A compositional multi-phase model based on non-linear complementarity functions. More...

#include <ncpmodel.hh>

Inheritance diagram for Ewoms::NcpModel< TypeTag >:
Inheritance graph

Public Member Functions

 NcpModel (Simulator &simulator)
 
void finishInit ()
 Apply the initial conditions to the model. More...
 
std::string primaryVarName (int pvIdx) const
 Given an primary variable index, return a human readable name. More...
 
std::string eqName (int eqIdx) const
 Given an equation index, return a human readable name. More...
 
void updateBegin ()
 Called by the update() method before it tries to apply the newton method. This is primary a hook which the actual model can overload. More...
 
void updatePVWeights (const ElementContext &elemCtx) const
 Update the weights of all primary variables within an element given the complete set of intensive quantities. More...
 
Scalar primaryVarWeight (int globalDofIdx, int pvIdx) const
 Returns the relative weight of a primary variable for calculating relative errors. More...
 
Scalar eqWeight (int globalDofIdx, int eqIdx) const
 Returns the relative weight of an equation. More...
 
Scalar minActivityCoeff (int globalDofIdx, int compIdx) const
 Returns the smallest activity coefficient of a component for the most current solution at a vertex. More...
 
void registerOutputModules_ ()
 
bool phaseIsConsidered (int phaseIdx) const
 Returns true iff a fluid phase is used by the model. More...
 
void globalPhaseStorage (EqVector &storage, int phaseIdx)
 Compute the total storage inside one phase of all conservation quantities. More...
 

Static Public Member Functions

static void registerParameters ()
 Register all run-time parameters for the immiscible model. More...
 
static std::string name ()
 

Public Attributes

Scalar referencePressure_
 
std::vector< ComponentVector > minActivityCoeff_
 

Detailed Description

template<class TypeTag>
class Ewoms::NcpModel< TypeTag >

A compositional multi-phase model based on non-linear complementarity functions.

This model implements a $M$-phase flow of a fluid mixture composed of $N$ chemical species. The phases are denoted by lower index $\alpha \in \{ 1, \dots, M \}$. All fluid phases are mixtures of $N \geq M - 1$ chemical species which are denoted by the upper index $\kappa \in \{ 1, \dots, N \} $.

By default, the standard multi-phase Darcy approach is used to determine the velocity, i.e.

\[ \mathbf{v}_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left(\mathbf{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right) \;, \]

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

\[ \sum_\alpha \frac{\partial\;\phi c_\alpha^\kappa S_\alpha }{\partial t} - \sum_\alpha \mathrm{div} \left\{ c_\alpha^\kappa \mathbf{v}_\alpha \right\} - q^\kappa = 0 \;. \]

For the missing $M$ model assumptions, the model uses non-linear complementarity functions. These are based on the observation that if a fluid phase is not present, the sum of the mole fractions of this fluid phase is smaller than $1$, i.e.

\[ \forall \alpha: S_\alpha = 0 \implies \sum_\kappa x_\alpha^\kappa \leq 1 \]

Also, if a fluid phase may be present at a given spatial location its saturation must be non-negative:

\[ \forall \alpha: \sum_\kappa x_\alpha^\kappa = 1 \implies S_\alpha \geq 0 *\]

Since at any given spatial location, a phase is always either present or not present, one of the strict equalities on the right hand side is always true, i.e.

\[ \forall \alpha: S_\alpha \left( \sum_\kappa x_\alpha^\kappa - 1 \right) = 0 \]

always holds.

These three equations constitute a non-linear complementarity problem, which can be solved using so-called non-linear complementarity functions $\Phi(a, b)$. Such functions have the property

\[\Phi(a,b) = 0 \iff a \geq0 \land b \geq0 \land a \cdot b = 0 \]

Several non-linear complementarity functions have been suggested, e.g. the Fischer-Burmeister function

\[ \Phi(a,b) = a + b - \sqrt{a^2 + b^2} \;. \]

This model uses

\[ \Phi(a,b) = \min \{a, b \}\;, \]

because of its piecewise linearity.

The model assumes local thermodynamic equilibrium and uses the following primary variables:

  • The pressure of the first phase $p_1$
  • The component fugacities $f^1, \dots, f^{N}$
  • The saturations of the first $M-1$ phases $S_1, \dots, S_{M-1}$
  • Temperature $T$ if the energy equation is enabled

Constructor & Destructor Documentation

template<class TypeTag >
Ewoms::NcpModel< TypeTag >::NcpModel ( Simulator simulator)
inline

Member Function Documentation

template<class TypeTag >
std::string Ewoms::NcpModel< TypeTag >::eqName ( int  eqIdx) const
inline

Given an equation index, return a human readable name.

Parameters
eqIdxThe index of the conservation equation of interest.
template<class TypeTag >
Scalar Ewoms::NcpModel< TypeTag >::eqWeight ( int  globalDofIdx,
int  eqIdx 
) const
inline

Returns the relative weight of an equation.

Parameters
globalVertexIdxThe global index of the vertex
eqIdxThe index of the equation
template<class TypeTag >
void Ewoms::NcpModel< TypeTag >::finishInit ( )
inline
template<class TypeTag >
void Ewoms::MultiPhaseBaseModel< TypeTag >::globalPhaseStorage ( EqVector &  storage,
int  phaseIdx 
)
inlineinherited

Compute the total storage inside one phase of all conservation quantities.

Parameters
storageStores the total amount of each conserved quantity inside the domain.
phaseIdxThe index of the fluid phase of interest.

References Ewoms::ThreadedEntityIterator< GridView, codim >::beginParallel(), Ewoms::ThreadedEntityIterator< GridView, codim >::increment(), Ewoms::ThreadedEntityIterator< GridView, codim >::isFinished(), Ewoms::ThreadManager< TypeTag >::threadId(), and OmpMutex::unlock().

template<class TypeTag >
Scalar Ewoms::NcpModel< TypeTag >::minActivityCoeff ( int  globalDofIdx,
int  compIdx 
) const
inline

Returns the smallest activity coefficient of a component for the most current solution at a vertex.

Parameters
globalDofIdxThe global index of the vertex (i.e. finite volume) of interest.
compIdxThe index of the component of interest.

References Ewoms::NcpModel< TypeTag >::minActivityCoeff_.

template<class TypeTag >
static std::string Ewoms::NcpModel< TypeTag >::name ( )
inlinestatic

template<class TypeTag >
bool Ewoms::MultiPhaseBaseModel< TypeTag >::phaseIsConsidered ( int  phaseIdx) const
inlineinherited

Returns true iff a fluid phase is used by the model.

Parameters
phaseIdxThe index of the fluid phase in question
template<class TypeTag >
std::string Ewoms::NcpModel< TypeTag >::primaryVarName ( int  pvIdx) const
inline

Given an primary variable index, return a human readable name.

Parameters
pvIdxThe index of the primary variable of interest.
template<class TypeTag >
Scalar Ewoms::NcpModel< TypeTag >::primaryVarWeight ( int  globalDofIdx,
int  pvIdx 
) const
inline

Returns the relative weight of a primary variable for calculating relative errors.

Parameters
globalDofIdxThe global index of the degree of freedom
pvIdxThe index of the primary variable

References GET_PROP_VALUE, Ewoms::NcpModel< TypeTag >::minActivityCoeff_, and Ewoms::NcpModel< TypeTag >::referencePressure_.

template<class TypeTag >
void Ewoms::NcpModel< TypeTag >::registerOutputModules_ ( )
inline
template<class TypeTag >
static void Ewoms::NcpModel< TypeTag >::registerParameters ( )
inlinestatic
template<class TypeTag >
void Ewoms::NcpModel< TypeTag >::updateBegin ( )
inline

Called by the update() method before it tries to apply the newton method. This is primary a hook which the actual model can overload.

References Ewoms::NcpModel< TypeTag >::referencePressure_.

template<class TypeTag >
void Ewoms::NcpModel< TypeTag >::updatePVWeights ( const ElementContext &  elemCtx) const
inline

Update the weights of all primary variables within an element given the complete set of intensive quantities.

References Ewoms::NcpModel< TypeTag >::minActivityCoeff_.

Member Data Documentation

template<class TypeTag >
Scalar Ewoms::NcpModel< TypeTag >::referencePressure_
mutable

The documentation for this class was generated from the following file: