25.12.2012 Views

Aspen Physical Property System - Physical Property Models

Aspen Physical Property System - Physical Property Models

Aspen Physical Property System - Physical Property Models

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Stockmayer parameters or Tb and Vb are needed. The polarity correction is<br />

from Brokaw.<br />

Parameter Symbol Default MDS Lower<br />

Name/Element<br />

Limit<br />

254 3 Transport <strong>Property</strong> <strong>Models</strong><br />

Upper<br />

Limit<br />

MW M i — — 1.0 5000.0 —<br />

MUP p i — — 0.0 5x10 -24<br />

Units<br />

DIPOLEMOMENT<br />

STKPAR/1 (� i/k) ST fcn(T bi, V bi, p i) — X — TEMPERATURE<br />

STKPAR/2 � i ST fcn(T bi, V bi, p i) X — — LENGTH<br />

LJPAR/1 (� i/k) LJ<br />

LJPAR/2 � i LJ<br />

DIPPR Vapor Viscosity<br />

fcn(T ci, � i) X — — TEMPERATURE<br />

fcn(T ci, p ci, � i)<br />

The equation for the DIPPR vapor viscosity model is:<br />

X — — LENGTH<br />

When necessary, the vapor viscosity is extrapolated beyond this temperature<br />

range linearly with respect to T, using the slope at the temperature limits.<br />

(Other DIPPR equations may sometimes be used. See Pure Component<br />

Temperature-Dependent Properties for details.)<br />

PCES uses the DIPPR equation in estimating vapor viscosity.<br />

Parameter<br />

Name/Element<br />

Symbol Default MDS Lower<br />

Limit<br />

Upper<br />

Limit<br />

Units<br />

MUVDIP/1 C 1i — X — — VISCOSITY<br />

MUVDIP/2 C 2i 0 X — — —<br />

MUVDIP/3, 4 C 3i, C 4i 0 X — — TEMPERATURE †<br />

MUVDIP/5 †† 0 X — — —<br />

MUVDIP/6 C 6i 0 X — — TEMPERATURE<br />

MUVDIP/7 C 7i 1000 X — — TEMPERATURE<br />

† If any of C2i through C4i are non-zero, absolute temperature units are<br />

assumed for C1i through C4i. Otherwise, all coefficients are interpreted in user<br />

input temperature units. The temperature limits are always interpreted in<br />

user input units.<br />

†† MUVDIP/5 is not used in this equation. It is normally set to zero. The<br />

parameter is provided for consistency with other DIPPR equations.<br />

PPDS<br />

The PPDS submodel includes both the basic PPDS vapor viscosity equation<br />

and the PPDS kinetic theory vapor viscosity equation. For either equation,<br />

linear extrapolation of viscosity versus T occurs for temperatures outside<br />

bounds.<br />

PPDS Vapor Viscosity<br />

The equation is:

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!