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Fluids

At what temperature are unburnt mixture properties calculated in the non-adiabatic premixed model?

    • jstrafac
      Subscriber

      The Zimont turbulent flame speed closure requires unburnt mixture properties such as the unburnt thermal diffusivity. In the non-adiabatic model, the unburnt mixture temperature/density is not constant and I can't seem to find a reference showing what temperature/density is used to calculate these quantities. The partially-premixed model uses mixture fraction polynomials and the adiabatic premixed model defines these values explicitly. I don't see anything regarding the non-adiabatic premixed combustion model. It appears to be using a single constant temperature, but I am unable to confirm this.

    • wcao
      Ansys Employee
      Hello The answer to your question depends on if you have checked the "Non-Adiabatic Laminar Flame Speed" option in the "Properties" tab. If yes, the properties will be calculated with the PDF calculator automatically and tabulated as a function of f and radiation loss. While if not checked, it will use the adiabatic properties directly. Thank you.
    • jstrafac
      Subscriber
      Thanks for the response, wcao! I was specifically referring to the non-adiabatic premixed combustion mechanism. Just to confirm, the non-adiabatic premixed combustion mechanism uses the same PDF calculations as the partially-premixed combustion mechanism? This would make sense based on what I see in the data. Neglecting radiation, the mixture fraction of the premixed combustion mechanism is constant and, anecdotally, the unburnt properties appear to be constant throughout the model as well. I appreciate the assist.
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