Understanding soot production in a Jet A-1 laminar coflow non-premixed flame

Abstract

The understanding of soot formation in a non-premixed laminar co-flow flame fueled by vaporized Jet A-1 is aimed to be improved through this combined experimental and numerical study. Non-intrusive LED-based multi-wavelength line-of-sight attenuation and emission techniques are used in experimental measurements, generating two-dimensional fields of soot volume fraction and temperature. The methodology also allows to calculate the soot absorption function, which is used to evaluate soot volume fraction. Numerical simulations are carried out using the hybrid chemistry (HyChem) reaction model. To better account for jet fuel pyrolysis, oxidation, and soot production, the POSF10264 kinetic model is expanded to include polycyclic aromatic hydrocarbons (PAH) with up to five rings. This modification is validated through zero- and one-dimensional models in Cantera. Simulations of sooting co-flow non-premixed flames are conducted using the CoFlame code, in which reversible nucleation and PAH adsorption models are employed. A close match is observed between simulations and experimental data of temperature and soot volume fraction, specially along the flame wings. On the other hand, soot volume fraction is underpredicted by a factor of 3 near the centerline, indicating that improvements must be sought on the PAH condensation sub-model for particles dynamics or on the prediction of PAHs species.