Must EDC model need an initial flow field?

[fanbo9802]

I am wondering if I want to use EDC model to simulate combustion with a chemical mechanism, should I obtain an initial field using ED or other simpler methods? And should the results include a temperature result or just a cold flow field result?

[Ren]

Either approach should work. You can use a computationally more efficeint model such as the EDM to first obtain a reasonably converged combustion solution and then switch to the EDC calculation, or obtain a non-reacting flow solution to first establish the flow field and the main species (fuel and oxidizer speces) field, then start he full EDC combusiton calculation. In the second approach, you need to numerically "ignite" the mixtrure by patching.

[fanbo9802]

Does the FR/ED approach support the multiple reactions? I want to simulate spray combustion through EDC, and I want to use a more efficient model to simulate an initial field with a reduced mechanism that contains 20 species and 39 reactions.  Is it reliable to import the mechanism with the FR/ED model?

[Ren]

I would not recommend using the FR/ED and a detailed mechanism for the initial solution calculation. You have many options:

ED with a 1-step or 2-step global scheme, or

Non-premixed model, or

ED with Relax to chemical equilirium

The precursor calculation and the EDC calculation do not need to use the same mixture material.

[mollyfloppy]

The subject of selecting a starting field when utilizing the Eddy Dissipation Concept (EDC) model to simulate combustion with full chemical pathways is a highly practical one in CFD. In reality, there is no single "right way," but the option is determined by the problem's complexity and processing resources. In practice, FR/ED is not intended to represent combustion kinetics in the same detail as EDC.