The 1- or 2-parameter Tsang falloff parameterization. More...

#include <Falloff.h>

Inheritance diagram for TsangRate:

Detailed Description

The 1- or 2-parameter Tsang falloff parameterization.

The Tsang falloff model is adapted from that of Troe. It provides a constant or linear in temperature value for \( F_{cent} \):

\[ F_{cent} = A + B*T \]

The value of \( F_{cent} \) is then applied to Troe's model for the determination of the value of \( F(T, P_r) \):

\[ \log_{10} F(T, P_r) = \frac{\log_{10} F_{cent}(T)}{1 + f_1^2} \]

where

\[ f_1 = \frac{\log_{10} P_r + C}{N - 0.14 (\log_{10} P_r + C)} \]

\[ C = -0.4 - 0.67 \log_{10} F_{cent} \]

\[ N = 0.75 - 1.27 \log_{10} F_{cent} \]

References:

Example of reaction database developed by Tsang utilizing this format [44]
Example of Chemkin implementation of Tsang format (supplemental materials) [22]

Definition at line 491 of file Falloff.h.

Public Member Functions
	TsangRate ()
	Constructor.

	TsangRate (const AnyMap &node, const UnitStack &rate_units={})

	TsangRate (const ArrheniusRate &low, const ArrheniusRate &high, const vector< double > &c)

unique_ptr< MultiRateBase >	newMultiRate () const override
	Create a rate evaluator for reactions of a particular derived type.

void	setFalloffCoeffs (const vector< double > &c) override
	Set coefficients used by parameterization.

void	getFalloffCoeffs (vector< double > &c) const override
	Retrieve coefficients of the falloff parameterization.

void	updateTemp (double T, double *work) const override
	Update the temperature parameters in the representation.

double	F (double pr, const double *work) const override
	The falloff function.

const string	subType () const override
	String identifying sub-type of reaction rate specialization.

size_t	nParameters () const override
	Returns the number of parameters used by this parameterization.

void	setParameters (const AnyMap &node, const UnitStack &rate_units) override
	Set parameters.

void	getParameters (AnyMap &node) const override
	Get parameters.

Public Member Functions inherited from FalloffRate
	FalloffRate (const AnyMap &node, const UnitStack &rate_units={})

virtual void	setFalloffCoeffs (const vector< double > &c)
	Set coefficients of the falloff parameterization.

virtual void	getFalloffCoeffs (vector< double > &c) const
	Retrieve coefficients of the falloff parameterization.

virtual void	updateTemp (double T, double *work) const
	Update the temperature-dependent portions of the falloff function, if any, and store them in the 'work' array.

virtual double	F (double pr, const double *work) const
	The falloff function.

double	evalF (double T, double conc3b)
	Evaluate falloff function at current conditions.

const string	type () const override
	String identifying reaction rate specialization.

virtual size_t	nParameters () const
	Returns the number of parameters used by this parameterization.

void	setParameters (const AnyMap &node, const UnitStack &rate_units) override
	Set parameters.

void	getParameters (AnyMap &node) const override
	Get parameters.

double	evalFromStruct (const FalloffData &shared_data)
	Evaluate reaction rate.

void	check (const string &equation) override
	Check basic syntax and settings of reaction rate expression.

void	validate (const string &equation, const Kinetics &kin) override
	Validate the reaction rate expression.

bool	allowNegativePreExponentialFactor () const
	Get flag indicating whether negative A values are permitted.

void	setAllowNegativePreExponentialFactor (bool value)
	Set flag indicating whether negative A values are permitted.

bool	chemicallyActivated () const
	Get flag indicating whether reaction is chemically activated.

void	setChemicallyActivated (bool activated)
	Set flag indicating whether reaction is chemically activated.

ArrheniusRate &	lowRate ()
	Get reaction rate in the low-pressure limit.

void	setLowRate (const ArrheniusRate &low)
	Set reaction rate in the low-pressure limit.

ArrheniusRate &	highRate ()
	Get reaction rate in the high-pressure limit.

void	setHighRate (const ArrheniusRate &high)
	Set reaction rate in the high-pressure limit.

Public Member Functions inherited from ReactionRate
	ReactionRate (const ReactionRate &other)

ReactionRate &	operator= (const ReactionRate &other)

virtual unique_ptr< MultiRateBase >	newMultiRate () const
	Create a rate evaluator for reactions of a particular derived type.

virtual const string	type () const =0
	String identifying reaction rate specialization.

virtual const string	subType () const
	String identifying sub-type of reaction rate specialization.

virtual void	setParameters (const AnyMap &node, const UnitStack &units)
	Set parameters.

AnyMap	parameters () const
	Return the parameters such that an identical Reaction could be reconstructed using the newReaction() function.

const Units &	conversionUnits () const
	Get the units for converting the leading term in the reaction rate expression.

virtual void	setRateUnits (const UnitStack &rate_units)
	Set the units of the reaction rate expression.

virtual void	check (const string &equation)
	Check basic syntax and settings of reaction rate expression.

virtual void	validate (const string &equation, const Kinetics &kin)
	Validate the reaction rate expression.

size_t	rateIndex () const
	Reaction rate index within kinetics evaluator.

void	setRateIndex (size_t idx)
	Set reaction rate index within kinetics evaluator.

virtual void	setContext (const Reaction &rxn, const Kinetics &kin)
	Set context of reaction rate evaluation.

double	eval (double T)
	Evaluate reaction rate based on temperature.

double	eval (double T, double extra)
	Evaluate reaction rate based on temperature and an extra parameter.

double	eval (double T, const vector< double > &extra)
	Evaluate reaction rate based on temperature and an extra vector parameter.

bool	valid () const
	Get flag indicating whether reaction rate is set up correctly.

bool	compositionDependent ()
	Boolean indicating whether rate has compositional dependence.

void	setCompositionDependence (bool comp_dep)
	Set rate compositional dependence.

Protected Attributes
double	m_a
	parameter a in the Tsang F_cent formulation. Dimensionless

double	m_b
	parameter b in the Tsang F_cent formulation. [K^-1]

Protected Attributes inherited from FalloffRate
ArrheniusRate	m_lowRate
	The reaction rate in the low-pressure limit.

ArrheniusRate	m_highRate
	The reaction rate in the high-pressure limit.

bool	m_chemicallyActivated = false
	Flag labeling reaction as chemically activated.

bool	m_negativeA_ok = false
	Flag indicating whether negative A values are permitted.

double	m_rc_low = NAN
	Evaluated reaction rate in the low-pressure limit.

double	m_rc_high = NAN
	Evaluated reaction rate in the high-pressure limit.

vector< double >	m_work
	Work vector.

Protected Attributes inherited from ReactionRate
AnyMap	m_input
	Input data used for specific models.

size_t	m_rate_index = npos
	Index of reaction rate within kinetics evaluator.

bool	m_valid = false
	Flag indicating whether reaction rate is set up correctly.

bool	m_composition_dependent_rate = false
	Flag indicating composition dependent rate.

Units	m_conversion_units {0.}
	Units of the leading term in the reaction rate expression.

Additional Inherited Members
virtual void	getParameters (AnyMap &node) const
	Get parameters.

Constructor & Destructor Documentation

◆ TsangRate() [1/3]

TsangRate ( )

inline

Constructor.

Definition at line 495 of file Falloff.h.

◆ TsangRate() [2/3]

TsangRate	(	const AnyMap &	node,
		const UnitStack &	rate_units = `{}`
	)

Definition at line 450 of file Falloff.cpp.

◆ TsangRate() [3/3]

TsangRate	(	const ArrheniusRate &	low,
		const ArrheniusRate &	high,
		const vector< double > &	c
	)

inline

Definition at line 501 of file Falloff.h.

Member Function Documentation

◆ newMultiRate()

unique_ptr< MultiRateBase > newMultiRate ( ) const

inlineoverridevirtual

Create a rate evaluator for reactions of a particular derived type.

Derived classes usually implement this as:

unique_ptr<MultiRateBase> newMultiRate() const override {

return make_unique<MultiRate<RateType, DataType>>();

Cantera::TsangRate::newMultiRate

unique_ptr< MultiRateBase > newMultiRate() const override

Create a rate evaluator for reactions of a particular derived type.

Definition Falloff.h:509

where RateType is the derived class name and DataType is the corresponding container for parameters needed to evaluate reactions of that type.

Reimplemented from ReactionRate.

Definition at line 509 of file Falloff.h.

◆ setFalloffCoeffs()

void setFalloffCoeffs ( const vector< double > & c )

overridevirtual

Set coefficients used by parameterization.

Parameters

c	Vector of one or two doubles: The doubles are the parameters, a and (optionally) b of the Tsang F_cent parameterization

Reimplemented from FalloffRate.

Definition at line 456 of file Falloff.cpp.

◆ getFalloffCoeffs()

void getFalloffCoeffs ( vector< double > & c ) const

overridevirtual

Retrieve coefficients of the falloff parameterization.

Parameters

c	Vector of coefficients of the parameterization. The number and meaning of these coefficients is subclass-dependent.

Reimplemented from FalloffRate.

Definition at line 474 of file Falloff.cpp.

◆ updateTemp()

void updateTemp	(	double	T,
		double *	work
	)		const

overridevirtual

Update the temperature parameters in the representation.

Parameters

T	Temperature (Kelvin)
work	Vector of working space, length 1, representing the temperature-dependent part of the parameterization.

Reimplemented from FalloffRate.

Definition at line 485 of file Falloff.cpp.

◆ F()

double F	(	double	pr,
		const double *	work
	)		const

overridevirtual

The falloff function.

Parameters

pr	reduced pressure (dimensionless).
work	array of size workSize() containing cached temperature-dependent intermediate results from a prior call to updateTemp.

Returns: the value of the falloff function \( F \) defined above

Reimplemented from FalloffRate.

Definition at line 491 of file Falloff.cpp.

◆ subType()

const string subType ( ) const

inlineoverridevirtual

String identifying sub-type of reaction rate specialization.

Reimplemented from ReactionRate.

Definition at line 532 of file Falloff.h.

◆ nParameters()

size_t nParameters ( ) const

inlineoverridevirtual

Returns the number of parameters used by this parameterization.

The values of these parameters can be obtained from getParameters().

Reimplemented from FalloffRate.

Definition at line 536 of file Falloff.h.

◆ setParameters()

void setParameters	(	const AnyMap &	node,
		const UnitStack &	units
	)

overridevirtual

Set parameters.

Parameters

node	AnyMap object containing reaction rate specification
units	unit definitions specific to rate information

Reimplemented from FalloffRate.

Definition at line 501 of file Falloff.cpp.

◆ getParameters()

void getParameters ( AnyMap & node ) const

overridevirtual

Get parameters.

Parameters

node	AnyMap containing rate information Store the parameters of a ReactionRate needed to reconstruct an identical object. Does not include user-defined fields available in the m_input map.

Reimplemented from FalloffRate.

Definition at line 519 of file Falloff.cpp.

Member Data Documentation

◆ m_a

double m_a

protected

parameter a in the Tsang F_cent formulation. Dimensionless

Definition at line 546 of file Falloff.h.

◆ m_b

double m_b

protected

parameter b in the Tsang F_cent formulation. [K^-1]

Definition at line 549 of file Falloff.h.

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

Detailed Description

Public Member Functions

Protected Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ TsangRate() [1/3]

◆ TsangRate() [2/3]

◆ TsangRate() [3/3]

Member Function Documentation

◆ newMultiRate()

◆ setFalloffCoeffs()

◆ getFalloffCoeffs()

◆ updateTemp()

◆ F()

◆ subType()

◆ nParameters()

◆ setParameters()

◆ getParameters()

Member Data Documentation

◆ m_a

◆ m_b