reactingEulerFoam: alphatWallBoilingWallFunction: Updated documentation and stabilised a division

Patch contributed by Juho Peltola, VTT.

applications/solvers/multiphase/reactingEulerFoam/derivedFvPatchFields/alphatWallBoilingWallFunction/alphatWallBoilingWallFunctionFvPatchScalarField.C

@@ -605,7 +605,11 @@ void alphatWallBoilingWallFunctionFvPatchScalarField::updateCoeffs()
                 // Quenching heat transfer coefficient
                 const scalarField hQ
                 (
-                    2*(alphaw*Cpw)*fDep*sqrt((0.8/fDep)/(pi*alphaw/rhoLiquidw))
+                    2*(alphaw*Cpw)*fDep
+                   *sqrt
+                    (
+                        (0.8/max(fDep, small))/(pi*alphaw/rhoLiquidw)
+                    )
                 );
 
                 // Quenching heat flux

applications/solvers/multiphase/reactingEulerFoam/derivedFvPatchFields/alphatWallBoilingWallFunction/alphatWallBoilingWallFunctionFvPatchScalarField.H

@@ -33,9 +33,9 @@ Description
       - bubble departure diameter
 
     Implements a version of the well-known RPI wall boiling model
-    (Kurul & Podowski, 1991). The model implementation is similar to the model
-    described by Peltola & Pättikangas (2012) but has been extended with the
-    wall heat flux partitioning models.
+    (Kurul & Podowski, 1991). The model implementation is described in Peltola
+    et al. (2019) and is similar to the model described by Peltola &
+    Pättikangas (2012).
 
     References:
     \verbatim
@@ -46,6 +46,14 @@ Description
         ISBN: 0-89448-162-1, pp. 30-40.
     \endverbatim
 
+    \verbatim
+        Peltola, J., Pättikangas, T., Bainbridge, W., Lehnigk, R., Schlegel, F.
+        (2019).
+        On Development and validation of subcooled nucleate boiling models for
+        OpenFOAM Foundation Release.
+        NURETH-18 Conference Proceedings, Portland, Oregon, United States, 2019.
+    \endverbatim
+
     \verbatim
         Peltola, J., & Pättikangas, T.J.H. (2012).
         Development and validation of a boiling model for OpenFOAM multiphase
@@ -73,9 +81,9 @@ Usage
         if phaseType 'liquid':
 
         partitioningModel|                     | yes         |
-        nucleationSiteModel|                     | yes         |
-        departureDiamModel|                     | yes         |
-        departureFreqModel|                     | yes         |
+        nucleationSiteModel|                   | yes         |
+        departureDiamModel|                    | yes         |
+        departureFreqModel|                    | yes         |
     \endtable
 
     NOTE: Runtime selectabale submodels may require model specific entries
@@ -90,7 +98,7 @@ Usage
         Cmu             0.09;
         kappa           0.41;
         E               9.8;
-        relax           0.001;
+        relax           0.1;
         dmdt            uniform 0;
         partitioningModel
         {