cantera/Cantera/src/transport/DustyGasTransport.cpp
2009-12-09 17:50:27 +00:00

282 lines
8 KiB
C++

/**
*
* @file DustyGasTransport.cpp
* Implementation file for class DustyGasTransport
*
* @ingroup transportProps
*
*/
/*
* $Author$
* $Date$
* $Revision$
*
* Copyright 2003 California Institute of Technology
* See file License.txt for licensing information
*
*/
// turn off warnings under Windows
#ifdef WIN32
#pragma warning(disable:4786)
#pragma warning(disable:4503)
#endif
#include "ThermoPhase.h"
#include "DustyGasTransport.h"
using namespace std;
/**
* Mole fractions below MIN_X will be set to MIN_X when computing
* transport properties.
*/
#define MIN_X 1.e-20
namespace Cantera {
//////////////////// class DustyGasTransport methods //////////////
DustyGasTransport::DustyGasTransport(thermo_t* thermo)
: Transport(thermo),
m_temp(-1.0),
m_porosity(0.0),
m_tortuosity(1.0),
m_pore_radius(0.0),
m_diam(0.0),
m_perm(-1.0),
m_gastran(0)
{}
void DustyGasTransport::setParameters(const int type, const int k, const doublereal* const p) {
switch(type) {
case 0:
setPorosity(p[0]); break;
case 1:
setTortuosity(p[0]); break;
case 2:
setMeanPoreRadius(p[0]); break;
case 3:
setMeanParticleDiameter(p[0]); break;
case 4:
setPermeability(p[0]); break;
default:
throw CanteraError("DustyGasTransport::init",
"unknown parameter");
}
}
void DustyGasTransport::initialize(ThermoPhase* phase, Transport* gastr) {
// constant mixture attributes
m_thermo = phase;
m_nsp = m_thermo->nSpecies();
m_tmin = m_thermo->minTemp();
m_tmax = m_thermo->maxTemp();
m_gastran = gastr;
// make a local copy of the molecular weights
m_mw.resize(m_nsp);
copy(m_thermo->molecularWeights().begin(),
m_thermo->molecularWeights().end(), m_mw.begin());
m_multidiff.resize(m_nsp, m_nsp);
m_d.resize(m_nsp, m_nsp);
m_dk.resize(m_nsp, 0.0);
m_x.resize(m_nsp);
//m_gradConc.resize(m_nsp);
//m_conc.resize(m_nsp);
// set flags all false
m_knudsen_ok = false;
m_bulk_ok = false;
// some work space
m_spwork.resize(m_nsp);
m_spwork2.resize(m_nsp);
}
/******************* binary diffusion coefficients **************/
void DustyGasTransport::updateBinaryDiffCoeffs() {
if (m_bulk_ok) return;
int n,m;
// get the gaseous binary diffusion coefficients
m_gastran->getBinaryDiffCoeffs(m_nsp, m_d.ptrColumn(0));
doublereal por2tort = m_porosity / m_tortuosity;
for (n = 0; n < m_nsp; n++)
for (m = 0; m < m_nsp; m++)
m_d(n,m) *= por2tort;
m_bulk_ok = true;
}
void DustyGasTransport::updateKnudsenDiffCoeffs() {
if (m_knudsen_ok) return;
doublereal K_g = m_pore_radius * m_porosity / m_tortuosity;
const doublereal TwoThirds = 2.0/3.0;
for (int k = 0; k < m_nsp; k++) {
m_dk[k] = TwoThirds * K_g * sqrt((8.0 * GasConstant * m_temp)/
(Pi * m_mw[k]));
}
m_knudsen_ok = true;
}
void DustyGasTransport::eval_H_matrix() {
updateBinaryDiffCoeffs();
updateKnudsenDiffCoeffs();
int k,l,j;
doublereal sum;
for (k = 0; k < m_nsp; k++) {
// evaluate off-diagonal terms
for (l = 0; l < m_nsp; l++) m_multidiff(k,l) = -m_x[k]/m_d(k,l);
// evaluate diagonal term
sum = 0.0;
for (j = 0; j < m_nsp; j++) if (j != k) sum += m_x[j]/m_d(k,j);
m_multidiff(k,k) = 1.0/m_dk[k] + sum;
}
}
// void DustyGasTransport::getMolarFluxes(const double* grad_conc,
// double grad_P, double* fluxes) {
// updateMultiDiffCoeffs();
// copy(grad_conc, grad_conc + m_nsp, m_spwork.begin());
// multiply(m_multidiff, m_spwork.begin(), fluxes);
// m_thermo->getConcentrations(m_spwork.begin());
// divide_each(m_spwork.begin(), m_spwork.end(), m_dk.begin());
// // if no permeability has been specified, use result for
// // close-packed spheres
// double b = 0.0;
// if (m_perm < 0.0) {
// double p = m_porosity;
// double d = m_diam;
// double t = m_tortuosity;
// b = p*p*p*d*d/(72.0*t*(1.0-p)*(1.0-p));
// }
// else {
// b = m_perm;
// }
// b *= grad_P / m_gastran->viscosity();
// scale(m_spwork.begin(), m_spwork.end(), m_spwork.begin(), b);
// increment(m_multidiff, m_spwork.begin(), fluxes);
// scale(fluxes, fluxes + m_nsp, fluxes, -1.0);
// }
void DustyGasTransport::getMolarFluxes(const doublereal* state1,
const doublereal* state2, double delta, double* fluxes) {
int k;
doublereal conc1, conc2;
doublereal* cbar = DATA_PTR(m_spwork);
doublereal* gradc = DATA_PTR(m_spwork2);
doublereal t1 = state1[0];
doublereal t2 = state2[0];
doublereal rho1 = state1[1];
doublereal rho2 = state2[1];
const doublereal* y1 = state1 + 2;
const doublereal* y2 = state2 + 2;
doublereal c1sum = 0.0, c2sum = 0.0;
for (k = 0; k < m_nsp; k++) {
conc1 = rho1*y1[k]/m_mw[k];
conc2 = rho2*y2[k]/m_mw[k];
cbar[k] = 0.5*(conc1 + conc2);
gradc[k] = (conc2 - conc1)/delta;
c1sum += conc1;
c2sum += conc2;
}
doublereal p1 = c1sum * GasConstant * state1[0];
doublereal p2 = c2sum * GasConstant * state2[0];
doublereal pbar = 0.5*(p1 + p2);
doublereal gradp = (p2 - p1)/delta;
doublereal tbar = 0.5*(t1 + t2);
m_thermo->setState_TPX(tbar, pbar, cbar);
updateMultiDiffCoeffs();
multiply(m_multidiff, gradc, fluxes);
divide_each(cbar, cbar + m_nsp, m_dk.begin());
// if no permeability has been specified, use result for
// close-packed spheres
double b = 0.0;
if (m_perm < 0.0) {
double p = m_porosity;
double d = m_diam;
double t = m_tortuosity;
b = p*p*p*d*d/(72.0*t*(1.0-p)*(1.0-p));
}
else {
b = m_perm;
}
b *= gradp / m_gastran->viscosity();
scale(cbar, cbar + m_nsp, cbar, b);
increment(m_multidiff, cbar, fluxes);
scale(fluxes, fluxes + m_nsp, fluxes, -1.0);
}
void DustyGasTransport::updateMultiDiffCoeffs() {
// see if temperature has changed
updateTransport_T();
// update the mole fractions
updateTransport_C();
eval_H_matrix();
// invert H
int ierr = invert(m_multidiff);
if (ierr != 0) {
throw CanteraError("DustyGasTransport::updateMultiDiffCoeffs",
"invert returned ierr = "+int2str(ierr));
}
}
void DustyGasTransport::getMultiDiffCoeffs(const int ld, doublereal* const d) {
int i,j;
updateMultiDiffCoeffs();
for (i = 0; i < m_nsp; i++) {
for (j = 0; j < m_nsp; j++) {
d[ld*j + i] = m_multidiff(i,j);
}
}
}
/**
* Update temperature-dependent quantities.
*/
void DustyGasTransport::updateTransport_T()
{
if (m_temp == m_thermo->temperature()) return;
m_temp = m_thermo->temperature();
m_knudsen_ok = false;
m_bulk_ok = false;
}
void DustyGasTransport::updateTransport_C()
{
m_thermo->getMoleFractions(DATA_PTR(m_x));
// add an offset to avoid a pure species condition
// (check - this may be unnecessary)
int k;
for (k = 0; k < m_nsp; k++) {
m_x[k] = fmaxx(MIN_X, m_x[k]);
}
}
}