A post processing technique to predict primary particle size of sooting flames based on a chemical discrete sectional model: Application to diluted coflow flames

A forward approach for the validation of soot sizing models using laser-induced incandescence (LII)

“…However, the lower detection limit may depend on the sensitivity of the system, as it was pointed out by Sirignano et al [63]. Even if the value of d det,min only slightly affects the soot volume fraction determination since the contribution of small particles is negligible [33], it can generally affect the value of d pp calculated from the numerical PPSD [26]. Unfortunately, d det,min is not available for all experiments, potentially affecting the accuracy of the inverse validation method.…”

“…Therefore, the generally used approach, i.e., assuming air properties when retrieving the PPSD from the measured LII signal [10,20,31], is inaccurate. As an example, the M g value has been extracted from the numerical simulations of different sooting flames at atmospheric pressure [26]. For a premixed ethylene laminar flame with an equivalence ratio of 2.1 and co-flow ethylene laminar flames with various ethylene content in the fuel stream (32%, 40%, 60% and 80 % volumetric ratio), the M g value can vary between 25kg/mol and 30 kg/kmol in the sooty region; whereas, the general assumption is M g = 28 kg/kmol.…”

“…In the following, both the traditional and the synthesized LII signal comparisons are performed for a target flame of the soot research community. The objective here is not the validation of the numerical model used for the simulation since it has been already discussed in [26] but to prove the feasibility of the forward approach. First, the mean diameters are calculated from the numerical PPSD obtained in [26] and compared to measurement results [10,19,20].…”

“…The objective here is not the validation of the numerical model used for the simulation since it has been already discussed in [26] but to prove the feasibility of the forward approach. First, the mean diameters are calculated from the numerical PPSD obtained in [26] and compared to measurement results [10,19,20]. Then, the forward validation procedure is applied by reconstructing the synthesized LII signals from the numerical results at 4 different height above burners (HABs) and by comparing the E LII and ⋆ LII indexes to the experimental data.…”

“…4. The input numerical results are obtained from detailed simulations already validated in [26] and the experimental LII signals are extracted from [10]. Differences between measured and synthesized signals are highlighted and conclusions on the potential of the proposed approach for validating numerical models for the PPSD prediction are finally reported.…”