Chung et al. Viscosity Model#
The ChungViscosityPure
pure component gas dynamic viscosity model can be imported from idaes.models.properties.modular_properties.pure
.
Formulation#
The description of the Chung et al. model for viscosity here is derived from that in The Properties of Gases and Liquids, Section 9-4-2. Pure component gas viscosity is given by the formula:
in which \(\mu\) is the dynamic viscosity, \(M\) is the molar mass, \(V_c\) is the critical molar volume, and \(\Omega_v(T)\) is a dimensionless quantity known as the collision integral. \(C\) is a constant with value \(40.785\;\mu\text{P}(\text{mL}/\text{mol})^{2/3}/\sqrt{(\text{g}/\text{mol})\text{K}}\), and
in which \(\omega\) is the acentric factor, \(p_r\) is the reduced molecular dipole moment, and \(\kappa\) is a correction factor, called the association factor, given for certain polar molecules. Values for \(\kappa\) can be found in The Properties of Gases and Liquids, Table 9-1, which in turn are taken from Chung et al. (1988). The reduced dipole moment is given by:
in which \(p\) is the (dimensionful) dipole moment and \(K\) is a constant with value \(131.3\;\sqrt{(\text{g}/\text{mol})\text{K}}/\text{debye}\).
The collision integral is specific for the property of viscosity (e.g., there is a different collision integral for diffusivity calculations) and is given in terms of dimensionless temperature. For the purpose of this correlation, the dimensionless temperature used is a scaled version of the reduced temperature:
in which \(T_c\) is the critical temperature. Callbacks for the collision integral are described here.
List of Parameters#
Parameter Name |
Description |
Units |
---|---|---|
|
Molecular weight \(M\) |
Mass/Amount |
|
Critical Temperature \(T_c\) |
Temperature |
|
Inverse critical molar volume \(1/V_c\) |
Amount/Volume |
|
Acentric factor \(\omega\) |
Dimensionless |
|
Molecular dipole moment \(p\) |
Charge/Length |
|
Association factor \(\kappa\) |
Dimensionless |
|
Callback to use for viscosity integral |
n/a |
Example#
The code snippet below demonstrates how to specify use of the ChungViscosityPure
model for pure component vapor viscosity as part of the modular property
framework. Note that if you specify visc_d_phase_comp
for one phase, you must specify it for all phases, even if only to pass None
as the
method.
from idaes.models.properties.modular_properties.pure import ChungViscosityPure
from idaes.models.properties.modular_properties.pure.ChapmanEnskog import collision_integral_neufeld_callback, collision_integral_kim_ross_callback
configuration = {
"components":{
"H2O": {
"type": Component,
"valid_phase_types": [PhaseType.vaporPhase, PhaseType.liquidPhase],
...
"visc_d_phase_comp": {"Vap": ChungViscosityPure, "Liq": None},
"viscosity_collision_integral_callback": collision_integral_neufeld_callback,
"parameter_data": {
"mw": (0.01801528, pyunits.kg / pyunits.mol),
"temperature_crit": (647.3, pyunits.K),
"dens_mol_crit": (0.01787, pyunits.mol/pyunits.mL),
"omega": 0.344,
"dipole_moment": (1.8546, pyunits.debye),
"association_factor_chung": 0.076
}
...
}
...
}
...
}
References#
Poling, Bruce, E. et al. The Properties of Gases and Liquids. 5th ed. New York: NcGraw-Hill, 2001.
Chung, Ting Horng, et al. “Generalized multiparameter correlation for nonpolar and polar fluid transport properties.” Industrial & Engineering Chemistry Research 27.4 (1988): 671-679.