Viscosity Models
This section describes the parameters for properly enabling various viscosity models.
- The aeration-viscosity coupling has been deprecated as practical use of these models was not viable (need for model calibration, lack of manufacturer specifications).
- The existing temperature-viscosity coupling model commands have changed format and are now incorporated into the new viscosity models section.
- Cross model non-Newtonian fluids are now available in nanoFluidX, also conveniently associated with the viscosity model section.
- If these simulation parameters are kept false, then the standard dynamic viscosity definition in the Phases Parameters takes precedence.
- If either varvisc_temperature or varvisc_non_Newtonian are enabled (set to true), and a fluid phase is missed in the Viscosity Models section - the missed fluid will be assumed Newtonian and the standard dynamic viscosity definition from the Phase Parameters is assumed. It is best practice that if either varvisc_temperature or varvisc_non_Newtonian are enabled, you proceed using the Viscosity Models section for definition of all phase viscosity models.
For more information about viscosity models, refer to Viscosity Models in the Theory Manual.
Commands
viscosityModels
{
viscosityModel
{
viscosityModel_type FLUID_NEWTONIAN
viscosityModel_phase 1
viscosityModel_visc 1e-3
}
viscosityModel
{
viscosityModel_type FLUID_S_CROSS
viscosityModel_phase 3
viscosityModel_k 1.0
viscosityModel_n 0
viscosityModel_visc_0 1e-3
viscosityModel_visc_inf 1e-3
}
viscosityModel
{
viscosityModel_type FLUID_T_POLYNOMIAL
viscosityModel_phase 4
viscosityModel_c "1e-3 0.0 0.0 0.0 0.0"
}
viscosityModel
{
viscosityModel_type FLUID_T_SUTHERLAND
viscosityModel_phase 5
viscosityModel_visc_ref 1.716e-5
viscosityModel_temp_ref 273.15
viscosityModel_temp_sut 110.4
}
viscosityModel
{
viscosityModel_type FLUID_T_POWER_LAW
viscosityModel_phase 6
viscosityModel_visc_ref 1e-3
viscosityModel_temp_ref 273.15
viscosityModel_n 0
}
}
Definitions
Command | Contents | SI Unit Example |
---|---|---|
viscosityModel_type | Viscosity model choice which will be assigned to the
respective fluid phase (viscosityModel_phase) Options
Attention: Only one model can be selected
per phase.
|
|
viscosityModel_phase | Phase ID of the fluid phase which is affected by the selected model choice. | |
viscosityModel_visc | Dynamic viscosity when using the Newtonian fluid
model. Default = 0.001 |
[Pa.s] |
viscosityModel_k | Dimensionless coefficient k for the Cross model (see Viscosity Models for more
information). Default = 0.001 |
|
viscosityModel_n | Serves as a dimensionless power exponent in the Cross model
for non-Newtonian viscosity and Power Law temperature dependence
model (see Viscosity Models for
more information). Default = 0.0 |
|
viscosityModel_visc_0 | Zero shear rate viscosity for the Cross model. Default = 0.001 |
[Pa.s] |
viscosityModel_visc_inf | Infinite shear rate viscosity for the Cross model. Default = 0.001 |
[Pa.s] |
viscosityModel_c | Coefficients for the temperature-viscosity polynomial model.
This is a vector variable, comprising of 5 values defined in
order of the polynomial. Default = "0.001 0.0 0.0 0.0 0.0" |
[Pa.s, Pa.s/T, Pa.s/T2, Pa.s/T3, Pa.s/T4] |
viscosityModel_temp_ref | Base temperature of the Sutherland temperature-viscosity
dependence model. Default = 273.15 |
[K] |
viscosityModel_visc_ref | Base viscosity of Sutherland temperature-viscosity dependence
model. Default = 0.00001716 |
[Pa.s] |
viscosityModel_sut | Sutherland temperature (also known as Sutherland's
coefficient). Default = 110.4 |
[K] |