4 research outputs found
Assessment of flamelet manifolds for turbulent flame-wall interactions in Large-Eddy Simulations
A turbulent side-wall quenching (SWQ) flame in a fully developed channel flow
is studied using Large-Eddy Simulation (LES) with a tabulated chemistry
approach. Three different flamelet manifolds with increasing levels of
complexity are applied: the Flamelet-Generated Manifold (FGM) considering
varying enthalpy levels, the Quenching Flamelet-Generated Manifold (QFM), and
the recently proposed Quenching Flamelet-Generated Manifold with Exhaust Gas
Recirculation (QFM-EGR), with the purpose being to assess their capability to
predict turbulent flame-wall interactions (FWIs), which are highly relevant to
numerical simulations of real devices such as gas turbines and internal
combustion engines.
The accuracy of the three manifolds is evaluated and compared a posteriori,
using the data from a previously published flame-resolved simulation with
detailed chemistry for reference. For LES with the FGM, the main
characteristics such as the mean flow field, temperature, and major species can
be captured well, while notable deviations from the reference results are
observed for the near-wall region, especially for pollutant species such as
\ce{CO}. In accordance with the findings from laminar FWI, improvement is also
observed in the simulation with QFM under turbulent flow conditions. Although
LES with the QFM-EGR shows a similar performance in the prediction of mean
quantities as LES with QFM, it presents significantly better agreement with the
reference data regarding instantaneous thermo-chemical states near the
quenching point. This indicates the necessity to take into account the mixing
effects in the flamelet manifold to correctly capture the flame-vortex
interaction near the flame tip in turbulent configurations. Based on the
findings from this study, suitable flamelet manifolds can be chosen depending
on the aspects of interest in practical applications