Wilke Method for Low-pressure Gas Mixture Viscosity#
The ViscosityWilke
mixture gas dynamic viscosity model can be imported from idaes.models.properties.modular_properties.transport_properties
,
while additional rules and utility functions can be imported from idaes.models.properties.modular_properties.transport_properties.viscosity_wilke
.
Formulation#
This description of the Wilke method to calculate gas mixture viscosity is derived from that in The Properties of Gases and Liquids, Section 9-5. Viscosity is given by the formula
in which \(\mu_m\) is the mixture dynamic viscosity, \(\mu_i\) is the pure component viscosity of component \(i\), \(y_i\) is the gas mole fraction of component \(i\), and \(\phi_{ij}\) is a mixing function defined below.
Callbacks for Mixing Function#
These callbacks provide expressions for the mixing function \(\phi_{ij}\).
- idaes.models.properties.modular_properties.transport_properties.viscosity_wilke.wilke_phi_ij_callback(b, i, j, pname, mw_dict)[source]#
Equation 9.5.14 from Properties of Gases and Liquids.
\[\phi_{ij} = \frac{[1 + (\mu_i/\mu_j)^{1/2}(M_j/M_i)^{1/4}]^2}{[8(1+M_i/M_j)]^{1/2}}\]in which \(M_i\) is the molecular weight of component \(i\).
- idaes.models.properties.modular_properties.transport_properties.viscosity_wilke.herring_zimmer_phi_ij_callback(b, i, j, pname, mw_dict)[source]#
Equation 9.5.17 from Properties of Gases and Liquids.
\[\phi_{ij} = \left(\frac{M_j}{M_i}\right)^{1/2}\]in which \(M_i\) is the molecular weight of component \(i\).
List of Parameters#
Parameter Name |
Description |
Units |
---|---|---|
|
Molecular weight \(M_i\) |
Mass/Amount |
|
Pure component viscosity \(\mu_i\) |
Pressure*Time |
|
Callback to use for \(\phi_{ij}\) |
n/a |
Example#
The code snippet below demonstrates how to specify use of the ViscosityWilke
model for pure component vapor viscosity as part of the modular property
framework.
from idaes.models.properties.modular_properties.pure import ChapmanEnskogLennardJones
from idaes.models.properties.modular_properties.transport_properties import ViscosityWilke
from idaes.models.properties.modular_properties.transport_properties.viscosity_wilke import wilke_phi_ij_callback, herring_zimmer_phi_ij_callback
configuration = {
"components":{
"H2O": {
"type": Component,
"valid_phase_types": [PhaseType.vaporPhase],
...
"visc_d_phase_comp": {"Vap": ChapmanEnskogLennardJones}
...
}
"H2": {
"type": Component,
"valid_phase_types": [PhaseType.vaporPhase],
...
"visc_d_phase_comp": {"Vap": ChapmanEnskogLennardJones}
...
}
}
"phases":{
"Vap": {
"type": VaporPhase,
...
"visc_d_phase": ViscosityWilke,
"transport_property_options": {
"viscosity_phi_ij_callback": wilke_phi_ij_callback,
}
},
...
}
...
}
References#
Poling, Bruce, E. et al. The Properties of Gases and Liquids. 5th ed. New York: NcGraw-Hill, 2001.