  A recently proposed rotational flamelet model is developed and tested in an
improved framework of detailed chemistry and transport models. The rotational
flamelet model, in contrast to standard two-dimensional or axisymmetric
irrotational models, incorporates the effects of shear strain and vorticity on
local flame behavior and is three-dimensional by nature. A similarity solution
is used to reduce the three-dimensional governing equations to a set of ODEs
involving a transformation to a non-Newtonian reference frame. Multiple
flamelet cases including both diffusion and premixed flames are tested to
demonstrate the impact of vorticity on flame structure, extinction, and local
mixture composition. For diluted hydrogen flames where the location of minimum
density coincides with the location of peak temperature, the centrifugal force
induced by vorticity reduces mass flow rate in the flame zone, effectively
lowering the local strain rate. This results in increased residence time, thus
extending flammability limits and reducing burning rates. For
pure-hydrogen/oxygen flames where minimum density lies between the flame zone
and the fuel inlet boundary, centrifugal forces do not significantly modify
flame behavior. Stable and unstable branches of extinction curves (S-curves)
are computed which showcase how vorticity extends flammability limits. These
capabilities of the rotational flamelet model reveal that vital physics are
currently missing from two-dimensional, irrotational, constant-density,
constant normal strain rate flamelet models. The improvements noted regarding
detailed chemical kinetics, transport formulation, and thermo-physical
properties bring the new flamelet model to par in these areas with existing
models, while surpassing existing models in terms of physical emulation.
