Merge branch 'fix/biomineralizationReactionsREADME' into 'master'

[dumux-course] [biomin] Expand on reaction equations in the biomin README.md for clarity

See merge request !110

exercises/exercise-biomineralization/README.md

@@ -57,15 +57,27 @@ Note, that the urease concentration $`\displaystyle Z_{urease,biofilm}`$ has a k
 
 $`\displaystyle Z_{urease,biofilm} = k_{urease,biofilm} * mass_{biofilm}`$
 
-The last step is defining the source term for each component according to the chemical equation:
+The last step is defining the source term for each component according to the chemical reaction equations:
 
-$`\displaystyle Ca^{2+} + CO(NH)_{2} + 2 H_{2}O -> 2 NH_{4}^{+} + CaCO_{3}`$
+$`\displaystyle CO(NH_{2})_{2} + 2 H_{2}O -> 2 NH_{3} + H_{2}CO_{3}`$
 
-which is:
+$`\displaystyle Ca^{2+} + CO_{3}^{2-} -> CaCO_{3}`$
 
-Calcium ion + Urea + 2 Water → 2 Ammonium ions + Calcite
+Or the total chemical reaction equation, in which the appearence of inorganic carbon species cancels out:
+
+$`\displaystyle Ca^{2+} + CO(NH_{2})_{2} + 2 H_{2}O -> 2 NH_{4}^{+} + CaCO_{3}`$
+
+which, written in terms of our primary variables are:
+
+Urea + 2 Water → (2 Ammonia) + Total Carbon
+
+Calcium ion + Total Carbon → Calcite
+
+Calcium ion + Urea + 2 Water → (2 Ammonium ions) + Calcite
 
 Note that since the chemistry is simplified for this dumux-course example, the component Ammonium is neglected and you thus cannot set its source term, even though it is produced in the real reaction.
+Similarly, we only account for "Total Carbon", which is the sum of all carbon species
+($`CO_{2}`$, $`H_{2}CO_{3}`$, $`HCO_{3}^{-}`$, and $`CO_{3}^{2-}`$).
 
 ### 3. Make use of your newly created chemical equation
 

exercises/exercise-biomineralization/params.input

@@ -17,8 +17,8 @@ InitPressure = 1e5 # [Pa] initial pressure
 InitBiofilm = 0.05 # [-] initial volumefraction biofilm
 
 [Injection]
-InjVolumeflux = 1e-4 # [m³/s] = [ml/min] /[s/min] /[ml/m³]
-InjBioTime = 12 # [days]
+InjVolumeflux = 1e-5 # [m³/s] = [ml/min] /[s/min] /[ml/m³]
+InjBioTime = 10 # [days]
 InjCO2 = 1e-2 # [kg/s] gasFlux
 ConcCa = 40 # [kg/m³] injected calcium concentration (max: 50)
 ConcUrea = 60 # [kg/m³] injected urea concentration (max: 80)