[sm0226]

Hi OpenFOAMers!!

I am looking for the way to set the thermophysiclProperties for wet hydrogen premixed combustion. (H2 + Air + Steam)

If I set the mixture type to homogeneousMixture, only can set the category for reactants and products. (not fuel - oxidant - burntProducts)
As like tutorials/combustion/XiFoam/RAS/moriyoshiHomogeneous/constant/thermophysiclProperties

For this, how to calculate molWeight for reactants and products for this mixture (10% H2 + 65% Air + 25% Steam)??

(I`m very sorry about not attach example thermophysiclProperties file.)

[ugata88]

Originally Posted by sm0226

Hi OpenFOAMers!!

I am looking for the way to set the thermophysiclProperties for wet hydrogen premixed combustion. (H2 + Air + Steam)

If I set the mixture type to homogeneousMixture, only can set the category for reactants and products. (not fuel - oxidant - burntProducts)
As like tutorials/combustion/XiFoam/RAS/moriyoshiHomogeneous/constant/thermophysiclProperties

For this, how to calculate molWeight for reactants and products for this mixture (10% H2 + 65% Air + 25% Steam)??

(I`m very sorry about not attach example thermophysiclProperties file.)

Hi,

I am also suffering from a similar situation. I want to burn 90% methane - 10% hydrogen gas mixture as pre-mixed by enriching oxygen at different rates. Equivalence ratio 0,7 and Su is constant

The reactants consist of 90% methane - 10% hydrogen, air and additional oxygen gas.


How can I determine lower, upper and common temperature values and high temperature coeff and low temperature coeff values for reactants and products?

I couldn't figure out how to create thermo properties in the constant/thermophysicalProperties directory in XiFoam solver.

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object thermophysicalProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

thermoType
{
type heheuPsiThermo;
mixture homogeneousMixture;
transport sutherland;
thermo janaf;
equationOfState perfectGas;
specie specie;
energy absoluteEnthalpy;
}

stoichiometricAirFuelMassRatio
stoichiometricAirFuelMassRatio [0 0 0 0 0 0 0] ???????;

reactants
{
specie
{
nMoles ?????;
molWeight ?????;
}
thermodynamics
{
Tlow ???;
Thigh ????;
Tcommon ????;
highCpCoeffs
(
?????????????
);
lowCpCoeffs
(
????????????
);
}
transport
{

As 1.67212e-06;
Ts 170.672;
}
}

products
{
specie
{
nMoles 1;
molWeight ?????;
}
thermodynamics
{
Tlow ???;
Thigh ????;
Tcommon ????;
highCpCoeffs
(
?????????????
);
lowCpCoeffs
(
?????????????
);
}
transport
{
As 1.67212e-06;
Ts 170.672;
}
}


//

[casseer15]

Originally Posted by ugata88

Hi,

I am also suffering from a similar situation. I want to burn 90% methane - 10% hydrogen gas mixture as pre-mixed by enriching oxygen at different rates. Equivalence ratio 0,7 and Su is constant

The reactants consist of 90% methane - 10% hydrogen, air and additional oxygen gas.


How can I determine lower, upper and common temperature values and high temperature coeff and low temperature coeff values for reactants and products?

I couldn't figure out how to create thermo properties in the constant/thermophysicalProperties directory in XiFoam solver.

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object thermophysicalProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

thermoType
{
type heheuPsiThermo;
mixture homogeneousMixture;
transport sutherland;
thermo janaf;
equationOfState perfectGas;
specie specie;
energy absoluteEnthalpy;
}

stoichiometricAirFuelMassRatio
stoichiometricAirFuelMassRatio [0 0 0 0 0 0 0] ???????;

reactants
{
specie
{
nMoles ?????;
molWeight ?????;
}
thermodynamics
{
Tlow ???;
Thigh ????;
Tcommon ????;
highCpCoeffs
(
?????????????
);
lowCpCoeffs
(
????????????
);
}
transport
{

As 1.67212e-06;
Ts 170.672;
}
}

products
{
specie
{
nMoles 1;
molWeight ?????;
}
thermodynamics
{
Tlow ???;
Thigh ????;
Tcommon ????;
highCpCoeffs
(
?????????????
);
lowCpCoeffs
(
?????????????
);
}
transport
{
As 1.67212e-06;
Ts 170.672;
}
}


//

Hope you found the answer. If not drop me an email at casseer15@gmail.com

[casseer15]

For anyone who are still looking for an answer, How you calculate the molWeight is,


molWeight = ΣWiXi, where Wi is molar weight of individual species and Xi is mol fraction of that species.


To find the janaf coefficients, you can use databases from GRI MEch or Burcats. These databases have the 14 coefficients listed. (They will have 15 coefficients, disregard the last one of third row). They are in 3 rows, don't be afraid, its just one row after the other. The 1st 7 are highCp and the next 7 are lowCp.



Find the coefficients for individual species from these files and use a similar calculation to above to find the JANAF coefficients for a mixture.



The Thigh qnd Tlow a should be at the begining of each element in these files (ie 200.000 6000.000).



You can also use adiabaticFlame T to calculate the janaf coefficients.
Type

cd $FOAM_UTILITIES/thermophysical/adiabaticFlameT


then
adiabaticFlameT controlDict


you will get a file with data for each stoicheometric ratio calcualted.


By default, controlDict has selected values for H2.

the lines
$H2;
// $CH4;
// $PROPANE;
specieis the fuel in this.