Aspen Physical Property System - Physical Property Models

Dean-Stiel Pressure Correction
The residual vapor viscosity or the pressure correction to low pressure vapor
viscosity by Dean and Stiel is:
Where � v (p = 0) is obtained from a low pressure viscosity model (for
example, General Pure Component Vapor Viscosity). The dimensionlessmaking
factor � is:
�
Tc
262 3 Transport Property Models
=
=
M =
pc
Vcm
Zcm
=
=
=
�rm = Vcm / Vm v
The parameter Vm v is obtained from Redlich-Kwong equation-of-state.
Parameter
Name/Element
Symbol Default MDS Lower
Limit
Upper
Limit
MW M i — — 1.0 5000.0 —
Units
VC V ci — — 0.001 3.5 MOLE-VOLUME
IAPS Viscosity for Water
The IAPS viscosity models, developed by the International Association for
Properties of Steam, calculate vapor and liquid viscosity for water and steam.
These models are used in option sets STEAMNBS and STEAM-TA.
The general form of the equation for the IAPS viscosity models is:
�w=fcn(T, p)
Where:
fcn = Correlation developed by IAPS
The models are only applicable to water. There are no parameters required
for the models.