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Added member to TransportBase to allow specification of the reference

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velocity.  This allows selection of a mass-averaged, mole-averaged or
solvent specified reference velocity using the member m_velocityBasis
or the methods setVelocityBasis() and getVelocityBasis().  Parsing of
input needs to  be added for this still.  An enum has been added 
  enum VelocityBasis {
    VB_MOLEAVG = -2,
    VB_MASSAVG = -1  };
Other values can correspond to species indices.

In LiquidTransport, the Stefan Maxwell solve now checks to see what
the m_velocityBasis member says the reference velocity should be and
fills the matrix accordingly.  To allow mass averaged we have added
members m_massfracs and m_massfracs_tran.  

Added methods to extract the diffusion velocity in a similar manner to
the diffusive fluxes.  The diffusion velocity will be needed to not
force the porosity/tortuosity into the Transport classes for
porous flow.  These methods are getSpeciesVdiff() and
getSpeciesVdiffES().
This commit is contained in:
John Hewson 2009-11-30 23:21:19 +00:00
parent 36c19bd3a1
commit 4cee810c18
4 changed files with 274 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

115
Cantera/src/transport/LiquidTransport.cpp
View file

@ -117,6 +117,8 @@ namespace Cantera {
m_lambdaMixModel = right.m_lambdaMixModel;
m_diffMixModel = right.m_diffMixModel;
m_iStateMF = -1;
m_massfracs = right.m_massfracs;
m_massfracs_tran = right.m_massfracs_tran;
m_molefracs = right.m_molefracs;
m_molefracs_tran = right.m_molefracs_tran;
m_concentrations = right.m_concentrations;
@ -267,6 +269,8 @@ namespace Cantera {
m_mode = tr.mode_;
m_massfracs.resize(m_nsp);
m_massfracs_tran.resize(m_nsp);
m_molefracs.resize(m_nsp);
m_molefracs_tran.resize(m_nsp);
m_concentrations.resize(m_nsp);
@ -510,6 +514,48 @@ namespace Cantera {
}
}
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
* @param ldx Leading dimension of the grad_X array.
* The diffusive mass flux of species \e k is computed from
*
* \f[
* \vec{j}_k = -n M_k D_k \nabla X_k.
* \f]
*/
void LiquidTransport::getSpeciesVdiff(int ndim,
const doublereal* grad_T,
int ldx, const doublereal* grad_X,
int ldf, doublereal* Vdiff) {
set_Grad_T(grad_T);
set_Grad_X(grad_X);
getSpeciesVdiffExt(ldf, Vdiff);
}
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
* @param ldx Leading dimension of the grad_X array.
* The diffusive mass flux of species \e k is computed from
*
* \f[
* \vec{j}_k = -n M_k D_k \nabla X_k.
* \f]
*/
void LiquidTransport::getSpeciesVdiffES(int ndim,
const doublereal* grad_T,
int ldx,
const doublereal* grad_X,
int ldf,
const doublereal* grad_V,
doublereal* Vdiff) {
set_Grad_T(grad_T);
set_Grad_X(grad_X);
set_Grad_V(grad_V);
getSpeciesVdiffExt(ldf, Vdiff);
}
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
@ -552,6 +598,33 @@ namespace Cantera {
getSpeciesFluxesExt(ldf, fluxes);
}
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
* @param ldx Leading dimension of the grad_X array.
* The diffusive mass flux of species \e k is computed from
*
* \f[
* \vec{j}_k = -n M_k D_k \nabla X_k.
* \f]
*/
void LiquidTransport::getSpeciesVdiffExt(int ldf, doublereal* Vdiff) {
int n, k;
update_T();
update_C();
update_Grad_lnAC();
stefan_maxwell_solve();
for (n = 0; n < m_nDim; n++) {
for (k = 0; k < m_nsp; k++) {
Vdiff[n*ldf + k] = m_Vdiff(k,n);
}
}
}
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
@ -577,7 +650,6 @@ namespace Cantera {
fluxes[n*ldf + k] = m_flux(k,n);
}
}
/*
getMixDiffCoeffs(DATA_PTR(m_spwork));
const array_fp& mw = m_thermo->molecularWeights();
@ -716,6 +788,7 @@ namespace Cantera {
int iStateNew = m_thermo->stateMFNumber();
if (iStateNew != m_iStateMF) {
qReturn = false;
m_thermo->getMassFractions(DATA_PTR(m_massfracs));
m_thermo->getMoleFractions(DATA_PTR(m_molefracs));
m_thermo->getConcentrations(DATA_PTR(m_concentrations));
concTot_ = 0.0;
@ -723,6 +796,7 @@ namespace Cantera {
for (int k = 0; k < m_nsp; k++) {
m_molefracs[k] = fmaxx(0.0, m_molefracs[k]);
m_molefracs_tran[k] = fmaxx(MIN_X, m_molefracs[k]);
m_massfracs_tran[k] = fmaxx(MIN_X, m_massfracs[k]);
concTot_tran_ += m_molefracs_tran[k];
concTot_ += m_concentrations[k];
}
@ -1000,8 +1074,19 @@ namespace Cantera {
switch (m_nDim) {
case 1: /* 1-D approximation */
m_B(0,0) = 0.0;
//equation for the reference velocity
for (j = 0; j < m_nsp; j++) {
m_A(0,j) = m_molefracs_tran[j];
if ( m_velocityBasis == VB_MOLEAVG )
m_A(0,j) = m_molefracs_tran[j];
else if ( m_velocityBasis == VB_MASSAVG )
m_A(0,j) = m_massfracs_tran[j];
else if ( ( m_velocityBasis >= 0 )
&& ( m_velocityBasis < m_nsp ) )
// use species number m_velocityBasis as reference velocity
if ( m_velocityBasis == j ) m_A(0,j) = 1.0;
else
throw CanteraError("LiquidTransport::stefan_maxwell_solve",
"Unknown reference velocity provided.");
}
for (i = 1; i < m_nsp; i++){
m_B(i,0) = m_Grad_mu[i] / (GasConstant * T);
@ -1025,8 +1110,19 @@ namespace Cantera {
case 2: /* 2-D approximation */
m_B(0,0) = 0.0;
m_B(0,1) = 0.0;
//equation for the reference velocity
for (j = 0; j < m_nsp; j++) {
m_A(0,j) = m_molefracs_tran[j];
if ( m_velocityBasis == VB_MOLEAVG )
m_A(0,j) = m_molefracs_tran[j];
else if ( m_velocityBasis == VB_MASSAVG )
m_A(0,j) = m_massfracs_tran[j];
else if ( ( m_velocityBasis >= 0 )
&& ( m_velocityBasis < m_nsp ) )
// use species number m_velocityBasis as reference velocity
if ( m_velocityBasis == j ) m_A(0,j) = 1.0;
else
throw CanteraError("LiquidTransport::stefan_maxwell_solve",
"Unknown reference velocity provided.");
}
for (i = 1; i < m_nsp; i++){
m_B(i,0) = m_Grad_mu[i] / (GasConstant * T);
@ -1054,8 +1150,19 @@ namespace Cantera {
m_B(0,0) = 0.0;
m_B(0,1) = 0.0;
m_B(0,2) = 0.0;
//equation for the reference velocity
for (j = 0; j < m_nsp; j++) {
m_A(0,j) = m_molefracs_tran[j];
if ( m_velocityBasis == VB_MOLEAVG )
m_A(0,j) = m_molefracs_tran[j];
else if ( m_velocityBasis == VB_MASSAVG )
m_A(0,j) = m_massfracs_tran[j];
else if ( ( m_velocityBasis >= 0 )
&& ( m_velocityBasis < m_nsp ) )
// use species number m_velocityBasis as reference velocity
if ( m_velocityBasis == j ) m_A(0,j) = 1.0;
else
throw CanteraError("LiquidTransport::stefan_maxwell_solve",
"Unknown reference velocity provided.");
}
for (i = 1; i < m_nsp; i++){
m_B(i,0) = m_Grad_mu[i] / (GasConstant * T);

78
Cantera/src/transport/LiquidTransport.h
View file

@ -334,6 +334,64 @@ namespace Cantera {
*/
virtual void update_Grad_lnAC();
//! Get the species diffusive velocities wrt to
//! the mass averaged velocity,
//! given the gradients in mole fraction and temperature
/*!
* Units for the returned fluxes are kg m-2 s-1.
*
* @param ndim Number of dimensions in the flux expressions
* @param grad_T Gradient of the temperature
* (length = ndim)
* @param ldx Leading dimension of the grad_X array
* (usually equal to m_nsp but not always)
* @param grad_X Gradients of the mole fraction
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
* @param ldf Leading dimension of the fluxes array
* (usually equal to m_nsp but not always)
* @param Vdiff Output of the diffusive velocities.
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
*/
virtual void getSpeciesVdiff(int ndim,
const doublereal* grad_T,
int ldx,
const doublereal* grad_X,
int ldf,
doublereal* Vdiff) ;
//! Get the species diffusive mass fluxes wrt to
//! the mass averaged velocity,
//! given the gradients in mole fraction, temperature
//! and electrostatic potential.
/*!
* Units for the returned fluxes are kg m-2 s-1.
*
* @param ndim Number of dimensions in the flux expressions
* @param grad_T Gradient of the temperature
* (length = ndim)
* @param ldx Leading dimension of the grad_X array
* (usually equal to m_nsp but not always)
* @param grad_X Gradients of the mole fraction
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
* @param ldf Leading dimension of the fluxes array
* (usually equal to m_nsp but not always)
* @param grad_Phi Gradients of the electrostatic potential
* (length = ndim)
* @param fluxes Output of the diffusive mass fluxes
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
*/
virtual void getSpeciesVdiffES(int ndim,
const doublereal* grad_T,
int ldx,
const doublereal* grad_X,
int ldf,
const doublereal* grad_Phi,
doublereal* Vdiff) ;
/**
* @param ndim The number of spatial dimensions (1, 2, or 3).
* @param grad_T The temperature gradient (ignored in this model).
@ -391,6 +449,11 @@ namespace Cantera {
const doublereal* grad_Phi,
doublereal* fluxes);
//! Return the species diffusive velocities relative to
//! the (mass) averaged velocity.
//! See getSpeciesFluxesExt for further details.
virtual void getSpeciesVdiffExt(int ldf, doublereal* Vdiff);
//! Return the species diffusive mass fluxes wrt to
//! the mass averaged velocity,
/*!
@ -736,6 +799,21 @@ namespace Cantera {
//! State of the mole fraction vector.
int m_iStateMF;
//! Local copy of the mass fractions of the species in the phase
/*!
* The mass fraction vector comes from the ThermoPhase object.
*
* length = m_nsp
*/
vector_fp m_massfracs;
//! Local copy of the mass fractions of the species in the phase
/**
* This version of the mass fraction vector is adjusted to a
* minimum lower bound of MIN_X for use in transport calculations.
*/
vector_fp m_massfracs_tran;
//! Local copy of the mole fractions of the species in the phase
/*!
* The mole fractions here are assumed to be bounded by 0.0 and 1.0

5
Cantera/src/transport/TransportBase.cpp
View file

@ -38,7 +38,8 @@ namespace Cantera {
m_ready(false),
m_nmin(0),
m_index(-1),
m_nDim(ndim)
m_nDim(ndim),
m_velocityBasis(VB_MASSAVG)
{
}
@ -49,6 +50,7 @@ namespace Cantera {
m_nmin = right.m_nmin;
m_index = right.m_index;
m_nDim = right.m_nDim;
m_velocityBasis = right.m_velocityBasis;
}
@ -61,6 +63,7 @@ namespace Cantera {
m_nmin = right.m_nmin;
m_index = right.m_index;
m_nDim = right.m_nDim;
m_velocityBasis = right.m_velocityBasis;
return *this;
}

81
Cantera/src/transport/TransportBase.h
View file

@ -56,6 +56,17 @@ namespace Cantera {
// forward reference
class XML_Writer;
/** The diffusion velocities can be referenced to a variety of things.
* Most typical is to reference to the mass averaged velocity, but
* referencing to the mole averaged velocity is suitable for some
* liquid flows and referencing to a single species is suitable for
* some solvent mixtures. This enum should provide a means to identify
* the reference velocity used for the transport model.
*/
enum VelocityBasis {
VB_MOLEAVG = -2,
VB_MASSAVG = -1
};
/**
* Base class for transport property managers. All classes that
@ -306,6 +317,69 @@ namespace Cantera {
}
//! Get the species diffusive velocities wrt to
//! the mass averaged velocity,
//! given the gradients in mole fraction and temperature
/*!
* Units for the returned fluxes are kg m-2 s-1.
*
* @param ndim Number of dimensions in the flux expressions
* @param grad_T Gradient of the temperature
* (length = ndim)
* @param ldx Leading dimension of the grad_X array
* (usually equal to m_nsp but not always)
* @param grad_X Gradients of the mole fraction
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
* @param ldf Leading dimension of the fluxes array
* (usually equal to m_nsp but not always)
* @param Vdiff Output of the diffusive velocities.
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
*/
virtual void getSpeciesVdiff(int ndim,
const doublereal* grad_T,
int ldx,
const doublereal* grad_X,
int ldf,
doublereal* Vdiff) {
err("getSpeciesVdiff");
}
//! Get the species diffusive mass fluxes wrt to
//! the mass averaged velocity,
//! given the gradients in mole fraction, temperature
//! and electrostatic potential.
/*!
* Units for the returned fluxes are kg m-2 s-1.
*
* @param ndim Number of dimensions in the flux expressions
* @param grad_T Gradient of the temperature
* (length = ndim)
* @param ldx Leading dimension of the grad_X array
* (usually equal to m_nsp but not always)
* @param grad_X Gradients of the mole fraction
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
* @param ldf Leading dimension of the fluxes array
* (usually equal to m_nsp but not always)
* @param grad_Phi Gradients of the electrostatic potential
* (length = ndim)
* @param fluxes Output of the diffusive mass fluxes
* Flat vector with the m_nsp in the inner loop.
* length = ldx * ndim
*/
virtual void getSpeciesVdiffES(int ndim,
const doublereal* grad_T,
int ldx,
const doublereal* grad_X,
int ldf,
const doublereal* grad_Phi,
doublereal* Vdiff) {
getSpeciesVdiff( ndim, grad_T, ldx, grad_X, ldf, Vdiff );
}
//! Get the molar fluxes [kmol/m^2/s], given the thermodynamic
//! state at two nearby points.
/*!
@ -390,6 +464,10 @@ namespace Cantera {
const doublereal* const p);
void setVelocityBasis( int ivb ) { m_velocityBasis = ivb; }
int getVelocityBasis( ) { return m_velocityBasis; }
friend class TransportFactory;
@ -447,6 +525,9 @@ namespace Cantera {
//! Number of dimensions used in flux expresions
int m_nDim;
//! velocity basis from which diffusion velocities are computed.
//! Defaults to mass averaged = -2
int m_velocityBasis;
private: