Compressible single phase fluid model¶

Overview¶

This model represents a compressible single-phase fluid with constant compressibility and pressure-dependent viscosity. These assumptions are valid for slightly compressible fluids, such as water, and some types of oil with negligible amounts of dissolved gas.

Specifically, fluid density is computed as

$\rho(p) = \rho_0 e^{c_\rho(p - p_0)}$

where $c_\rho$ is compressibility, $p_0$ is reference pressure, $\rho_0$ is density at reference pressure. Similarly,

$\mu(p) = \mu_0 e^{c_\mu(p - p_0)}$

where $c_\mu$ is viscosibility (viscosity compressibility), $\mu_0$ is reference viscosity.

Either exponent may be approximated by linear (default) or quadratic terms of Taylor series expansion. Currently there is no temperature dependence in the model, although it may be added in future.

Parameters¶

The model is represented by <CompressibleSinglePhaseFluid> node in the input.

The following attributes are supported:

Name	Type	Default	Description
compressibility	real64	0	Fluid compressibility
defaultDensity	real64	required	Default value for density.
defaultViscosity	real64	required	Default value for viscosity.
densityModelType	geosx_constitutive_ExponentApproximationType	linear	Type of density model. Valid options: * exponential * linear * quadratic
name	string	required	A name is required for any non-unique nodes
referenceDensity	real64	1000	Reference fluid density
referencePressure	real64	0	Reference pressure
referenceViscosity	real64	0.001	Reference fluid viscosity
viscosibility	real64	0	Fluid viscosity exponential coefficient
viscosityModelType	geosx_constitutive_ExponentApproximationType	linear	Type of viscosity model. Valid options: * exponential * linear * quadratic

Example¶

<Constitutive>
  <CompressibleSinglePhaseFluid name="water"
                                referencePressure="2.125e6"
                                referenceDensity="1000"
                                compressibility="1e-19"
                                referenceViscosity="0.001"
                                viscosibility="0.0"/>
</Constitutive>