Designing the large-format cell
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Some preliminary CFD of the simplified flow frame (U in m/s and P in Pa if I understand OpenFOAM correctly)
Conditions
- 4 L/min volumetric flowrate through one half-cell, inlet is on the top left, outlet on the lower right.
- Ambient pressure on cell outlet
- No-slip wall
- File containing CAD and CFD simulation setup is here
Blue is inlet, red outlet, pink is porous zone
!
Close-up of mesh:
Flow Distribution (m/s)
Pletcher and Walsh say a range of 0.05-0.4 m/s linear velocity is a good design range for electrolyte flow, if I apply a smaller range for velocity with 0.05 m/s as the upper limit, we see which areas in red have sufficient flow and where the dead zones are (in the corners, predictably)
Pressure Drop (Pa)
Big Caveat
Still need to calculate the Darcy-Forchheimer coefficients to do the porous zone simulation in the graphite felt, right now I am using the default values, which are almost certainly not correct. If anyone feels like finding that data (https://openfoamwiki.net/index.php/DarcyForchheimer). I think Antoni Forner-Cuenca's group has measured a lot on this recently. This could change the results quite a bit as far as flow distribution and pressure drop. I've mostly so far just been getting familiar with the simulation pipeline in FreeCAD --> CfdOF --> OpenFOAM --> ParaView.
Design is far from final, and I'm probably doing the CFD incorrectly, BUT it prints and doesn't leak! We will keep optimizing the flow frame later.
