In studies of a turbulent flow with mixing-sensitive chemical reactions, the
equations for the PDF of scalars (temperature and mixture component concentrations) are
applied in combination with the conventional turbulence models that contain the equations for
statistical moments. The PDF method advantage is an accurate representation of the
chemistry influence in model equations. However, to calculate correlations responsible for an
averaged chemical reaction rate, one needs a more thorough description of micromixing. As
micromixing is governed by the small-scale flow structure, the latter can be considered
statistically homogeneous. So, the well-developed homogeneous turbulence theory is used for
closing the micromixing models. Just the adequate description of micromixing connected not
only with the successful modeling of the chemistry influence, but first with a reasonable
analysis of the entire mixing process, remains a stumbling block for the PDF method. This
problem has received particular attention in the present work where the problem on mixing
with chemical reacting in the homogeneous turbulent flow is stated by means of both the
method of statistical moments for turbulence parameters and the mixture fraction PDF
method for closing unknown correlations responsible for chemical reacting. Several known
micromixing models (LSME/IEM, Langevin, multi-zone PDF) applicable in the PDF transfer
equation are compared to explain their influence on an averaged reaction rate to be calculated.
Keywords: Turbulent flow, mixing-sensitive chemical reaction, micromixing,
statistical moment, probability density function, reynolds number, damköhler
number, mixture fraction, progress variable.
