Combustion CFD — Reacting Flows, Flames & Species Transport
Premixed and diffusion flames, species transport equations, combustion chemistry, flamelet models, NOx prediction, and turbulence-chemistry interaction.
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Quick Explainer
How does chemistry interact with turbulence in combustion simulation?
Chemistry happens on nanosecond timescales, turbulence on millisecond timescales. Direct simulation of all chemistry is impossibly expensive. Flamelet models tabulate chemistry solutions as a function of mixture fraction and progress variable, then look them up during the CFD solve — fast and accurate for many industrial flames.
What is the difference between premixed and diffusion flame models?
In premixed flames, fuel and oxidizer mix before combustion — like a gas engine or Bunsen burner. The flame propagates at a burning velocity. In diffusion (non-premixed) flames, fuel and oxidizer meet at the combustion zone — like a candle. Reaction rate is limited by mixing, not chemistry. Gas turbines and diesel engines use diffusion or partially premixed flame models.