Numerical Simulation of Turbulent Nonpremixed Methane Flames of Swirling Burners

The swirling turbulent non-premixed methane flame, was numerically simulated with the Renormalization Group (RNG) k~ε model of the Fluent software. The predicted distribution of temperature, concentrations of species, as well as the recirculation zone all agree well with experimental data got from the Sandia National Lab. , USA, which further verify the RNG model's reliability. The influence of the different swirl numbers on the shape of flame, concentrations of species and emission of NO was also investigated. It is found that, the temperature is low in the center of outlet of the swirling burner and tend to high at downstream locations, while the concentrations of CO₂, CO, H₂O and H₂ follow a similar distribution to the temperature profiles. Increasing the swirl number increases the turbulent mixing rates in the primary recirculation zone, but leads to higher levels of NO.