Fluid Expansion

The thermal expansion coefficients are interpreted as total expansion coefficients from a reference temperature, which can be specified as a function of temperature or predefined field variables. The change in fluid volume as a result of thermal expansion is determined as follows:

V_{0} (θ) = V_{0} (θ_{I}) [1 + 3 α (θ) (θ - θ_{0}) - 3 α (θ_{I}) (θ_{I} - θ_{0})],

where $θ_{0}$ is the reference temperature for the coefficient of thermal expansion and $α (θ)$ is the mean (secant) coefficient of thermal expansion.

If the coefficient of thermal expansion is not a function of temperature or field variables, the value of $θ_{0}$ is not needed.

You can also express thermal fluid expansion in terms of the fluid density:

ρ_{0} (θ) = ρ_{R} / [1 + 3 α (θ) (θ - θ_{0}) - 3 α (θ_{I}) (θ_{I} - θ_{0})],

Parameters


Input Data	Description
Reference temperature	Reference temperature for the coefficient of thermal expanion, $θ_{0}$ .
Use temperature-dependent data	Specifies material parameters that depend on temperature. A Temperature field appears in the data table. For more information, see Specifying Material Data as a Function of Temperature and Independent Field Variables.
Number of field variables	Specifies material parameters that depend on field variables. Field columns appear in the data table for each field variable you add. For more information, see Specifying Material Data as a Function of Temperature and Independent Field Variables.
Thermal expansion coefficient	Constant value that describes how much the material expands with increases in temperature.