properties.h

Cantera Properties

Cantera Properties

We compute the material properties of a mixture using the Cantera library.

#include "cantera/cantera.h"
#include "variable-properties.h"

#define VARIABLE_PROPERTIES 1

Properties Functions

Functions for the update of the density, given the thermodynamic state.

cantera_gasprop_density(): gas phase density according to the ideal gas low

// fixme: check discrepancy between ideal gas and `thermo_density()`
double cantera_gasprop_density (void * p) {
  ThermoState * ts = (ThermoState *)p;
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  size_t ns = thermo_nSpecies (thermo);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);
  //return thermo_density (thermo);
  double MWmix = thermo_meanMolecularWeight (thermo);
  return ts->P*MWmix / (R_GAS*1e3*ts->T);
}

cantera_gasprop_viscosity(): gas phase dynamic viscosity

double cantera_gasprop_viscosity (void * p) {
  ThermoState * ts = (ThermoState *)p;
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  size_t ns = thermo_nSpecies (thermo);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);
  return trans_viscosity (tran);
}

cantera_gasprop_thermalconductivity(): gas phase thermal conductivity

double cantera_gasprop_thermalconductivity (void * p) {
  ThermoState * ts = (ThermoState *)p;
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  size_t ns = thermo_nSpecies (thermo);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);
  return trans_thermalConductivity (thermo);
}

cantera_gasprop_heatcapacity(): gas phase specific heat capacity

double cantera_gasprop_heatcapacity (void * p) {
  ThermoState * ts = (ThermoState *)p;
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  size_t ns = thermo_nSpecies (thermo);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);
  return thermo_cp_mass (thermo);
}

cantera_gasprop_heatcapacity_species(): gas phase species heat capacity

void cantera_gasprop_heatcapacity_species (void * p, double * r) {
  ThermoState * ts = (ThermoState *)p;
  size_t ns = thermo_nSpecies (thermo);
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);

  thermo_getPartialMolarCp (thermo, ns, r);

  double MW[ns];
  thermo_getMolecularWeights (thermo, ns, MW);

  for (int i = 0; i < ns; i++)
    r[i] /= MW[i];
}

cantera_gasprop_diff(): diffusion coefficient of a species in gas phase

void cantera_gasprop_diff (void * p, double * r) {
  ThermoState * ts = (ThermoState *)p;
  size_t ns = thermo_nSpecies (thermo);
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  double xm[ns];
  for (int i = 0; i < ns; i++)
    xm[i] = max (ts->x[i], 1e-10);
  thermo_setMoleFractions (thermo, ns, xm, 1);
  trans_getMixDiffCoeffs (tran, ns, r);
}

cantera_antoine(): implementation of the antoine function using opensmoke

double cantera_antoine (double T, double P, int i) {
  return 0.;
}

cantera_gasprop_thermal_expansion(): gas thermal expansion coefficient

double cantera_gasprop_thermal_expansion (const void * p, void * s) {
  ThermoState * ts = (ThermoState *)s;
  return (ts->T > 0.) ? 1./ts->T : 0.;
}

cantera_gasprop_species_expansion(): gas species expansion coefficient

void cantera_gasprop_species_expansion (const void * p, void * s, double * r) {
  ThermoState * ts = (ThermoState *)s;
  thermo_setTemperature (thermo, ts->T);
  thermo_setPressure (thermo, ts->P);
  size_t ns = thermo_nSpecies (thermo);
  thermo_setMoleFractions (thermo, ns, ts->x, 1);
  double MWmix = thermo_meanMolecularWeight (thermo);

  double MW[ns];
  thermo_getMolecularWeights (thermo, ns, MW);

  for (int i = 0; i < ns; i++)
    r[i] = MWmix / MW[i];
}

cantera_liqprop_thermal_expansion(): liq thermal expansion coefficient

double cantera_liqprop_thermal_expansion (const void * p, void * s) {
  ThermoProps * tp = (ThermoProps *)p;
  ThermoState * ts = (ThermoState *)s;

  double epsT = 1.e-3;
  double Ttop = ts->T + epsT, Tbot = ts->T - epsT;
  ThermoState tstop, tsbot;
  tstop.T = Ttop, tstop.P = ts->P, tstop.x = ts->x;
  tsbot.T = Tbot, tsbot.P = ts->P, tsbot.x = ts->x;
  double rhotop = tp->rhov (&tstop), rhobot = tp->rhov (&tsbot);
  double rhoval = tp->rhov (ts);
  return (rhoval > 0.) ? -1./rhoval*(rhotop - rhobot)/(2.*epsT) : 0.;
}

cantera_liqprop_species_expansion(): liq species expansion coefficient

void cantera_liqprop_species_expansion (const void * p, void * s, double * r)
{
  for (unsigned int i = 0; i < thermo_nSpecies (thermo_liq); i++)
    r[i] = 0.;
}

Thermodynamic Properties

We create the instance of two structures with the thermodynamic properties, tp1 for the liquid phase and tp2 for the gas phase. The same nomenclature is used for the thermodynamic states.

ThermoProps tp1, tp2;

Initialization

We set the thermodynamic properties function pointers to the specific opensmoke functions declared above.

event defaults (i = 0) {

We set the thermodynamic properties functions to the correct opensmoke functions that compute material properties.

  tp1.rhov    = NULL;
  tp1.muv     = NULL;
  tp1.lambdav = NULL;
  tp1.cpv     = NULL;
  tp1.dhev    = NULL;
  tp1.diff    = NULL;
  tp1.cps     = NULL;
  tp1.sigmas  = NULL;
  tp1.betaT   = cantera_liqprop_thermal_expansion;
  tp1.betaY   = cantera_liqprop_species_expansion;

  tp2.rhov    = cantera_gasprop_density;
  tp2.muv     = cantera_gasprop_viscosity;
  tp2.lambdav = cantera_gasprop_thermalconductivity;
  tp2.cpv     = cantera_gasprop_heatcapacity;
  tp2.diff    = cantera_gasprop_diff;
  tp2.cps     = cantera_gasprop_heatcapacity_species;
  tp2.betaT   = cantera_gasprop_thermal_expansion;
  tp2.betaY   = cantera_gasprop_species_expansion;
}