This section is available when temperature-dependent material properties are used. By default the temperature of the parent interface is used and the section is not editable. To edit the Temperature field, click
Make All Model Inputs Editable (
). The available options are
User defined (default) and all temperature variables from the physics interfaces included in the model. These physics interfaces have their own tags (the
Name). For example, if a
Heat Transfer in Fluids interface is included in the model, the
Temperature (ht) option is available.
The default Absolute pressure pA is
User defined. When additional physics interfaces are added to the model, the absolute pressure variables defined by these physics interfaces can also be selected from the list. For example, if a
Laminar Flow interface is added you can select
Absolute pressure (spf) from the list.
The default Velocity field u is
User defined. For
User defined enter values or expressions for the components based on space dimensions. Or select an existing velocity field in the component (for example,
Velocity field (spf) from a
Laminar Flow interface).
From the Concentration c (SI unit: mol/m
3 or kg/m
3) list, select an existing concentration variable from another physics interface, if any concentration variables exist, or select
User defined to enter a value or expression for the concentration. This section can be edited anytime a material property is concentration dependent; for example, when the
Fluid type is set to
Moist air with
Input quantity set to
Concentration.
The thermal conductivity k describes the relationship between the heat flux vector
q and the temperature gradient
∇T in
q = −k∇T, which is Fourier’s law of heat conduction. Enter this quantity as power per length and temperature.
The default Thermal conductivity k is taken
From material. For
User defined select
Isotropic,
Diagonal,
Symmetric, or
Anisotropic based on the characteristics of the thermal conductivity, and enter another value or expression. For
Isotropic enter a scalar which will be used to define a diagonal tensor. For the other options, enter values or expressions into the editable fields of the tensor.
The heat capacity at constant pressure Cp describes the amount of heat energy required to produce a unit temperature change in a unit mass.
The ratio of specific heats γ is the ratio of the heat capacity at constant pressure,
Cp, to the heat capacity at constant volume,
Cv. When using the ideal gas law to describe a fluid, specifying
γ is sufficient to evaluate
Cp. For common diatomic gases such as air,
γ = 1.4 is the standard value. Most liquids have
γ = 1.1 while water has
γ = 1.0. γ is used in the streamline stabilization and in the variables for heat fluxes and total energy fluxes. It is also used if the ideal gas law is applied.
The only Fluid type option is
Gas/Liquid. This option specifies the
Density, the
Heat capacity at constant pressure, and the
Ratio of specific heats for a general gas or liquid
.
