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[1D] Add function for importing transport of electron

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This commit is contained in:
bangshiuh 2017-04-17 15:46:47 -04:00 • committed by Ray Speth
parent e2f718c65b
commit 9dd0134e31
2 changed files with 62 additions and 14 deletions
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41
include/cantera/oneD/IonFlow.h
View file

@ -17,10 +17,10 @@ namespace Cantera
* The first stage turns off the diffusion of ions due to the fast
* diffusion rate of electron without internal electric forces (ambi-
* polar diffusion effect).
*
*
* The second stage uses charge neutrality model, which assume zero charge
* flux throughout the domain, to calculate drift flux. The drift flux is
* added to the total flux of ions.
* flux throughout the domain, to calculate drift flux. The drift flux is
* added to the total flux of ions.
* Reference:
* Prager, J., U. Riedel, and J. Warnatz.
* "Modeling ion chemistry and charged species diffusion in lean
@ -29,7 +29,7 @@ namespace Cantera
*
* The third stage evaluates drift flux from electric field calculated from
* Poisson's equation, which is solved together with other equations. Poisson's
* equation is coupled because the total charge densities depends on the species'
* equation is coupled because the total charge densities depends on the species'
* concentration.
* Reference:
* Pederson, Timothy, and R. C. Brown.
@ -67,6 +67,20 @@ public:
return m_do_velocity[j];
}
/**
* Sometimes it is desired to carry out the simulation using a specified
* electron transport profile, rather than assuming it as a constant (0.4).
* Reference:
* Bisetti, Fabrizio, and Mbark El Morsli.
* "Calculation and analysis of the mobility and diffusion coefficient
* of thermal electrons in methane/air premixed flames."
* Combustion and flame 159.12 (2012): 3518-3521.
* If in the future the class GasTranport is improved, this method may
* be discard. This method specifies this profile.
*/
void setElectronTransport(vector_fp& zfixed, vector_fp& diff_e_fixed,
vector_fp& mobi_e_fixed);
protected:
virtual void updateTransport(double* x, size_t j0, size_t j1);
virtual void updateDiffFluxes(const double* x, size_t j0, size_t j1);
@ -83,6 +97,12 @@ protected:
//! flag for solving the velocity or not
std::vector<bool> m_do_velocity;
//! flag for importing transport of electron
bool m_import_electron_transport;
//! flag for overwrite transport of electron or not
bool m_overwrite_eTransport;
//! electrical properties
vector_int m_speciesCharge;
@ -92,13 +112,17 @@ protected:
//! index of neutral species
std::vector<size_t> m_kNeutral;
//! fixed transport profile of electron
vector_fp m_elecMobility;
vector_fp m_elecDiffCoeff;
//! mobility
vector_fp m_mobility;
//! solving stage
int m_stage;
//! The voltage
//! The voltage
double m_inletVoltage;
double m_outletVoltage;
@ -111,6 +135,11 @@ protected:
//! fixed velocity value
vector_fp m_fixedVelocity;
//! fixed electron transport values
vector_fp m_ztfix;
vector_fp m_diff_e_fix;
vector_fp m_mobi_e_fix;
//! The fixed electric potential value at point j
double phi_fixed(size_t j) const {
return m_fixedElecPoten[j];
@ -124,7 +153,7 @@ protected:
//! electric potential
double phi(const double* x, size_t j) const {
return x[index(c_offset_P, j)];
}
}
//! electric field
double E(const double* x, size_t j) const {

35
src/oneD/IonFlow.cpp
View file

@ -16,6 +16,8 @@ namespace Cantera
IonFlow::IonFlow(IdealGasPhase* ph, size_t nsp, size_t points) :
FreeFlame(ph, nsp, points),
m_import_electron_transport(false),
m_overwrite_eTransport(true),
m_stage(1),
m_inletVoltage(0.0),
m_outletVoltage(0.0),
@ -58,7 +60,7 @@ IonFlow::IonFlow(IdealGasPhase* ph, size_t nsp, size_t points) :
}
// no bound for electric potential
setBounds(c_offset_P, -1.0e20, 1.0e20);
m_refiner->setActive(c_offset_P, false);
m_mobility.resize(m_nsp*m_points);
m_do_poisson.resize(m_points,false);
@ -73,6 +75,8 @@ void IonFlow::resize(size_t components, size_t points){
m_do_velocity.resize(m_points,true);
m_fixedElecPoten.resize(m_points,0.0);
m_fixedVelocity.resize(m_points);
m_elecMobility.resize(m_points);
m_elecDiffCoeff.resize(m_points);
}
void IonFlow::updateTransport(double* x, size_t j0, size_t j1)
@ -81,12 +85,18 @@ void IonFlow::updateTransport(double* x, size_t j0, size_t j1)
for (size_t j = j0; j < j1; j++) {
setGasAtMidpoint(x,j);
m_trans->getMobilities(&m_mobility[j*m_nsp]);
if (m_kElectron != npos) {
m_mobility[m_kElectron+m_nsp*j] = 0.4;
m_diff[m_kElectron+m_nsp*j] = 0.4*(Boltzmann * T(x,j)) / ElectronCharge;
if (m_overwrite_eTransport && (m_kElectron != npos)) {
if (m_import_electron_transport) {
m_mobility[m_kElectron+m_nsp*j] = m_elecMobility[j];
m_diff[m_kElectron+m_nsp*j] = m_elecDiffCoeff[j];
} else {
m_mobility[m_kElectron+m_nsp*j] = 0.4;
m_diff[m_kElectron+m_nsp*j] = 0.4*(Boltzmann * T(x,j)) / ElectronCharge;
}
}
}
}
void IonFlow::updateDiffFluxes(const double* x, size_t j0, size_t j1)
{
if (m_stage == 1) {
@ -120,7 +130,7 @@ void IonFlow::frozenIonMethod(const double* x, size_t j0, size_t j1)
// flux for ions
// Set flux to zero to prevent some fast charged species (e.g. electron)
// to run away
// to run away
for (size_t k : m_kCharge) {
m_flux(k,j) = 0;
}
@ -188,7 +198,7 @@ void IonFlow::poissonEqnMethod(const double* x, size_t j0, size_t j1)
for (size_t k = 0; k < m_nsp; k++) {
m_flux(k,j) = m_wt[k]*(rho*m_diff[k+m_nsp*j]/wtm);
m_flux(k,j) *= (X(x,k,j) - X(x,k,j+1))/dz;
sum -= m_flux(k,j);
sum -= m_flux(k,j);
}
// ambipolar diffusion
@ -196,7 +206,7 @@ void IonFlow::poissonEqnMethod(const double* x, size_t j0, size_t j1)
for (size_t k : m_kCharge) {
double Yav = 0.5 * (Y(x,k,j) + Y(x,k,j+1));
double drift = rho * Yav * E_ambi
* m_speciesCharge[k] * m_mobility[k+m_nsp*j];
* m_speciesCharge[k] * m_mobility[k+m_nsp*j];
m_flux(k,j) += drift;
}
@ -395,6 +405,15 @@ void IonFlow::fixVelocity(size_t j)
}
}
void IonFlow::setElectronTransport(vector_fp& zfixed, vector_fp& diff_e_fixed,
vector_fp& mobi_e_fixed)
{
m_ztfix = zfixed;
m_diff_e_fix = diff_e_fixed;
m_mobi_e_fix = mobi_e_fixed;
m_import_electron_transport = true;
}
void IonFlow::_finalize(const double* x)
{
FreeFlame::_finalize(x);
@ -420,4 +439,4 @@ void IonFlow::_finalize(const double* x)
}
}
}
}