Compositional Multi-Phase Model Using Primary Variable Switching. More...
Classes | |
class | Ewoms::PvsBoundaryRateVector< TypeTag > |
Implements a rate vector on the boundary for the fully implicit compositional multi-phase primary variable switching compositional model. More... | |
class | Ewoms::PvsExtensiveQuantities< TypeTag > |
Contains all data which is required to calculate all fluxes at a flux integration point for the primary variable switching model. More... | |
class | Ewoms::PvsIndices< TypeTag, PVOffset > |
The indices for the compositional multi-phase primary variable switching model. More... | |
class | Ewoms::PvsIntensiveQuantities< TypeTag > |
Contains the quantities which are are constant within a finite volume in the compositional multi-phase primary variable switching model. More... | |
class | Ewoms::PvsLocalResidual< TypeTag > |
Element-wise calculation of the local residual for the compositional multi-phase primary variable switching model. More... | |
class | Ewoms::PvsModel< TypeTag > |
A generic compositional multi-phase model using primary-variable switching. More... | |
class | Ewoms::PvsNewtonMethod< TypeTag > |
A newton solver which is specific to the compositional multi-phase PVS model. More... | |
class | Ewoms::PvsPrimaryVariables< TypeTag > |
Represents the primary variables used in the primary variable switching compositional model. More... | |
class | Ewoms::PvsRateVector< TypeTag > |
Implements a vector representing molar, mass or volumetric rates. More... | |
Compositional Multi-Phase Model Using Primary Variable Switching.
This model assumes a flow of fluid phases
, each of which is assumed to be a mixture
chemical species
.
By default, the standard multi-phase Darcy approach is used to determine the velocity, i.e.
although the actual approach which is used can be specified via the FluxModule
property. For example, the velocity model can by changed to the Forchheimer approach by
The core of the model is the conservation mass of each component by means of the equation
To close the system mathematically, model equations are also required. This model uses the primary variable switching assumptions, which are given by:
To make this approach applicable, a pseudo primary variable phase presence has to be introduced. Its purpose is to specify for each phase whether it is present or not. It is a pseudo primary variable because it is not directly considered when linearizing the system in the Newton method, but after each Newton iteration, it gets updated like the "real" primary variables. The following rules are used for this update procedure:
In all other cases don't modify the phase presence for phase .
The model always requires primary variables, but their interpretation is dependent on the phase presence:
The first primary variable is always interpreted as the pressure of the phase with the lowest index .
Then, "switching primary variables" follow, which are interpreted depending in the presence of the first
phases: If phase
is present, its saturation
is used as primary variable; if it is not present, the mole fraction
of the component with index
in the phase with the lowest index that is present
is used instead.
Finally, the mole fractions of the components with the largest index in the phase with the lowest index that is present
are used as primary variables.