Application of the Computational Singular Perturbation Method to a Turbulent Diffusion CH₄/H₂/N₂ Flame Using OpenFOAM

This work highlights the ability of the computational singular perturbation (CSP) method to calculate the significant indices of the modes on evolution of species and the degree of participation of reactions. The exploitation of these indices allows us to deduce the reduced models of detailed mechanisms having the same physicochemical properties. The mechanism used is 16 species and 41 reversible reactions. A reduction of these 41 reactions to 22 reactions is made. A constant pressure application of the detailed and reduced mechanism is made in OpenFOAM free and open source code. Following the Reynolds-averaged Navier–Stokes simulation scheme, standard k–ε and partial stirred reactor are used as turbulence and combustion models, respectively. To validate the reduced mechanism, comparison of numerical results (temperature and mass fractions of the species) was done between the detailed mechanism and the simplified model. This was done using the DVODE integrator in perfectly stirred reactor. After simulation in the computational fluid code dynamic (CFD) OpenFOAM, other comparisons were made. These comparisons were between the experimental data of a turbulent nonpremixed diffusion flame of type “DLR-A flame,” the reduced mechanism, and the detailed mechanism. The calculation time using the simplified model is considerably reduced compared to that using the detailed mechanism. An excellent agreement has been observed between these two mechanisms, indicating that the reduced mechanism can reproduce very well the same result as the detailed mechanism. The accordance with experimental results is also good.