Simulation of soot nanoparticles formation and oxidation in a turbulent non-premixed methane-air flame at elevated pressure

In this work, a hybrid finite element volume FEV method is further extended to simulate soot nanoparticles formation and oxidation in a heavily sooting co-flow methane diffusion flame at elevated pressure. In this regard, two-equation soot model is used and soot oxidation due to O₂ is further taken into account. Considering full soot oxidation and respecting the physics of the flow, physical upwinding influence scheme PIS for approximation of soot mass fraction fluxes over cell faces is further extended. To describe soot nucleation process, phenyl-route, based on soot inception from polycyclic aromatic hydrocarbons PAHs, is used and a further kinetics scheme, which consists of 80 chemical species and 1416 chemical reactions, is employed. The flamelet combustion model, Two-equation standard k - ε turbulence model and suitable wall functions are applied. Using probability density functions PDFs, turbulence-chemistry interaction is taken into account. Radiation effects of both gases and soot are taken into account assuming optically thin limit. Using bi-implicit approach, the governing equations are solved thorough two different sequential matrices. Comparing with the measured data, the current solution successfully predicts the essential characteristics of flame and soot nanoparticles.