### 9.2.1. Which Model is the Most Appropriate?

The following table is meant as a guide in helping you choose which combustion model is most suitable for your simulation. You are also encouraged to read the following sections, which describe how to set up each model to obtain the most accurate results.

Eddy Dissipation Model | Turbulent Fast reaction compared to turbulent time scale (high Damköhler number) Reaction rate dominated by turbulent mixing of reactants or fresh and burned gases (premixed)
Finite Rate Chemistry Model | Laminar or turbulent If turbulent, reaction rate slow compared to turbulent time scale (low Damköhler number) Reaction rate dominated by kinetics (chemistry) Kinetic data for reaction rates required May need special initialization for flame ignition (temperature dependence of reaction rates)
Combined EDM/FRC Model | Turbulent Whole range of Damköhler numbers Kinetic data for reaction rates required May need special initialization for flame ignition (temperature dependence of reaction rates).
Laminar Flamelet Model | Fast chemistry (high Damköhler number) Turbulent Non-premixed "Fuel" and "Oxidizer" well defined, Chemistry library required
Burning Velocity Model, BVM (Partially Remixed), (Turbulent Flame Closure) | Turbulent Premixed or partially-premixed "Fuel" and "Oxidizer" can be mixed (specify inlet mixture fraction) Chemistry library required

The Damköhler number is the ratio of flow-time scale to chemical-time scale:

| (9–11)

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