Predicting the soot emission tendency of real fuels – A relative assessment based on an empirical formula

Investigation of the sooting propensity of aviation fuel mixtures

“…To understand the above measured sooting propensity from the molecular structure point of view, we considered employing hydrogen deficiency (HD) as a measure for the presence of unsaturation and cyclic structure present in a molecule. This is to the extension of our earlier study [10] where we showed that the particle emissions measured in a ground-based V2527-A5 engine of an Airbus A320 can be extrapolated to other fuels using their HD and one reference measurement. This assessment was also observed to be extended to the smoke point and sooting tendency measurements from the literature.…”

“…These results show that the hydrogen deficiency is a simple tool to gain information about the sooting propensity of fuels without doing extensive experiments or calculations. Furthermore, it was already shown in our recent publication in Kathrotia and Riedel [10] that though HD is merely the subset of H-content or H/C ratio of hydrocarbon molecule, it provides extrapolation of the known soot emissions. Compared to it, H/C ratio of the fuel can be linearly related to the emission, but this relationship is non-predictive, i.e., cannot be extended to predict soot emissions directly.…”

“…A useful correlation to compare the sooting propensity of any multicomponent fuel arises from the definition of the 'Hydrogen Deficiency' (HD) [10]. Indeed, the hydrogen deficiency does not provide data to quantify the soot emission but is beforehand a measure for the amount of cyclic and unsaturated molecular structures being present in a fuel.…”

“…Though cyclic and especially aromatic (cyclic and unsaturated) components in a jet fuel account for most of the soot formation in contrast to bulk n-, and iso-alkanes, the hydrogen deficiency nevertheless correlates with the sooting propensity of jet fuels. The HD-number poses an easy way to assess the sooting behavior of a jet fuel knowing its molecular composition [10]. Therefore, the experimental results of the sooting propensity will be compared with the predictions according to the hydrogen deficiency correlation.…”

A comparative study of the sooting tendencies of various C5–C8 alkanes, alkenes and cycloalkanes in counterflow diffusion flames

“…Existing soot indices include the critical equivalence ratio (or C/O ratio) where soot starts to appear in premixed flames [27] or in a micro flow reactor (with maximum temperature below 1500 K) [ 28 , 29 ], the smoke point (SP) and threshold soot index (TSI) as determined from the critical flame height at which soot begins to emit from the flame tip in a wick-fed lamp or coflow burner [30] , [31] , [32] , and the yield sooting index (YSI) based on the measurement of peak soot volume fraction in a methane/air coflow diffusion flames by doping small amounts of target fuel [ 33 , 34 ]. Several numerical predictive models pertinent to YSI have also been developed [ 25 , [35] , [36] , [37] , [38] ]. Moreover, Barrientos et al.…”