multiphaseEuler: Reinstated multicomponentIsothermalPhaseModel

This phase model solves multiple physical species, but fixes the
temperature to a constant value. This combination does not conserve
the energy of the phase.

applications/modules/multiphaseEuler/phaseSystem/phaseModels/IsothermalPhaseModel/IsothermalPhaseModel.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2015-2023 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2015-2024 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -87,6 +87,14 @@ Foam::IsothermalPhaseModel<BasePhaseModel>::kappaEff(const label patchi) const
 }
 
 
+template<class BasePhaseModel>
+Foam::tmp<Foam::fvScalarMatrix>
+Foam::IsothermalPhaseModel<BasePhaseModel>::divj(volScalarField& Yi) const
+{
+    return tmp<fvScalarMatrix>(new fvScalarMatrix(Yi, dimMass/dimTime));
+}
+
+
 template<class BasePhaseModel>
 Foam::tmp<Foam::fvScalarMatrix>
 Foam::IsothermalPhaseModel<BasePhaseModel>::heEqn()

applications/modules/multiphaseEuler/phaseSystem/phaseModels/IsothermalPhaseModel/IsothermalPhaseModel.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2015-2023 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2015-2024 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -81,6 +81,10 @@ public:
         //- Return the effective thermal conductivity on a patch
         virtual tmp<scalarField> kappaEff(const label patchi) const;
 
+        //- Return the source term for the given specie mass-fraction
+        //  equation
+        virtual tmp<fvScalarMatrix> divj(volScalarField& Yi) const;
+
         //- Return the enthalpy equation
         virtual tmp<fvScalarMatrix> heEqn();
 };

applications/modules/multiphaseEuler/phaseSystem/phaseModels/phaseModels.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2015-2023 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2015-2024 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -200,6 +200,34 @@ namespace Foam
         multiComponentPhaseModel
     );
 
+    typedef
+        MulticomponentPhaseModel
+        <
+            IsothermalPhaseModel
+            <
+                InertPhaseModel
+                <
+                    MovingPhaseModel
+                    <
+                        ThermoPhaseModel
+                        <
+                            phaseModel,
+                            rhoFluidMulticomponentThermo
+                        >
+                    >
+                >
+            >
+        >
+        multicomponentIsothermalPhaseModel;
+
+    addNamedToRunTimeSelectionTable
+    (
+        phaseModel,
+        multicomponentIsothermalPhaseModel,
+        phaseSystem,
+        multicomponentIsothermalPhaseModel
+    );
+
     typedef
         MulticomponentPhaseModel
         <