Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
COMPARISON BETWEEN MIXTURE FRACTION AND SPECIES TRANSPORT COMBUSTION APPROACHES THROUGH RADIATIVE TRANSFER ANALYSIS IN TURBULENT FLAMES
Submission Author:
Amanda Gonçalves de Figueiredo , RS
Co-Authors:
Amanda Gonçalves de Figueiredo, Francis França, Fernando Pereira
Presenter: Amanda Gonçalves de Figueiredo
doi://10.26678/ABCM.COBEM2021.COB2021-0438
Abstract
Thermal radiation is most often the most important heat transfer mechanism in combustion processes due to the formation of participating gases at high temperatures. Its computational analysis requires modeling the fluid flow, the turbulence, the chemical kinetics and, finally, the combined heat transfer. The simulation of a turbulent methane-air flame was carried out using the CFD (Computational Fluid Dynamics) Software Ansys Fluent, with the choice of methodologies that lead to satisfactory accuracy, as established in the literature, but with changes in the combustion models and, consequently, in the chemical kinetics, in order to evaluate the sensitivity of the problem with respect to ratio of formation of the participating chemical species. The combustion was solved with three different mechanisms: the Non-Premixed Combustion - Steady Laminar Diffusion Flamelet (SLDF) model with detailed reaction mechanism; with the Non-Premixed Combustion - Chemical Equilibrium (CE); and finally with the Species Transport - Eddy Dissipation (ED) models, based on simpler mechanisms of reactions. The turbulence was modeled through the k-ε standard model. For the radiation calculation, the weighted-sum-of-gray-gases (WSGG) was implemented as the spectral model and the discrete ordinates method (DOM) as the spatial-directional model. This study considered the correlation between the absorption coefficient and the temperature and the temperature self-correlation to account for the effects of turbulence-radiation interaction (TRI). As preliminary results, the SLDF model, with greater detail of the chemical kinetics, showed better comparisons with experimental data than the others two models, for which there was a shift in temperature, species concentration and radiative heat flux curves.
Keywords
Mixture fraction, SLDF, eddy dissipation, WSGG, Turbulence-radiation interaction, CFD.
