T H E R M O D Y N A M I C S

Density

The default Density (SI unit: kg/m3) uses values From material. If User defined is selected, enter another value or expression.

Heat Capacity

The specific heat capacity Cp,p describes the amount of heat energy required to produce a unit temperature change in a unit mass of the solid material. The default setting is to use the heat capacity of the material. Select User defined to enter another value for the specific heat capacity (SI unit: J/(kg·K)).

The equivalent volumetric heat capacity of the solid-liquid system is calculated from

Cp eq = p pCp p + L Cp

Heat Transfer in Fluids

D O M A I N S E L E C T I O N

From the Selection list, choose the domains to define the heat transfer.

M O D E L I N P U T S

If user-defined property groups are added, this section displays fields and values that are inputs to expressions that define material properties.

There are also two standard model inputs—Absolute pressure and Velocity field.

The absolute pressure is used in some results analysis quantities that include the enthalpy (the energy flux, for example). It is also used if the ideal gas law is applied.

Enter the Absolute pressure p (SI unit: Pa). The default is atmosphere pressure (101,325 Pa).

From the Velocity field list, select an existing velocity field in the model (for example,

Velocity field (spf/fp1) from a Laminar Flow interface) or select User defined to enter values or expressions for the components of the Velocity field (SI unit: m/s).

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H E A T C O N D U C T I O N

The default uses the Thermal conductivity k (SI unit: W/(m·K)) From material. If User defined is selected, choose Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the thermal conductivity and enter another value or expression in the field or matrix. The thermal conductivity describes the relationship between the heat flux vector q and the temperature gradient T as in q = k T which is Fourier’s law of heat conduction. Enter this quantity as power per length and temperature.

T H E R M O D Y N A M I C S

The defaults take values From material for the Density (SI unit: kg/m3), Heat capacity at constant pressure CP (SI unit: J/(kg·K)), and the Ratio of specific heats (unitless) for a general gas or liquid. Select User defined to enter other values.

Select a Fluid type—Gas/liquid or Ideal gas:

•Select Gas/liquid to specify the density, the heat capacity at constant pressure, and the ratio of specific heats for a general gas or liquid. The default settings are to use data from the material. Select User defined to enter another value for the density, heat capacity, or ratio of specific heats.

•Select Ideal gas to use the ideal gas law to describe the fluid. In this case, specify the thermodynamics properties by selecting a gas constant type and selecting between entering the heat capacity at constant pressure or the ration of specific heats:

From the list under Gas constant type, select Specific gas constant to specify the

specific gas constant Rs, or select Mean molar mass to specify the mean molar mass

Mn. If Mean molar mass is selected, the software uses the universal gas constant

R 8.314 J/(mol·K), which is a built-in physical constant. For both properties, the default setting is to use the property value from the material. Select User defined to define another value for either of these material properties.

From the list under Specify Cp or , select Heat capacity at constant pressure to specify

the heat capacity at constant pressure Cp, or select Ratio of specific heats to specify the ratio of specific heats . For both properties, the default setting is to use the

property value from the material. Select User defined to define another value for either of these material properties.

For an ideal gas, choose to specify either Cp or the ratio of specific heats, , but not both since these, in that case, are dependent.

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