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Simulation of the Gas Channel in a Polymer Electrolyte Fuel Cell
Supervision:
Background:
Fuel cells transform chemical into electrical power with a high degree of efficiency. A variety of different types based on different
chemical reactions exists. The most famous type is the proton exhange membrane (PEM) fuel cell which turns hydrogen and oxygen into water
using a polymer membrane as electrolyte.
A PEM fuel cell consists of several layers: Its heart is represented by a membrane which is permeable only for protons but not for electrons.
At each side of the membrane there is an electrode. A metal plate with incorporated channels leads the gas to the reaction zone. At the anode
hydrogen is split into protons and electrons. The protons can pass the membrane whereas the electrons have to take the detour via the wires
and the load. At the cathode side they recombine and reduce the oxygen of the inflown air to water.
The efficiency in electrical power of a fuel cell relies on the unhindered reaction described above. Too much liquid water in the porous
materials can interfere the inflow of oxygen and thus reduce the efficiency. Therefore, special hydrophobe coatings of the materials try
to evacuate the water from the reaction zone.
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Schematic of a PEM fuel cell
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Image from: Rensink, Roth, Fell, Proceedings of 6th ICNMM, 2008
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Tasks:
The hydrophobic coating presses the water out in the gas channel. The inflowing gas ought to transport the water out of the fuel cell.
In order to optimize the channel geometry, the breakaway of the drops is to be simulated by means of the lattice Boltzmann method.
Therefor an already implemented two-phase model according to Shan and Chen has to be extended for high density ratios as needed for water
and air, validated and applied.
The task includes extending the code in the waLBerla software framework developed
at our chair and occurs in close cooperation with the waLBerla team.
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Essential skills:
- Basic knowledge in Computational Fluid Dynamics
- Programming skills in C++
- Basic knowledge in numerics
Type:
Master Thesis or Diploma Thesis
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