multiphaseEuler: Added Prandtl heat transfer model

This simple model creates a heat transfer coefficient in proportion with
the corresponding drag model's momentum transfer coefficient. A
user-defined Prandtl number and a harmonic average of the phases'
specific heats are used to specify the constant of proportionality.

This model has no physical basis. It exists primarily for testing
purposes. It has the advantage of being applicable to any interface,
including those representing segregated configurations.

Example usage:

    heatTransfer
    {
        gas_segregatedWith_liquid
        {
            type            Prandtl;
            Pr              0.7;
        }
    }

applications/modules/multiphaseEuler/interfacialModels/Make/files

@@ -44,6 +44,7 @@ heatTransferModels/Gunn/Gunn.C
 heatTransferModels/sphericalHeatTransfer/sphericalHeatTransfer.C
 heatTransferModels/nonSphericalHeatTransfer/nonSphericalHeatTransfer.C
 heatTransferModels/timeScaleFilteredHeatTransfer/timeScaleFilteredHeatTransfer.C
+heatTransferModels/Prandtl/Prandtl.C
 
 virtualMassModels/virtualMassModel/virtualMassModel.C
 virtualMassModels/virtualMassModel/virtualMassModelNew.C

applications/modules/multiphaseEuler/interfacialModels/heatTransferModels/Prandtl/Prandtl.C

@@ -0,0 +1,90 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2023 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "Prandtl.H"
+#include "dragModel.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace heatTransferModels
+{
+    defineTypeNameAndDebug(Prandtl, 0);
+    addToRunTimeSelectionTable
+    (
+        heatTransferModel,
+        Prandtl,
+        dictionary
+    );
+}
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::heatTransferModels::Prandtl::Prandtl
+(
+    const dictionary& dict,
+    const phaseInterface& interface,
+    const bool registerObject
+)
+:
+    heatTransferModel(dict, interface, registerObject),
+    interfacePtr_(interface.clone()),
+    interface_(interfacePtr_()),
+    Pr_("Pr", dimless, dict)
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::heatTransferModels::Prandtl::~Prandtl()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+Foam::tmp<Foam::volScalarField>
+Foam::heatTransferModels::Prandtl::K
+(
+    const scalar residualAlpha
+) const
+{
+    const dragModel& drag =
+        interface_.fluid().lookupInterfacialModel<dragModel>(interface_);
+
+    const volScalarField CpAvg
+    (
+        interface_.thermo1().Cp()*interface_.thermo2().Cp()
+       /(interface_.thermo1().Cp() + interface_.thermo2().Cp())
+    );
+
+    return drag.K()*CpAvg/Pr_;
+}
+
+
+// ************************************************************************* //

applications/modules/multiphaseEuler/interfacialModels/heatTransferModels/Prandtl/Prandtl.H

@@ -0,0 +1,123 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2023 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::heatTransferModels::Prandtl
+
+Description
+    This simple model creates a heat transfer coefficient in proportion with
+    the corresponding drag model's momentum transfer coefficient. A
+    user-defined Prandtl number and a harmonic average of the phases'
+    specific heats are used to specify the constant of proportionality.
+
+    This model has no physical basis. It exists primarily for testing
+    purposes. It has the advantage of being applicable to any interface,
+    including those representing segregated configurations.
+
+    Example usage:
+    \verbatim
+    heatTransfer
+    {
+        gas_segregatedWith_liquid
+        {
+            type            Prandtl;
+            Pr              0.7;
+        }
+    }
+    \endverbatim
+
+SourceFiles
+    Prandtl.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Prandtl_H
+#define Prandtl_H
+
+#include "heatTransferModel.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace heatTransferModels
+{
+
+/*---------------------------------------------------------------------------*\
+                            Class Prandtl Declaration
+\*---------------------------------------------------------------------------*/
+
+class Prandtl
+:
+    public heatTransferModel
+{
+    // Private Data
+
+        //- Interface pointer
+        const autoPtr<phaseInterface> interfacePtr_;
+
+        //- Interface
+        const phaseInterface& interface_;
+
+        //- Prandtl number
+        const dimensionedScalar Pr_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("Prandtl");
+
+
+    // Constructors
+
+        //- Construct from a dictionary and an interface
+        Prandtl
+        (
+            const dictionary& dict,
+            const phaseInterface& interface,
+            const bool registerObject
+        );
+
+
+    //- Destructor
+    virtual ~Prandtl();
+
+
+    // Member Functions
+
+        //- The heat transfer function K used in the enthalpy equation
+        tmp<volScalarField> K(const scalar residualAlpha) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace heatTransferModels
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //