Modeling and numerical simulation of premixed combustion using the k−ɛ turbulence model

Combustion is a chemical process through which the chemical energy is converted into heat via exothermic reactions. Understanding and optimizing combustion phenomena is crucial for efficient energy conversion across a wide range of engineering applications. In recent decades, CFD has emerged as a powerful tool for the numerical analysis of combustion processes. This paper presents two-dimensional CFD simulations of methane and air combustion in turbulent regime for a free and lean fuel flame in an experimental combustor described and studied in specialized literature. Mathematical model comprises equations of continuity, conservation of species, energy, momentum, and 2 equations corresponding to the standard k − ɛ turbulence model. Production of NO x pollutants was simulated in post-processing computations using the extended Zeldovich mechanism. Results include profiles of temperature, species concentration, turbulent parameters and reaction rates for 3 different combustor heights and 3 different kinetics of 1 and 2 steps. Numerical results have been validated with experimental data available in the literature, obtaining behaviors for the Finite-rate/Eddy-dissipation model that are consistent with other works present in literature. It was determined that, if the Eddy Dissipation Concept model is considered, then the concentration profiles of the main combustion compounds and temperature are generally closer to the experimental profiles; on the other hand, the Finite Rate/Eddy Dissipation model was the most suitable for the concentration profiles of the CO pollutant. This research is useful to evaluate and validate a turbulence model for lean premix combustion based on experimental data available in the literature, and could be used to evaluate combustion performance at new relevant operational conditions, and in the design of new more efficient and less polluting combustors.