Numerical Investigation of Microjet Assisted Diluents Usage on Effect of NOX Emissons in Turbulent Methane Flame

Combustion and emission characteristics of microjet assisted methane flame have been investigated numerically in the present study. Diluents have been supplied as microjet from the center of the methane flame and therefore, their effects on NOX emissions have been investigated in methane flame. CO2, N-2 and steam have been supplied into the flame zone as diluents for different Reynolds (Re) numbers. A computational fluid dynamics (CFD) code (Ansys Fluent) has been used and modellings have been performed by it in the present study. The PDF/Mixture Fraction combustion model and P-1 Radiation model have been used. Different turbulence models have also been used in combustion modellings andthe best turbulence model has been determined. After combustion modellings have been carried out, NOX predictions have been taken place with NOX post processor in this CFD code based on thermal and prompt NOX mechanisms and the effects of the diluents have been investigated numerically. According to the results, It has been seen that center-fed diluents have contributed suppression of NOX emissions forming in the methane flame. When the diluents are evaluated each other, it has been determined that steam enables more reduction of NOX emissions forming in the methane flame in comparison to CO2 and N-2. This reduction has been provided from 45 ppm to 30 ppm. It can be concluded from the present study that supplying diluents as microjet has also contributed reduction of NOX emissions as well as it affects flame stabilization.