ENH: alphatBoilingWallFunction: add nucleating model

ENH: Copying alphatLiquid value to alphatVapour for boiling regimes.

When using correlations for boiling regimes the phases next to the
wall are not relevant to these. Therefore the alphat is copied
accordingly from the alphat for liquid.
Only in the sub-cooling RPI model the partition of heat flux
between vapour and liquid is considered.

src/phaseSystemModels/reactingEuler/multiphaseSystem/derivedFvPatchFields/alphatWallBoilingWallFunction/alphatWallBoilingWallFunctionFvPatchScalarField.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2015-2018 OpenFOAM Foundation
-    Copyright (C) 2018 OpenCFD Ltd
+    Copyright (C) 2018-2021 OpenCFD Ltd
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -82,6 +82,10 @@ Description
     \endverbatim
 
 
+    Alternatively a correlation can be used instead of the RPI wall boiling model.
+    If the keyword nucleatingModel a model is provided the BC uses it
+    instead of the RPI model.
+
     The transition boiling regime flux (TBF) is modelled following
     a temperature based linear interpolation between the critical heat flux
     (CHF) and the minimum heat flux (MHF) in such a way that when the wall
@@ -110,12 +114,9 @@ Description
 
 
     The film boiling regime is applied when Tw is larger than TLeiden. In
-    this regime the corrlation from the filmBoilingModel is used for
+    this regime the correlation from the filmBoilingModel is used for
     calculating the cht from the wall.
 
-    The filmBoilingModel is needed in the vapor field in order to calculate
-    the heat transfer to the vapor phase in film boiling regime.
-
 
 Usage
     \table
@@ -132,8 +133,6 @@ Usage
         if phaseType 'vapor':
 
         partitioningModel|                     | yes        |
-        filmBoilingModel |                     | yes        |
-        LeidenfrostModel |                     | yes        |
 
         if phaseType 'liquid':
 
@@ -142,6 +141,7 @@ Usage
         departureDiamModel|                     | yes       |
         departureFreqModel|                     | yes       |
         K                | bubbles area constant| no       | 4
+        nucleatingModel  | nucleating Model     | no       |
 
         LeidenfrostModel |                      | no       |
         CHFModel         |                      | no       |
@@ -232,6 +232,7 @@ SourceFiles
 #include "nucleationSiteModel.H"
 #include "departureDiameterModel.H"
 #include "departureFrequencyModel.H"
+#include "nucleateFluxModel.H"
 
 #include "LeidenfrostModel.H"
 #include "filmBoilingModel.H"
@@ -248,7 +249,7 @@ namespace compressible
 {
 
 /*---------------------------------------------------------------------------*\
-            Class alphatWallBoilingWallFunctionFvPatchScalarField Declaration
+        Class alphatWallBoilingWallFunctionFvPatchScalarField Declaration
 \*---------------------------------------------------------------------------*/
 
 class alphatWallBoilingWallFunctionFvPatchScalarField
@@ -325,6 +326,10 @@ private:
             autoPtr<wallBoilingModels::departureFrequencyModel>
                 departureFreqModel_;
 
+            //- Run-time sub-cooling heat flux correlatiom
+            autoPtr<wallBoilingModels::nucleateFluxModel>
+                nucleatingModel_;
+
 
         // Film boiling model
 
@@ -353,6 +358,12 @@ private:
             //- Wetting parameter for transient boiling
             scalar wp_;
 
+            //- Use Liquid temperature at y+=250
+            bool liquidTatYplus_;
+
+            //- Face regime
+            labelField regimeTypes_;
+
 
 public:
 
@@ -454,6 +465,12 @@ public:
             return mDotL_/AbyV_;
         }
 
+        //- Return const reference to the face regime
+        const labelField& regimeTypes() const noexcept
+        {
+            return regimeTypes_;
+        }
+
         // Evaluation functions
 
             //- Update the coefficients associated with the patch field