combustionModels: Added Qdot function object

This function object writes out the heat release rate field for a
combustion model. This is useful for solvers where combustion is
optional, and which do not therefore write out the heat release rate by
default; e.g., chtMultiRegionFoam and reactingTwoPhaseEulerFoam.

tutorials/heatTransfer/chtMultiRegionFoam/reverseBurner/0/gas/epsilon

@@ -17,7 +17,7 @@ FoamFile
 
 dimensions      [ 0 2 -3 0 0 0 0 ];
 
-internalField   uniform 1.27351e-06;
+internalField   uniform 3.60203e-06;
 
 boundaryField
 {

tutorials/heatTransfer/chtMultiRegionFoam/reverseBurner/0/gas/k

@@ -17,7 +17,7 @@ FoamFile
 
 dimensions      [ 0 2 -2 0 0 0 0 ];
 
-internalField   uniform 8.4375e-05;
+internalField   uniform 0.00016875;
 
 boundaryField
 {

tutorials/heatTransfer/chtMultiRegionFoam/reverseBurner/system/Qdot

@@ -0,0 +1,17 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Calculates the heat release rate Qdot, outputting the data as a Qdot field.
+
+\*---------------------------------------------------------------------------*/
+
+#includeEtc "caseDicts/postProcessing/combustion/Qdot.cfg"
+
+region gas;
+
+// ************************************************************************* //

tutorials/heatTransfer/chtMultiRegionFoam/reverseBurner/system/controlDict

@@ -51,5 +51,10 @@ maxDi           5.0;
 
 adjustTimeStep  yes;
 
+functions
+{
+    #includeFunc Qdot
+}
+
 
 // ************************************************************************* //