Blowers Masel reaction rate type depends on the enthalpy of reaction. More...

#include <BlowersMaselRate.h>

Inheritance diagram for BlowersMaselRate:

Detailed Description

Blowers Masel reaction rate type depends on the enthalpy of reaction.

The Blowers Masel approximation [3] adjusts the activation energy based on enthalpy change of a reaction:

\begin{eqnarray*} E_a &=& 0\; &\text{if }\Delta H < -4E_0 \\ E_a &=& \Delta H\; &\text{if }\Delta H > 4E_0 \\ E_a &=& \frac{(w + \Delta H / 2)(V_P - 2w + \Delta H)^2}{(V_P^2 - 4w^2 + (\Delta H)^2)}\; &\text{otherwise} \end{eqnarray*}

where

\[ V_P = \frac{2w (w + E_0)}{w - E_0}, \]

\( w \) is the average bond dissociation energy of the bond breaking and that being formed in the reaction. Since the expression is very insensitive to \( w \) for \( w >= 2 E_0 \), \( w \) can be approximated to an arbitrary high value like 1000 kJ/mol.

After the activation energy is determined by Blowers-Masel approximation, it can be plugged into Arrhenius function to calculate the rate constant.

\[ k_f = A T^b \exp (-E_a/RT) \]

Definition at line 69 of file BlowersMaselRate.h.

Public Member Functions
	BlowersMaselRate ()
	Default constructor.

	BlowersMaselRate (double A, double b, double Ea0, double w)
	Constructor.

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

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

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

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

double	evalRate (double logT, double recipT) const
	Evaluate reaction rate.

void	updateFromStruct (const BlowersMaselData &shared_data)
	Update information specific to reaction.

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

double	ddTScaledFromStruct (const BlowersMaselData &shared_data) const
	Evaluate derivative of reaction rate with respect to temperature divided by reaction rate.

double	activationEnergy () const override
	Return the activation energy Ea [J/kmol] The value corresponds to the constant specified by input parameters;.

double	bondEnergy () const
	Return the bond dissociation energy w [J/kmol].

double	deltaH () const
	Return current enthalpy change of reaction [J/kmol].

void	setDeltaH (double deltaH)
	Set current enthalpy change of reaction [J/kmol].

Public Member Functions inherited from ArrheniusBase
	ArrheniusBase ()
	Default constructor.

	ArrheniusBase (double A, double b, double Ea)
	Constructor.

	ArrheniusBase (const AnyValue &rate, const UnitSystem &units, const UnitStack &rate_units)
	Constructor based on AnyValue content.

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

void	setRateParameters (const AnyValue &rate, const UnitSystem &units, const UnitStack &rate_units)
	Perform object setup based on AnyValue node information.

void	getRateParameters (AnyMap &node) const
	Get Arrhenius parameters used to populate the `rate-coefficient` or equivalent field.

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

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

void	check (const string &equation) override
	Check rate expression.

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

virtual double	preExponentialFactor () const
	Return the pre-exponential factor A (in m, kmol, s to powers depending on the reaction order)

virtual double	temperatureExponent () const
	Return the temperature exponent b

virtual double	activationEnergy () const
	Return the activation energy Ea [J/kmol] The value corresponds to the constant specified by input parameters;.

double	order () const
	Return reaction order associated with the reaction rate.

void	setRateUnits (const UnitStack &rate_units) override
	Set units of 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.

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 Member Functions
double	effectiveActivationEnergy_R (double deltaH_R) const
	Return the effective activation energy (a function of the delta H of reaction) divided by the gas constant (that is, the activation temperature) [K].

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

Protected Attributes
vector< pair< size_t, double > >	m_stoich_coeffs
	Pairs of species indices and multipliers to calculate enthalpy change.

double	m_deltaH_R = 0.0
	enthalpy change of reaction (in temperature units)

Protected Attributes inherited from ArrheniusBase
bool	m_negativeA_ok = false
	Permissible negative A values.

double	m_A = NAN
	Pre-exponential factor.

double	m_b = NAN
	Temperature exponent.

double	m_Ea_R = 0.
	Activation energy (in temperature units)

double	m_E4_R = 0.
	Optional 4th energy parameter (in temperature units)

double	m_logA = NAN
	Logarithm of pre-exponential factor.

double	m_order = NAN
	Reaction order.

string	m_A_str = "A"
	The string for the pre-exponential factor.

string	m_b_str = "b"
	The string for temperature exponent.

string	m_Ea_str = "Ea"
	The string for activation energy.

string	m_E4_str = ""
	The string for an optional 4th parameter.

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.

Constructor & Destructor Documentation

◆ BlowersMaselRate() [1/3]

BlowersMaselRate ( )

Default constructor.

Definition at line 39 of file BlowersMaselRate.cpp.

◆ BlowersMaselRate() [2/3]

BlowersMaselRate	(	double	A,
		double	b,
		double	Ea0,
		double	w
	)

Constructor.

Parameters

A	Pre-exponential factor. The unit system is (kmol, m, s); actual units depend on the reaction order and the dimensionality (surface or bulk).
b	Temperature exponent (non-dimensional)
Ea0	Intrinsic activation energy in energy units [J/kmol]
w	Average bond dissociation energy of the bond being formed and broken in the reaction, in energy units [J/kmol]

Definition at line 45 of file BlowersMaselRate.cpp.

◆ BlowersMaselRate() [3/3]

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

explicit

Definition at line 53 of file BlowersMaselRate.cpp.

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::BlowersMaselRate::newMultiRate

unique_ptr< MultiRateBase > newMultiRate() const override

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

Definition BlowersMaselRate.h:89

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 89 of file BlowersMaselRate.h.

◆ type()

const string type ( ) const

inlineoverridevirtual

String identifying reaction rate specialization.

Implements ReactionRate.

Definition at line 93 of file BlowersMaselRate.h.

◆ setContext()

void setContext	(	const Reaction &	rxn,
		const Kinetics &	kin
	)

overridevirtual

Set context of reaction rate evaluation.

Parameters

rxn	Reaction object associated with rate
kin	Kinetics object used for rate evaluation This method allows for passing of information specific to the associated reaction when a ReactionRate object is added a MultiRate reaction evaluator.

Reimplemented from ReactionRate.

Definition at line 67 of file BlowersMaselRate.cpp.

◆ evalRate()

double evalRate	(	double	logT,
		double	recipT
	)		const

inline

Evaluate reaction rate.

Definition at line 100 of file BlowersMaselRate.h.

◆ updateFromStruct()

void updateFromStruct ( const BlowersMaselData & shared_data )

inline

Update information specific to reaction.

Definition at line 106 of file BlowersMaselRate.h.

◆ evalFromStruct()

double evalFromStruct ( const BlowersMaselData & shared_data ) const

inline

Evaluate reaction rate.

Parameters

shared_data data shared by all reactions of a given type

Definition at line 120 of file BlowersMaselRate.h.

◆ ddTScaledFromStruct()

double ddTScaledFromStruct ( const BlowersMaselData & shared_data ) const

Evaluate derivative of reaction rate with respect to temperature divided by reaction rate.

This method does not consider potential changes due to a changed reaction enthalpy. A corresponding warning is raised.

Parameters

shared_data data shared by all reactions of a given type

Definition at line 59 of file BlowersMaselRate.cpp.

◆ effectiveActivationEnergy_R()

double effectiveActivationEnergy_R ( double deltaH_R ) const

inlineprotected

Return the effective activation energy (a function of the delta H of reaction) divided by the gas constant (that is, the activation temperature) [K].

Definition at line 137 of file BlowersMaselRate.h.

◆ activationEnergy()

double activationEnergy ( ) const

inlineoverridevirtual

Return the activation energy Ea [J/kmol] The value corresponds to the constant specified by input parameters;.

Class specializations may provide alternate definitions that describe an effective activation energy that depends on the thermodynamic state.

Reimplemented from ArrheniusBase.

Definition at line 152 of file BlowersMaselRate.h.

◆ bondEnergy()

double bondEnergy ( ) const

inline

Return the bond dissociation energy w [J/kmol].

Definition at line 157 of file BlowersMaselRate.h.

◆ deltaH()

double deltaH ( ) const

inline

Return current enthalpy change of reaction [J/kmol].

Definition at line 162 of file BlowersMaselRate.h.

◆ setDeltaH()

void setDeltaH ( double deltaH )

inline

Set current enthalpy change of reaction [J/kmol].

Note: used for testing purposes only; this quantity is not an independent variable and will be overwritten during an update of the state.

Warning: This method is an experimental part of the Cantera API and may be changed or removed without notice.

Definition at line 174 of file BlowersMaselRate.h.

Member Data Documentation

◆ m_stoich_coeffs

vector<pair<size_t, double> > m_stoich_coeffs

protected

Pairs of species indices and multipliers to calculate enthalpy change.

Definition at line 180 of file BlowersMaselRate.h.

◆ m_deltaH_R

double m_deltaH_R = 0.0

protected

enthalpy change of reaction (in temperature units)

Definition at line 182 of file BlowersMaselRate.h.

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

Detailed Description

Public Member Functions

Protected Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆ BlowersMaselRate() [1/3]

◆ BlowersMaselRate() [2/3]

◆ BlowersMaselRate() [3/3]

Member Function Documentation

◆ newMultiRate()

◆ type()

◆ setContext()

◆ evalRate()

◆ updateFromStruct()

◆ evalFromStruct()

◆ ddTScaledFromStruct()

◆ effectiveActivationEnergy_R()

◆ activationEnergy()

◆ bondEnergy()

◆ deltaH()

◆ setDeltaH()

Member Data Documentation

◆ m_stoich_coeffs

◆ m_deltaH_R