Abstract | The measurement of soot and soot precursors is
important for understanding the formation of soot particles
in flames. In this paper, we use the difference between laserinduced
incandescence (LII) and two-dimensional extinction
measurements to assess the contribution of soot precursors
to the extinction measurement. LII measurements are
performed with a high spatial resolution of 100 μm to determine
the soot volume fraction (fV) in a laminar ethylene/
air non-premixed flame at the standard Gülder conditions.
While LII is specific to mature soot only, the extinction data
represent attenuation due to mature and young soot (absorption
and elastic scattering) and also absorption by soot
precursors. The difference between the two measurements
indicates the contribution of soot precursors and allows
a determination of the maturity of soot. This is important
knowledge for those using extinction techniques to measure
soot concentration, as the contribution from soot precursors
may lead to an overestimation of the mature soot concentration.
Further, regions with high soot-precursor concentrations,
which lead to soot formation, can be identified. |
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