laesecke_2017
=============

A\. Laesecke and C\. D\. Muzny, "Reference Correlation for the Viscosity of Carbon Dioxide", J\. Phys\. Chem\. Ref\. Data 46, 013107 \(2017\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/laesecke_2017.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1063/1\.4977429 <https://doi.org/10.1063/1.4977429>`__

**Source kind:** fit

**Recorded technique:** A reference correlation of the viscosity of carbon dioxide\: the zero\-density limit from Hellmann's ab initio values scaled by 1\.0055 to the most accurate measurements, in a form found by symbolic regression, plus initial\-density and residual terms fitted to measurements, with densities from Span and Wagner's equation of state\.

**Materials in structured entries:** CO2

**Dataset quantities:** None recorded.

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

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

Identity VALIDATED by the library\. The library's copy is the NIST author manuscript; pages cited are its pdf pages\.

THE ZERO\-DENSITY VISCOSITY \(Eq\. 4, pdf p\. 10; Table 2, pdf p\. 57\)\: eta0\(T\) = 1\.0055 sqrt\(T\) / \[a0 \+ a1 T^\(1/6\) \+ a2 exp\(a3 T^\(1/3\)\) \+ \(a4 \+ a5 T^\(1/3\)\)/exp\(T^\(1/3\)\) \+ a6 sqrt\(T\)\], in mPa s with T in K; a0\.\.a6 = 1749\.354893188350, \-369\.069300007128, 5423856\.34887691, \-2\.21283852168356, \-269503\.247933569, 73145\.021531826, 5\.34368649509278\. It represents Hellmann's values within \-0\.059 % to \+0\.026 % and has no singularity below 100 K \(pdf p\. 10\)\.

UNCERTAINTY \(pdf p\. 22\)\: 'Below the triple\-point pressure of 0\.51795 MPa, the uncertainty of the correlation is 0\.2 % from 200 K to 700 K and 1 % up to 2000 K'; the estimates build on the expanded uncertainties of the data sources\. Extrapolations below 200 K and above 2000 K are called physically realistic\. optmat takes 200\-2000 K, where an uncertainty is stated\.

REPRODUCED\: CoolProp 8\.0\.0's carbon dioxide viscosity \(reference key Laesecke\-JPCRD\-2017\-CO2\) at 1e\-6 mol/m^3 equals Eq\. \(4\) to 4e\-10, 120\-900 K \(computed 2026\-09\-30\)\.

**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
--------

laesecke\_2017/eq4
~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "eq4",
     "material": "CO2",
     "equation": "Eq. (4), pdf p. 10; Table 2, pdf p. 57 (author manuscript)",
     "printed": "eta0 = 1.0055 sqrt(T)/[a0 + a1 T^(1/6) + a2 exp(a3 T^(1/3)) + (a4 + a5 T^(1/3))/exp(T^(1/3)) + a6 sqrt(T)]",
     "variable": "T in K; eta0 in mPa s",
     "range": "200-2000 K (stated uncertainty)",
     "coefficients": {
       "scale": "1.0055",
       "a0": "1749.354893188350",
       "a1": "-369.069300007128",
       "a2": "5423856.34887691",
       "a3": "-2.21283852168356",
       "a4": "-269503.247933569",
       "a5": "73145.021531826",
       "a6": "5.34368649509278"
     },
     "check": "CoolProp 8.0.0 equals it to 4e-10 (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.