DRGEP< ThermoType > Class Template Reference

The DRGEP algorithm [1] is based on. More...

Inheritance diagram for DRGEP< ThermoType >:
Collaboration diagram for DRGEP< ThermoType >:

Public Member Functions

 TypeName ("DRGEP")
 Runtime type information. More...
 DRGEP (const IOdictionary &dict, chemistryModel< ThermoType > &chemistry)
 Construct from components. More...
virtual ~DRGEP ()
 Destructor. More...
virtual void reduceMechanism (const scalar p, const scalar T, const scalarField &c, List< label > &ctos, DynamicList< label > &stoc, const label li)
 Reduce the mechanism. More...
- Public Member Functions inherited from chemistryReductionMethod< ThermoType >
 TypeName ("chemistryReductionMethod")
 Runtime type information. More...
 declareRunTimeSelectionTable (autoPtr, chemistryReductionMethod, dictionary,(const IOdictionary &dict, chemistryModel< ThermoType > &chemistry),(dict, chemistry))
 chemistryReductionMethod (chemistryModel< ThermoType > &chemistry)
 Construct from components. More...
 chemistryReductionMethod (const IOdictionary &dict, chemistryModel< ThermoType > &chemistry)
 Construct from components. More...
virtual ~chemistryReductionMethod ()
 Destructor. More...
virtual bool active () const
 Return mechanism reduction active. More...
label nSpecie ()
 Return the number of species. More...
label nActiveSpecies () const
 Return the number of active species. More...
scalar tolerance () const
 Return the tolerance. More...
const List< bool > & activeSpecies () const
 Return the active species. More...
bool reactionDisabled (const label i) const
 Return whether or not a reaction is disabled. More...
virtual void update ()
 ... More...

Additional Inherited Members

- Static Public Member Functions inherited from chemistryReductionMethod< ThermoType >
static autoPtr< chemistryReductionMethod< ThermoType > > New (const IOdictionary &dict, chemistryModel< ThermoType > &chemistry)
- Protected Member Functions inherited from chemistryReductionMethod< ThermoType >
void initReduceMechanism ()
 Protected Member Functions. More...
void endReduceMechanism (List< label > &ctos, DynamicList< label > &stoc)
 End reduction of the mechanism. More...
- Protected Attributes inherited from chemistryReductionMethod< ThermoType >
const dictionary coeffsDict_
 Dictionary that store the algorithm data. More...
chemistryModel< ThermoType > & chemistry_
 Reference to the chemistry model. More...
const label nSpecie_
 Total number of species. More...
label nActiveSpecies_
 Number of active species. More...
Field< bool > reactionsDisabled_
 List of disabled reactions (disabled = true) More...
List< bool > activeSpecies_
 List of active species (active = true) More...

Detailed Description

template<class ThermoType>
class Foam::chemistryReductionMethods::DRGEP< ThermoType >

The DRGEP algorithm [1] is based on.

|sum_i=1->Nr vAi wi dBi| rAB = ————————— , max(PA, CA)

PA = sum_i=1->Nr (max (0, vAi wi)) -> production of species A

CA = sum_i=1->Nr (max (0, -vAi wi)) -> consumption of species A

where i is the reaction index, Nr the number of reactions, vAi is the net stoichiometric coefficient of species A in the ith reaction (vAi = v''-v') , wi is the progress variable of reaction i and dBi equals 1 if reaction i involves B and O otherwise. rAB show the error introduced to the production rates of A when B and all the reactions including it are removed. It is computed as in [2] so that the algorithm is O(Nr).

DAC uses a initial set of species that represents the major parts of the combustion mechanism, i.e. H2/O2, fuel decomposition and CO2 production. Usually, it includes the fuel, HO2 and CO. Then it computes the dependence of these set to the other species. This is done by introducing R-value defined by

R_V0 (V) = max_SP(product(rij)) ,

where SP is the set of all possible paths leading from V0 to V and product(rij) is the chain product of the weights of the edges along the given path. The R-value for the initial set species is 1.

When the R-value of a species is larger than a user-defined tolerance then the species is included in the simplified mechanism. Otherwise, the species is removed along with all the reactions including it.

During this process, instead of looking over all species like described in [1], the algorithm implemented here creates dynamic list to retain the initialised edges only (see [2]).

To avoid using the target species when they are not contributing yet or anymore to the system, a coefficient based on the exchange of element is introduced:

NTa |PT - CT| alphaTa = —————- Pa

Pa = sum_speciesS NSa max(0, PS-CS)

where 'a' refers to different elements present in the system (namely C, H, O and N for conventional hydrocarbon combustion), NTa is the number of element a in species T. When this coefficient alpha is below the specified threshold, the species is removed from the search initiating set. In the original paper from Pepiot-Desjardins et al.[2], this coefficient is further transformed to compute a global normalised scaling coefficient but here as it is dynamically computed, alpha is not introduced in the calculation of R.


    [1] Pepiot-Desjardins, P., & Pitsch, H. (2008).
    An efficient error-propagation-based reduction method for large
    chemical kinetic mechanisms.
    Combustion and Flame, 154(1), 67-81.

    [2] Lu, T., & Law, C. K. (2006).
    Linear time reduction of large kinetic mechanisms with directed
    relation graph: n-Heptane and iso-octane.
    Combustion and Flame, 144(1), 24-36.
Source files

Definition at line 119 of file DRGEP.H.

Constructor & Destructor Documentation


◆ ~DRGEP()



Definition at line 97 of file DRGEP.C.

Member Function Documentation

◆ TypeName()

TypeName ( "DRGEP< ThermoType >"  )

Runtime type information.

◆ reduceMechanism()

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