16.10.2 Two-Mixture-Fraction Approach

When a secondary stream is included, ANSYS FLUENT will solve transport equations for the mean secondary partial fraction ( $p_{\rm sec}$) and its variance in addition to the mean fuel mixture fraction and its variance. ANSYS FLUENT will then look up the instantaneous values for temperature, density, and individual chemical species in the look-up tables, compute the PDFs for the fuel and secondary streams, and calculate the mean values for temperature, density, and species.

Note that in order to avoid both inaccuracies and unnecessarily slow calculation times, it is important for you to view your temperature and species tables in ANSYS FLUENT to ensure that they are adequately but not excessively resolved.