Numerical Investigation of Turbulent Hydrogen-Methane-Nitrogen Non-Premixed Jet Flame

Abstract

In this work, the numerical investigation of the two-dimensional axisymmetric turbulent diffusion flame of a composite fuel was performed by using a computational fluid dynamics code to predict flame structure. The composite fuel was an H₂/CH₄/N₂ gas mixture. The amount of H₂ and N₂ in the fuel mixture varies under constant volumetric fuel flow rate. Fluent, which solves the governing and reaction equations using the finite volume method, was used as the computational fluid dynamics program. The non-premixed model was used for computation of the combustion. The standard k-ε model was used for modeling the turbulent flow. The interaction of the chemistry and turbulence was accounted for by the program with the probability density function model. This model was validated against the experimental data taken from literature. In general, the numerical results of the temperature, velocity, and CO₂ concentration distributions were in satisfactory agreement with the experimental results. The numerical results showed that adding H₂ to the fuel mixture decreases the flame length and generally increases the maximum temperature of the flame. On the other hand, adding N₂ to the mixture decreases both the flame length and maximum flame temperature. The flame length corresponds to the axial position of the peak flame temperature.

Keywords: Combustion Modeling; Composite Fuels; Diffusion Flame; H₂/CH₄/N₂ Flame; Flame Length; Emissions