January 30, 2025, 23:59
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Why is Ammonia Combustion Not Occurring with the WALE Model in OpenFOAM (2D Wedge Geo
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#1
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New Member
Jehan Sharook Rassdeen
Join Date: Sep 2024
Posts: 12
Rep Power: 2
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Hi everyone,
I’m working on a 2D wedge-type ammonia (NH₃) combustion simulation in OpenFOAM using the WALE (Wall-Adapting Local Eddy-viscosity) model for LES. However, I’m facing an issue where combustion is not occurring—temperature isn’t increasing, and there’s no sign of ignition or reaction. Interestingly, when I switch to other turbulence models (e.g., k-ε or k-ω,LES dynamicKeqn,Keqn,..), combustion works as expected.
Here’s a brief overview of my setup:
- Solver: reactingFoam
- Combustion Model: PaSr(Eddy Dissipation Concept)
- Chemistry: A detailed ammonia mechanism (e.g., Hans.)
- Geometry: 2D wedge (axisymmetric)
- Boundary Conditions: Properly defined for temperature, pressure, and species concentrations (within flammable limits)
- Grid Resolution: Fine enough to resolve the flame front
What I’ve Tried:
- Verified the chemistry mechanism and reaction rates.
- Checked initial and boundary conditions to ensure they are within the flammable range for ammonia.
- Refined the grid to ensure proper resolution of turbulent eddies and flame structures.
- Tested other turbulence models which successfully predict combustion.
My Questions:
- Why might the WALE model fail to predict combustion in this case, while other turbulence models work?
- Are there specific settings or adjustments needed for the WALE model to handle ammonia combustion?
- Could the issue be related to the subgrid-scale combustion model (PaSr) or the coupling between turbulence and chemistry?
- Has anyone successfully simulated ammonia combustion using the WALE model in OpenFOAM? If so, what were the key settings or considerations?
Any insights, suggestions, or references would be greatly appreciated!
Thanks in advance!
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