CFD Online Discussion Forums - Pyrolysis Model

The Equation can be written as follow in a new file TEqn.H....This file can be created in solver directory using touch TEqn.H

Code:

        fvScalarMatrix TEqn

    (

        fvm::ddt(T) == fvm::laplacian(alphat, T)

     );



TEqn.solve();

But before this we have to define alphat as

Code:

tmp <volScalarField> alphat = K/(rho*cp);

Now as k is dependent on vertical length, we need to access that coordinate using

Code:

const fvMesh& mesh = U.mesh();

volScalarField Ycord = mesh.C().component(vector::Y);// assuming Y is the vertical



         forAll(K,celli)

{

                if (Ycord[celli] <= DU.value())

        

                {

                        K[celli] = Keff.value()/(rho.value()*cp.value());

                }

                else

                {

                        K[celli] = K2.value()/(rho.value()*cp.value());;

                }



}

And finally we have to intialise all the additional variables in createFields.H as

Code:

    // Density

    dimensionedScalar rho(transportProperties.lookup("rho"));

    

    // sPECIFIC HEAT

    dimensionedScalar cp(transportProperties.lookup("cp"));



    // Threshold vertical length 

    dimensionedScalar DU(transportProperties.lookup("DU"));

    

      // Keff

    dimensionedScalar Keff(transportProperties.lookup("Keff"));

    

      // K2

    dimensionedScalar K2(transportProperties.lookup("K2"));



 Info<< "Reading field Thermal Conductivity \n" << endl;

volScalarField K

(

    IOobject

    (

        "K",

        runTime.timeName(),

        mesh,

        IOobject::NO_READ,

        IOobject::AUTO_WRITE

    ),

    mesh

);

Finally, include "TEqn.H" in your "customFoam.C" file within runtime loop