PEM water electrolyzer cell application

This is a test case for proton exchange membrane / polymer water electrolyzer cell.

Chemical reaction:

Anode side: $\Large \textrm{H}_{2}\textrm{O}\to\textrm{2H}^{+}+\textrm{0.5O}_{2}+\textrm{2e}^{-}$
Cathode side: $\Large \textrm{2H}^{+}+\textrm{2e}^{-}\to\textrm{H}_{2}$
Overall Reaction: $\Large \textrm{H}_{2}\textrm{O}\to\textrm{H}_{2}+\textrm{0.5O}_{2}$

The water may exist in vapor and liquid in PEM water electrolyzer cells

Operating conditions

```none
Temperature:            313 K, 40 oC
Pressure:               1 bar/1 bar (anode/cathode)
supply:                 liquid water
Active area             0.8 cm2

Mean current density    8000 A/m3
```
  

To run the case:

In serial

  # Generate the meshes with 'blockMesh'
  make mesh
  # or Generate the meshes with 'salome'
  # make salomeMesh

  # Run in serial
  make srun

  

In parallel

  # Generate the meshes with 'blockMesh'
  make mesh
  # or Generate the meshes with 'salome'
  # make salomeMesh

  # Edit values of 'nx' and 'ny' in constant/cellProperties

  export NPROCS=nx*ny # (value of 'nx' times 'ny')

  # Generate the cellID
  # For manual decomposition
  make decompose

  # Decomposition for multiple regions
  make parallel

  # Run in parallel
  make run  #( the value of 'nx' times 'ny' needs to be changed in 'Makefile')
  # or
  # mpirun -np nx*ny fuelCell0Foam -parallel -fileHandler collated | tee log.run

  

To view the result:

In serial

Residual plot
```
make plot
#or
gnuplot ResidualPlot
```
Simulation results
```
make view
paraview
```

In parallel

Residual plot
```
make plot
or
gnuplot ResidualPlot
```
Simulation results
```
make reconstruct
make view
paraview
```