[Jonsy]

Hi!
I always used Star CCM+ for internal combustion engine applications but now, for my post-graduate degree thesis, I switched to fuel cell simulations.
I read many studies about PEMFC modeling but it seems that nobody actually use Star CCM for this kind of applications. So i 'studied' user guide chapters about electrochemistry and surface reaction models but, in one month, i still can not run a decent simulation.

I would like to simulate a discharge with a Cell Voltage of 0.77 V.
The only simulation involving electrochemical surface reactions that seemed to reach convergence is the following:

1. Geometry:
The simplest possible cell, formed by 3 closed parallelepipedons representing: anode (multi-component flowing gas region: H2 + H2O), cathode (multi-component flowing gas region: O2 + H2O) and MEA (Membrane Electrode Assembly solid region)
Mesh.PNG

2. Physics
- Anode and Cathode:
3D, steady, multi-component gas, non reacting, segregated flow and species, gradients, costant density, laminar flow, electrochemistry, electrochemical reactions, electromagnetic, electrodynamic potential.
- MEA:
3D, steady, solid, gradients, electrochemistry, electrochemical reactions, electromagnetics, electrodynamic potential, solid ion.
I'd like to model a Nafion MEA, so i thought to costumize the standard solid material modifying its electrical conductivity according to the proton conductivity of Nafion.

3. Boundary Conditions
- Anode and Cathode:
mass flow inlet, pressure outlet

- Interface Anode/MEA
oxidation surface reaction: 2 H2 -> 4e- + 4H+
Equilibrium Potential: Field function
Specific Exchange Current Density: 1500 A/m^2

- Interface Cathode/MEA
reduction surface reaction: O2 + 4H+ + 4e- -> 2 H2O
Equilibrium Potential: Field function
Specific Exchange Current Density: 1.5 A/m^2

- External Anode Boundary (wall)
Electric Potential: 0 V

- External Cathode Boundary (wall)
Electric Potential: 0.77 V

4. Results
Scalar Velocity.PNG
Scalar Electric Potential.PNG
Scalar Electric Current Density.PNG
Residuals.PNG

I know that this model is far too simple and result values don't mean anything, but i'm trying to understand how it works and what i could improve.

I'll be thankful to anyone could give me some tips and advices!

[floaty]

Hello Jonsy,

the 13.02 tutorial guide has an SOFC tutorial which should represent a good start.

Regards, Christian

[Jonsy]

Originally Posted by floaty

Hello Jonsy,

the 13.02 tutorial guide has an SOFC tutorial which should represent a good start.

Regards, Christian

actually i used 12.02 user guide (according to my software version) but unfortunately it only talks about SOFC but with no details neither tutorials. I’ll check it out the new guide version for sure, so thank you Christian! ����

[Jonsy]

Excuse me can you tell me where to find and to download 13.02 user guide?
i checked on internet but finding that is more difficult than i thought...i don’t have credentials to access to steveportal so can anyone share pdf of it (or just the part about sofc tutorial)?

[Jonsy]

Ok I found it! Thanks again

[cfdominik]

Hi everyone!

I am also trying to set up a PEMFC model with star ccm+ 13.04. to analyze the generation of liquid water at the cathode.
In the "whats new in version 13.02." it says you can use a Mixture Multiphase (MMP) Model to simulate liquid water in the fuel cell.

To do so, I chose the following physics models for the air (cathode side) continuum:
- Electrodynamic Potential
- Electromagnetism
- Electrochemical Reactions
- Electrochemistry
- Laminar
- Gradients
- Multiphase Equation of State
- Multiphase Segregated Flow
- Multiphase Interaction
- Eulerian Multiphase
- Steady
- Three Dimensional

I then started setting up my two phases for the Eulerian Multiphase Model:
Gas Phase (containing nitrogen (N2) and oxygen (O2))
- Multi-Component Gas
- Flow
- Laminar
- Non-reacting
- Segregated Species
- Constant Density
- Segregated Fluid Isothermal


Liquid Phase (Water)
- Liquid
- Flow
- Laminar
- Constant Density
- Segregated Fluid Isothermal

I then want to set up the surface reactions at the proton exchange membrane (PEM) but I can not select any of the defined gases or liquids as reactants or products, more precisely there is no "Reactants" or "Products" folder in the simulation tree, only the "Properties".

However, when you create a physics continuum with just the Multi-Component Gas Model as Material it's no problem to select the defined components as reactants or products.

Could you successfully develop your model, Jonsy?
I am very thankful for any kind of advice!


dominik