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Aspen Physical Property System - Physical Property Models

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�i = Viscosity of component i (N-sec/sqm)<br />

log = Common logarithm (base 10)<br />

f = An adjustable parameter, typically in the<br />

range of 0.5 to 1.0<br />

The individual component viscosities are calculated by the General Pure<br />

Component Liquid Viscosity model. The parameter f can be specified by<br />

setting the value for MULOGF for the first component in the component list<br />

(as defined on the Components | Specifications | Selection sheet).<br />

Parameter<br />

Name/Element<br />

3 Transport <strong>Property</strong> <strong>Models</strong> 253<br />

Symbol Default MDS Lower<br />

Limit<br />

Upper<br />

Limit<br />

MULOGF f 1.0 — 0.0 2.0 —<br />

Units<br />

† "Petroleum Refining, 1 Crude Oil, Petroleum Products, Process Flowsheets",<br />

Institut Francais du Petrole Publications, 1995, p. 130.<br />

General Pure Component Vapor Viscosity<br />

The <strong>Aspen</strong> <strong>Physical</strong> <strong>Property</strong> <strong>System</strong> has several submodels for calculating<br />

pure component low pressure vapor viscosity. It uses parameter TRNSWT/2<br />

to determine which submodel is used. See Pure Component Temperature-<br />

Dependent Properties for details.<br />

If TRNSWT/2 is This equation is used And this parameter is<br />

used<br />

0 Chapman-Enskog-<br />

Brokaw<br />

STKPAR, LJPAR<br />

102 DIPPR MUVDIP<br />

301 PPDS MUVPDS<br />

302 PPDS kinetic theory MUVCEB<br />

401 IK-CAPE polynomial<br />

equation<br />

402 IK-CAPE Sutherland<br />

equation<br />

503 NIST ThermoML<br />

polynomial<br />

Chapman-Enskog-Brokaw<br />

MUVPO<br />

MUVSUT<br />

MUVTMLPO<br />

The equation for the Chapman-Enskog model is:<br />

Where:<br />

�� =<br />

A parameter � is used to determine whether to use the Stockmayer or<br />

Lennard-Jones potential parameters for �/k (energy parameter) and �<br />

(collision diameter). To calculate �, the dipole moment p and either the

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