Cantera 2.6.0

chemical equilibrium. More...
Classes  
class  MultiPhase 
A class for multiphase mixtures. More...  
class  vcs_MultiPhaseEquil 
Cantera's Interface to the Multiphase chemical equilibrium solver. More...  
Functions  
void  equilibrate (const std::string &XY, const std::string &solver="auto", double rtol=1e9, int max_steps=50000, int max_iter=100, int estimate_equil=0, int log_level=0) 
Equilibrate a MultiPhase object. More...  
size_t  BasisOptimize (int *usedZeroedSpecies, bool doFormRxn, MultiPhase *mphase, std::vector< size_t > &orderVectorSpecies, std::vector< size_t > &orderVectorElements, vector_fp &formRxnMatrix) 
Choose the optimum basis of species for the equilibrium calculations. More...  
void  ElemRearrange (size_t nComponents, const vector_fp &elementAbundances, MultiPhase *mphase, std::vector< size_t > &orderVectorSpecies, std::vector< size_t > &orderVectorElements) 
Handles the potential rearrangement of the constraint equations represented by the Formula Matrix. More...  
Chemical Equilibrium  
void  equilibrate (const std::string &XY, const std::string &solver="auto", double rtol=1e9, int max_steps=50000, int max_iter=100, int estimate_equil=0, int log_level=0) 
Equilibrate a ThermoPhase object. More...  
virtual void  setToEquilState (const doublereal *mu_RT) 
This method is used by the ChemEquil equilibrium solver. More...  
virtual bool  compatibleWithMultiPhase () const 
Indicates whether this phase type can be used with class MultiPhase for equilibrium calculations. More...  
chemical equilibrium.
void equilibrate  (  const std::string &  XY, 
const std::string &  solver = "auto" , 

double  rtol = 1e9 , 

int  max_steps = 50000 , 

int  max_iter = 100 , 

int  estimate_equil = 0 , 

int  log_level = 0 

) 
Equilibrate a MultiPhase object.
Set this mixture to chemical equilibrium by calling one of Cantera's equilibrium solvers. The XY parameter indicates what two thermodynamic quantities are to be held constant during the equilibration process.
XY  String representation of what two properties are being held constant 
solver  Name of the solver to be used to equilibrate the phase. If solver = 'vcs', the vcs_MultiPhaseEquil solver will be used. If solver = 'gibbs', the MultiPhaseEquil solver will be used. If solver = 'auto', the 'vcs' solver will be tried first, followed by the 'gibbs' solver if the first one fails. 
rtol  Relative tolerance 
max_steps  Maximum number of steps to take to find the solution 
max_iter  The maximum number of outer temperature or pressure iterations to take when T and/or P is not held fixed. 
estimate_equil  integer indicating whether the solver should estimate its own initial condition. If 0, the initial mole fraction vector in the ThermoPhase object is used as the initial condition. If 1, the initial mole fraction vector is used if the element abundances are satisfied. If 1, the initial mole fraction vector is thrown out, and an estimate is formulated. 
log_level  loglevel Controls amount of diagnostic output. log_level=0 suppresses diagnostics, and increasinglyverbose messages are written as loglevel increases. 
Definition at line 645 of file MultiPhase.cpp.
References Cantera::_equilflag(), Cantera::debuglog(), vcs_MultiPhaseEquil::equilibrate(), MultiPhase::equilibrate_MultiPhaseEquil(), MultiPhase::m_moleFractions, MultiPhase::m_moles, MultiPhase::m_press, MultiPhase::m_temp, and MultiPhase::updatePhases().
size_t BasisOptimize  (  int *  usedZeroedSpecies, 
bool  doFormRxn,  
MultiPhase *  mphase,  
std::vector< size_t > &  orderVectorSpecies,  
std::vector< size_t > &  orderVectorElements,  
vector_fp &  formRxnMatrix  
) 
Choose the optimum basis of species for the equilibrium calculations.
This is done by choosing the species with the largest mole fraction not currently a linear combination of the previous components. Then, calculate the stoichiometric coefficient matrix for that basis.
Calculates the identity of the component species in the mechanism. Rearranges the solution data to put the component data at the front of the species list.
Then, calculates SC(J,I) the formation reactions for all noncomponent species in the mechanism.
[in]  mphase  Pointer to the multiphase object. Contains the species mole fractions, which are used to pick the current optimal species component basis. 
[in]  orderVectorElements  Order vector for the elements. The element rows in the formula matrix are rearranged according to this vector. 
[in]  orderVectorSpecies  Order vector for the species. The species are rearranged according to this formula. The first nComponents of this vector contain the calculated species components on exit. 
[in]  doFormRxn  If true, the routine calculates the formation reaction matrix based on the calculated component species. If false, this step is skipped. 
[out]  usedZeroedSpecies  = If true, then a species with a zero concentration was used as a component. The problem may be converged. 
[out]  formRxnMatrix 
Definition at line 20 of file BasisOptimize.cpp.
References Cantera::BasisOptimize_print_lvl, Array2D::data(), MultiPhase::elementName(), MultiPhase::getMoles(), MultiPhase::nAtoms(), MultiPhase::nElements(), Cantera::npos, MultiPhase::nSpecies(), DenseMatrix::resize(), Cantera::solve(), MultiPhase::speciesName(), Cantera::writelog(), and Cantera::writelogf().
Referenced by ChemEquil::estimateElementPotentials().
void ElemRearrange  (  size_t  nComponents, 
const vector_fp &  elementAbundances,  
MultiPhase *  mphase,  
std::vector< size_t > &  orderVectorSpecies,  
std::vector< size_t > &  orderVectorElements  
) 
Handles the potential rearrangement of the constraint equations represented by the Formula Matrix.
Rearrangement is only necessary when the number of components is less than the number of elements. For this case, some constraints can never be satisfied exactly, because the range space represented by the Formula Matrix of the components can't span the extra space. These constraints, which are out of the range space of the component Formula matrix entries, are migrated to the back of the Formula matrix.
A prototypical example is an extra element column in FormulaMatrix[], which is identically zero. For example, let's say that argon is has an element column in FormulaMatrix[], but no species in the mechanism actually contains argon. Then, nc < ne. Unless the entry for desired element abundance vector for Ar is zero, then this element abundance constraint can never be satisfied. The constraint vector is not in the range space of the formula matrix.
Also, without perturbation of FormulaMatrix[], BasisOptimize[] would produce a zero pivot because the matrix would be singular (unless the argon element column was already the last column of FormulaMatrix[].
This routine borrows heavily from BasisOptimize algorithm. It finds nc constraints which span the range space of the Component Formula matrix, and assigns them as the first nc components in the formula matrix. This guarantees that BasisOptimize has a nonsingular matrix to invert.
[in]  nComponents  Number of components calculated previously. 
[in]  elementAbundances  Current value of the element abundances 
[in]  mphase  Input pointer to a MultiPhase object 
[in]  orderVectorSpecies  input vector containing the ordering of the global species in mphase. This is used to extract the component basis of the mphase object. 
[out]  orderVectorElements  Output vector containing the order of the elements that is necessary for calculation of the formula matrix. 
Definition at line 294 of file BasisOptimize.cpp.
References Cantera::BasisOptimize_print_lvl, MultiPhase::elementName(), MultiPhase::nAtoms(), MultiPhase::nElements(), MultiPhase::nSpecies(), Cantera::writelog(), and Cantera::writelogf().
Referenced by ChemEquil::estimateElementPotentials().
void equilibrate  (  const std::string &  XY, 
const std::string &  solver = "auto" , 

double  rtol = 1e9 , 

int  max_steps = 50000 , 

int  max_iter = 100 , 

int  estimate_equil = 0 , 

int  log_level = 0 

) 
Equilibrate a ThermoPhase object.
Set this phase to chemical equilibrium by calling one of several equilibrium solvers. The XY parameter indicates what two thermodynamic quantities are to be held constant during the equilibration process.
XY  String representation of what two properties are being held constant 
solver  Name of the solver to be used to equilibrate the phase. If solver = 'element_potential', the ChemEquil element potential solver will be used. If solver = 'vcs', the VCS solver will be used. If solver = 'gibbs', the MultiPhaseEquil solver will be used. If solver = 'auto', the solvers will be tried in order if the initial solver(s) fail. 
rtol  Relative tolerance 
max_steps  Maximum number of steps to take to find the solution 
max_iter  For the 'gibbs' and 'vcs' solvers, this is the maximum number of outer temperature or pressure iterations to take when T and/or P is not held fixed. 
estimate_equil  For MultiPhaseEquil solver, an integer indicating whether the solver should estimate its own initial condition. If 0, the initial mole fraction vector in the ThermoPhase object is used as the initial condition. If 1, the initial mole fraction vector is used if the element abundances are satisfied. If 1, the initial mole fraction vector is thrown out, and an estimate is formulated. 
log_level  loglevel Controls amount of diagnostic output. log_level=0 suppresses diagnostics, and increasinglyverbose messages are written as loglevel increases. 
Definition at line 1308 of file ThermoPhase.cpp.
References Cantera::debuglog(), and Phase::saveState().

inlinevirtual 
This method is used by the ChemEquil equilibrium solver.
It sets the state such that the chemical potentials satisfy
\[ \frac{\mu_k}{\hat R T} = \sum_m A_{k,m} \left(\frac{\lambda_m} {\hat R T}\right) \]
where \( \lambda_m \) is the element potential of element m. The temperature is unchanged. Any phase (ideal or not) that implements this method can be equilibrated by ChemEquil.
mu_RT  Input vector of dimensionless chemical potentials The length is equal to nSpecies(). 
Reimplemented in IdealSolnGasVPSS, IdealGasPhase, and IdealSolidSolnPhase.
Definition at line 1466 of file ThermoPhase.h.
Referenced by ChemEquil::setToEquilState().

inlinevirtual 
Indicates whether this phase type can be used with class MultiPhase for equilibrium calculations.
Returns false
for special phase types which already represent multiphase mixtures, namely PureFluidPhase.
Reimplemented in PureFluidPhase, and WaterSSTP.
Definition at line 1473 of file ThermoPhase.h.
Referenced by MultiPhase::addPhase().