of the exponent in Eq\. \(7\) and the scale density of Eq\. \(9\)\: the initial\-density and residual terms, not the dilute\-gas Eqs\. \(3\)\-\(4\)\. Its zero\-density check value, 1\.9772 uPa s at 40 K, is reproduced \(1\.97721; checked 2026\-09\-30\)\.

REPRODUCED\: CoolProp 8\.0\.0's hydrogen viscosity \(reference key Muzny\-JCED\-2013\) at 1e\-6 mol/m^3 equals Eqs\. \(3\)\-\(4\) to 8e\-12, 120\-900 K \(computed 2026\-09\-30\)\. The correlation is for normal hydrogen; deuterium has its own \(assael\_1987\)\.

**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
--------

muzny\_2013/eq3\_eq4
~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "eq3_eq4",
     "material": "H2",
     "equation": "Eqs. (3)-(4), p. 975; Table 2, p. 971",
     "printed": "eta0 = 0.021357 (M T)^0.5/(sigma^2 S*(T*)); ln S* = sum_i a_i (ln T*)^i",
     "variable": "T in K, T* = T/(epsilon/k); eta0 in uPa s",
     "range": "triple point to 1000 K",
     "coefficients": {
       "prefactor": "0.021357",
       "a0": "2.09630e-1",
       "a1": "-4.55274e-1",
       "a2": "1.43602e-1",
       "a3": "-3.35325e-2",
       "a4": "2.76981e-3",
       "molar_mass": "2.01588",
       "epsilon_k": "30.41",
       "sigma_nm": "0.297"
     },
     "check": "CoolProp 8.0.0 equals it to 8e-12 (tests/test_transport.py)."
   }

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 :doc:`review register </register>` for the checks and decisions.