MixTransport Class Reference

Class MixTransport implements mixture-averaged transport properties for ideal gas mixtures. More...

#include <MixTransport.h>

Inheritance diagram for MixTransport:

Detailed Description

Class MixTransport implements mixture-averaged transport properties for ideal gas mixtures.

The model is based on that described in Kee, et al. [17].

The viscosity is computed using the Wilke mixture rule (kg /m /s)

\[ \mu = \sum_k \frac{\mu_k X_k}{\sum_j \Phi_{k,j} X_j}. \]

Here \( \mu_k \) is the viscosity of pure species k, and

\[ \Phi_{k,j} = \frac{\left[1 + \sqrt{\left(\frac{\mu_k}{\mu_j}\sqrt{\frac{M_j}{M_k}}\right)}\right]^2} {\sqrt{8}\sqrt{1 + M_k/M_j}} \]

The thermal conductivity is computed from the following mixture rule:

\[ \lambda = 0.5 \left( \sum_k X_k \lambda_k + \frac{1}{\sum_k X_k/\lambda_k} \right) \]

It's used to compute the flux of energy due to a thermal gradient

\[ j_T = - \lambda \nabla T \]

The flux of energy has units of energy (kg m2 /s2) per second per area.

The units of lambda are W / m K which is equivalent to kg m / s^3 K.

Definition at line 54 of file MixTransport.h.

Public Member Functions
	MixTransport ()=default
	Default constructor.
string	transportModel () const override
	Identifies the model represented by this Transport object.
void	getThermalDiffCoeffs (double *const dt) override
	Return the thermal diffusion coefficients.
double	thermalConductivity () override
	Returns the mixture thermal conductivity (W/m /K)
void	getMobilities (double *const mobil) override
	Get the Electrical mobilities (m^2/V/s).
void	update_T () override
	Update the internal parameters whenever the temperature has changed.
void	update_C () override
	Update the internal parameters whenever the concentrations have changed.
void	getSpeciesFluxes (size_t ndim, const double *const grad_T, size_t ldx, const double *const grad_X, size_t ldf, double *const fluxes) override
	Get the species diffusive mass fluxes wrt to the mass averaged velocity, given the gradients in mole fraction and temperature.
void	init (ThermoPhase *thermo, int mode=0, int log_level=0) override
	Initialize a transport manager.
Public Member Functions inherited from GasTransport
double	viscosity () override
	Viscosity of the mixture (kg /m /s)
void	getSpeciesViscosities (double *const visc) override
	Get the pure-species viscosities.
void	getBinaryDiffCoeffs (const size_t ld, double *const d) override
	Returns the matrix of binary diffusion coefficients.
void	getMixDiffCoeffs (double *const d) override
	Returns the Mixture-averaged diffusion coefficients [m^2/s].
void	getMixDiffCoeffsMole (double *const d) override
	Returns the mixture-averaged diffusion coefficients [m^2/s].
void	getMixDiffCoeffsMass (double *const d) override
	Returns the mixture-averaged diffusion coefficients [m^2/s].
void	getViscosityPolynomial (size_t i, double *coeffs) const override
	Return the polynomial fits to the viscosity of species i.
void	getConductivityPolynomial (size_t i, double *coeffs) const override
	Return the temperature fits of the heat conductivity of species i.
void	getBinDiffusivityPolynomial (size_t i, size_t j, double *coeffs) const override
	Return the polynomial fits to the binary diffusivity of species pair (i, j)
void	getCollisionIntegralPolynomial (size_t i, size_t j, double *astar_coeffs, double *bstar_coeffs, double *cstar_coeffs) const override
	Return the polynomial fits to the collision integral of species pair (i, j)
void	setViscosityPolynomial (size_t i, double *coeffs) override
	Modify the polynomial fits to the viscosity of species i.
void	setConductivityPolynomial (size_t i, double *coeffs) override
	Modify the temperature fits of the heat conductivity of species i.
void	setBinDiffusivityPolynomial (size_t i, size_t j, double *coeffs) override
	Modify the polynomial fits to the binary diffusivity of species pair (i, j)
void	setCollisionIntegralPolynomial (size_t i, size_t j, double *astar_coeffs, double *bstar_coeffs, double *cstar_coeffs, bool actualT) override
	Modify the polynomial fits to the collision integral of species pair (i, j)
void	init (ThermoPhase *thermo, int mode=0, int log_level=0) override
	Initialize a transport manager.
bool	CKMode () const override
	Boolean indicating the form of the transport properties polynomial fits.
Public Member Functions inherited from Transport
	Transport ()=default
	Constructor.
	Transport (const Transport &)=delete
Transport &	operator= (const Transport &)=delete
virtual string	transportModel () const
	Identifies the model represented by this Transport object.
ThermoPhase &	thermo ()
	Phase object.
void	checkSpeciesIndex (size_t k) const
	Check that the specified species index is in range.
void	checkSpeciesArraySize (size_t kk) const
	Check that an array size is at least nSpecies().
virtual void	getSpeciesFluxes (size_t ndim, const double *const grad_T, size_t ldx, const double *const grad_X, size_t ldf, double *const fluxes)
	Get the species diffusive mass fluxes wrt to the specified solution averaged velocity, given the gradients in mole fraction and temperature.
virtual void	getMolarFluxes (const double *const state1, const double *const state2, const double delta, double *const cfluxes)
	Get the molar fluxes [kmol/m^2/s], given the thermodynamic state at two nearby points.
virtual void	getMassFluxes (const double *state1, const double *state2, double delta, double *mfluxes)
	Get the mass fluxes [kg/m^2/s], given the thermodynamic state at two nearby points.
virtual void	getThermalDiffCoeffs (double *const dt)
	Return a vector of Thermal diffusion coefficients [kg/m/sec].
virtual void	getBinaryDiffCoeffs (const size_t ld, double *const d)
	Returns the matrix of binary diffusion coefficients [m^2/s].
virtual void	getMultiDiffCoeffs (const size_t ld, double *const d)
	Return the Multicomponent diffusion coefficients. Units: [m^2/s].
virtual void	getMixDiffCoeffs (double *const d)
	Returns a vector of mixture averaged diffusion coefficients.
virtual void	getMixDiffCoeffsMole (double *const d)
	Returns a vector of mixture averaged diffusion coefficients.
virtual void	getMixDiffCoeffsMass (double *const d)
	Returns a vector of mixture averaged diffusion coefficients.
virtual void	getViscosityPolynomial (size_t i, double *coeffs) const
	Return the polynomial fits to the viscosity of species i.
virtual void	getConductivityPolynomial (size_t i, double *coeffs) const
	Return the temperature fits of the heat conductivity of species i.
virtual void	getBinDiffusivityPolynomial (size_t i, size_t j, double *coeffs) const
	Return the polynomial fits to the binary diffusivity of species pair (i, j)
virtual void	getCollisionIntegralPolynomial (size_t i, size_t j, double *astar_coeffs, double *bstar_coeffs, double *cstar_coeffs) const
	Return the polynomial fits to the collision integral of species pair (i, j)
virtual void	setViscosityPolynomial (size_t i, double *coeffs)
	Modify the polynomial fits to the viscosity of species i.
virtual void	setConductivityPolynomial (size_t i, double *coeffs)
	Modify the temperature fits of the heat conductivity of species i.
virtual void	setBinDiffusivityPolynomial (size_t i, size_t j, double *coeffs)
	Modify the polynomial fits to the binary diffusivity of species pair (i, j)
virtual void	setCollisionIntegralPolynomial (size_t i, size_t j, double *astar_coeffs, double *bstar_coeffs, double *cstar_coeffs, bool flag)
	Modify the polynomial fits to the collision integral of species pair (i, j)
AnyMap	parameters () const
	Return the parameters for a phase definition which are needed to reconstruct an identical object using the newTransport function.
virtual double	bulkViscosity ()
	The bulk viscosity in Pa-s.
virtual double	electricalConductivity ()
	The electrical conductivity (Siemens/m).

Protected Member Functions
void	updateCond_T ()
	Update the temperature dependent parts of the species thermal conductivities.
Protected Member Functions inherited from GasTransport
virtual void	update_T ()
virtual void	update_C ()=0
virtual void	updateViscosity_T ()
	Update the temperature-dependent viscosity terms.
virtual void	updateSpeciesViscosities ()
	Update the pure-species viscosities.
virtual void	updateDiff_T ()
	Update the binary diffusion coefficients.
virtual void	setupCollisionParameters ()
	Setup parameters for a new kinetic-theory-based transport manager for low-density gases.
void	setupCollisionIntegral ()
	Setup range for polynomial fits to collision integrals of Monchick & Mason [29].
void	getTransportData ()
	Read the transport database.
void	makePolarCorrections (size_t i, size_t j, double &f_eps, double &f_sigma)
	Corrections for polar-nonpolar binary diffusion coefficients.
void	fitCollisionIntegrals (MMCollisionInt &integrals)
	Generate polynomial fits to collision integrals.
virtual void	fitProperties (MMCollisionInt &integrals)
	Generate polynomial fits to the viscosity \( \eta \) and conductivity \( \lambda \).
virtual void	fitDiffCoeffs (MMCollisionInt &integrals)
	Generate polynomial fits to the binary diffusion coefficients.
void	getBinDiffCorrection (double t, MMCollisionInt &integrals, size_t k, size_t j, double xk, double xj, double &fkj, double &fjk)
	Second-order correction to the binary diffusion coefficients.

Protected Attributes
vector< double >	m_cond
	vector of species thermal conductivities (W/m /K)
double	m_lambda = 0.0
	Internal storage for the calculated mixture thermal conductivity.
bool	m_spcond_ok = false
	Update boolean for the species thermal conductivities.
bool	m_condmix_ok = false
	Update boolean for the mixture rule for the mixture thermal conductivity.
Protected Attributes inherited from GasTransport
vector< double >	m_molefracs
	Vector of species mole fractions.
double	m_viscmix = 0.0
	Internal storage for the viscosity of the mixture (kg /m /s)
bool	m_visc_ok = false
	Update boolean for mixture rule for the mixture viscosity.
bool	m_viscwt_ok = false
	Update boolean for the weighting factors for the mixture viscosity.
bool	m_spvisc_ok = false
	Update boolean for the species viscosities.
bool	m_bindiff_ok = false
	Update boolean for the binary diffusivities at unit pressure.
int	m_mode = 0
	Type of the polynomial fits to temperature.
DenseMatrix	m_phi
	m_phi is a Viscosity Weighting Function. size = m_nsp * n_nsp
vector< double >	m_spwork
	work space length = m_kk
vector< double >	m_visc
	vector of species viscosities (kg /m /s).
vector< vector< double > >	m_visccoeffs
	Polynomial fits to the viscosity of each species.
vector< double >	m_mw
	Local copy of the species molecular weights.
DenseMatrix	m_wratjk
	Holds square roots of molecular weight ratios.
DenseMatrix	m_wratkj1
	Holds square roots of molecular weight ratios.
vector< double >	m_sqvisc
	vector of square root of species viscosities sqrt(kg /m /s).
vector< double >	m_polytempvec
	Powers of the ln temperature, up to fourth order.
double	m_temp = -1.0
	Current value of the temperature at which the properties in this object are calculated (Kelvin).
double	m_kbt = 0.0
	Current value of Boltzmann constant times the temperature (Joules)
double	m_sqrt_t = 0.0
	current value of temperature to 1/2 power
double	m_logt = 0.0
	Current value of the log of the temperature.
double	m_t14 = 0.0
	Current value of temperature to 1/4 power.
vector< vector< double > >	m_diffcoeffs
	Polynomial fits to the binary diffusivity of each species.
DenseMatrix	m_bdiff
	Matrix of binary diffusion coefficients at the reference pressure and the current temperature Size is nsp x nsp.
vector< vector< double > >	m_condcoeffs
	temperature fits of the heat conduction
vector< vector< int > >	m_poly
	Indices for the (i,j) interaction in collision integral fits.
vector< vector< double > >	m_omega22_poly
	Fit for omega22 collision integral.
vector< vector< int > >	m_star_poly_uses_actualT
	Flag to indicate for which (i,j) interaction pairs the actual temperature is used instead of the reduced temperature.
vector< vector< double > >	m_astar_poly
	Fit for astar collision integral.
vector< vector< double > >	m_bstar_poly
	Fit for bstar collision integral.
vector< vector< double > >	m_cstar_poly
	Fit for cstar collision integral.
vector< double >	m_zrot
	Rotational relaxation number for each species.
vector< double >	m_crot
	Dimensionless rotational heat capacity of each species.
vector< bool >	m_polar
	Vector of booleans indicating whether a species is a polar molecule.
vector< double >	m_alpha
	Polarizability of each species in the phase.
vector< double >	m_eps
	Lennard-Jones well-depth of the species in the current phase.
vector< double >	m_sigma
	Lennard-Jones diameter of the species in the current phase.
DenseMatrix	m_reducedMass
	This is the reduced mass of the interaction between species i and j.
DenseMatrix	m_diam
	hard-sphere diameter for (i,j) collision
DenseMatrix	m_epsilon
	The effective well depth for (i,j) collisions.
DenseMatrix	m_dipole
	The effective dipole moment for (i,j) collisions.
DenseMatrix	m_delta
	Reduced dipole moment of the interaction between two species.
vector< double >	m_w_ac
	Pitzer acentric factor.
vector< double >	m_disp
	Dispersion coefficient.
vector< double >	m_quad_polar
	Quadrupole polarizability.
int	m_log_level = 0
	Level of verbose printing during initialization.
Protected Attributes inherited from Transport
ThermoPhase *	m_thermo
	pointer to the object representing the phase
size_t	m_nsp = 0
	Number of species.

Constructor & Destructor Documentation

MixTransport()

MixTransport ( )

default

Default constructor.

Member Function Documentation

transportModel()

string transportModel ( ) const

inlineoverridevirtual

Identifies the model represented by this Transport object.

Each derived class should override this method to return a meaningful identifier.

Since

New in Cantera 3.0. The name returned by this method corresponds to the canonical name used in the YAML input format.

Reimplemented from Transport.

Reimplemented in UnityLewisTransport.

Definition at line 60 of file MixTransport.h.

getThermalDiffCoeffs()

void getThermalDiffCoeffs ( double *const  dt )

overridevirtual

Return the thermal diffusion coefficients.

For this approximation, these are all zero.

Parameters

dt	Vector of thermal diffusion coefficients. Units = kg/m/s

Reimplemented from Transport.

Definition at line 51 of file MixTransport.cpp.

thermalConductivity()

double thermalConductivity ( )

overridevirtual

Returns the mixture thermal conductivity (W/m /K)

The thermal conductivity is computed from the following mixture rule:

\[ \lambda = 0.5 \left( \sum_k X_k \lambda_k + \frac{1}{\sum_k X_k/\lambda_k} \right) \]

It's used to compute the flux of energy due to a thermal gradient

\[ j_T = - \lambda \nabla T \]

The flux of energy has units of energy (kg m2 /s2) per second per area.

The units of lambda are W / m K which is equivalent to kg m / s^3 K.

Returns

the mixture thermal conductivity, with units of W/m/K

Reimplemented from Transport.

Definition at line 32 of file MixTransport.cpp.

getMobilities()

void getMobilities ( double *const  mobil )

overridevirtual

Get the Electrical mobilities (m^2/V/s).

This function returns the mobilities. In some formulations this is equal to the normal mobility multiplied by Faraday's constant.

Here, the mobility is calculated from the diffusion coefficient using the Einstein relation

\[ \mu^e_k = \frac{F D_k}{R T} \]

Parameters

mobil

Returns the mobilities of the species in array mobil. The array must be dimensioned at least as large as the number of species.

Reimplemented from Transport.

Definition at line 23 of file MixTransport.cpp.

update_T()

void update_T ( )

overridevirtual

Update the internal parameters whenever the temperature has changed.

This is called whenever a transport property is requested if the temperature has changed since the last call to update_T().

Reimplemented from GasTransport.

Definition at line 83 of file MixTransport.cpp.

update_C()

void update_C ( )

overridevirtual

Update the internal parameters whenever the concentrations have changed.

This is called whenever a transport property is requested if the concentrations have changed since the last call to update_C().

Implements GasTransport.

Definition at line 100 of file MixTransport.cpp.

getSpeciesFluxes()

void getSpeciesFluxes ( size_t  ndim, const double *const  grad_T, size_t  ldx, const double *const  grad_X, size_t  ldf, double *const  fluxes  )

overridevirtual

Get the species diffusive mass fluxes 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.

The diffusive mass flux of species k is computed from

\[ \vec{j}_k = -n M_k D_k \nabla X_k. \]

Parameters

ndim	Number of dimensions in the flux expressions
grad_T	Gradient of the temperature (length = ndim)
ldx	Leading dimension of the grad_X array (usually equal to m_nsp but not always)
grad_X	Gradients of the mole fraction. Flat vector with the m_nsp in the inner loop. length = ldx * ndim
ldf	Leading dimension of the fluxes array (usually equal to m_nsp but not always)
fluxes	Output of the diffusive mass fluxes. Flat vector with the m_nsp in the inner loop. length = ldx * ndim

Reimplemented from Transport.

Definition at line 58 of file MixTransport.cpp.

init()

void init ( ThermoPhase *  thermo, int  mode = 0, int  log_level = 0  )

overridevirtual

Initialize a transport manager.

This routine sets up a transport manager. It calculates the collision integrals and populates species-dependent data structures.

Parameters

thermo	Pointer to the ThermoPhase object
mode	Chemkin compatible mode or not. This alters the specification of the collision integrals. defaults to no.
log_level	Defaults to zero, no logging

Reimplemented from GasTransport.

Definition at line 17 of file MixTransport.cpp.

updateCond_T()

void updateCond_T ( )

protected

Update the temperature dependent parts of the species thermal conductivities.

These are evaluated from the polynomial fits of the temperature and are assumed to be independent of pressure

Definition at line 114 of file MixTransport.cpp.

Member Data Documentation

m_cond

vector<double> m_cond

protected

vector of species thermal conductivities (W/m /K)

These are used in wilke's rule to calculate the viscosity of the solution. units = W /m /K = kg m /s^3 /K. length = m_kk.

Definition at line 166 of file MixTransport.h.

m_lambda

double m_lambda = 0.0

protected

Internal storage for the calculated mixture thermal conductivity.

Units = W /m /K

Definition at line 172 of file MixTransport.h.

m_spcond_ok

bool m_spcond_ok = false

protected

Update boolean for the species thermal conductivities.

Definition at line 175 of file MixTransport.h.

m_condmix_ok

bool m_condmix_ok = false

protected

Update boolean for the mixture rule for the mixture thermal conductivity.

Definition at line 178 of file MixTransport.h.

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

• MixTransport.h
• MixTransport.cpp