Aspen Physical Property System - Physical Property Models

Parameter Symbol Default MDS Lower
Name/Element
Limit
3 Transport Property Models 283
Upper
Limit
Units
STKPAR/2 � i ST fcn(T bi, V bi, p i) x — — LENGTH
LJPAR/1 (� i/k) LJ
LJPAR/2 � i LJ
References
fcn(T ci, � i) x — — TEMPERATURE
fcn(T ci, p ci, � i) x — — LENGTH
R.C. Reid, J.M. Praunitz, and B.E. Poling, The Properties of Gases and Liquids,
4th ed., (New York: McGraw-Hill, 1987), p. 587.
Chapman-Enskog-Wilke-Lee (Mixture)
The diffusion coefficient of a gas into a gas mixture at low pressures is
calculated using an equation of Bird, Stewart, and Lightfoot by default (option
code 0):
If the first option code is set to 1, Blanc's law is used instead:
The binary diffusion coefficient Dij v (p = 0) at low pressures is calculated using
the Chapman-Enskog-Wilke-Lee model. (See Chapman-Enskog-Wilke-Lee
(Binary).)
You must provide parameters for this model.
Parameter
Name/Element
Symbol Default MDS Lower
Limit
Upper
Limit
DVBLNC — 1 x — — —
Units
DVBLNC is set to 1 for a diffusing component and 0 for a non-diffusing
component.
References
R.C. Reid, J.M. Prausnitz, and B.E. Poling, The Properties of Gases and
Liquids, 4th ed., (New York: McGraw-Hill, 1987), p. 597.
Dawson-Khoury-Kobayashi (Binary)
The binary diffusion coefficient Dij v at high pressures is calculated from the
Dawson-Khoury-Kobayashi model: