Impact of Oxygen Enrichment and CO2–H2O Dilution on Stability and Pollutant Emissions of Non-Premixed Swirling Turbulent Flames

The aim of this work is to investigate the effect exhaust gas recirculation (EGR: water vapor and CO2), with without O2 enrichment, on non-premixed turbulent flames stabilized a swirl burner. motivation includes CO2 capture applications using CO2, combustion biogas that containing use EGR or H2O in certain industrial reduce pollutant emissions. Experiments were carried out coaxial burner placed chamber 25 kW nominal power. oxidant (air-O2, + H2O, CO2) introduced annular part though swirler. fuel (CH4) fed central tube injected radially at exit section. study focuses laminar burning velocity, emissions, flame stability, flow fields measurements different fractions O2, mixture. fraction diluents varied from 0 20%, concentration 21 25% (in vol.) number 0.8 1.4. Different are recorded: OH* chemiluminescence locate front, Stereo-PIV analyze field, emissions analysis (NOx CO) temperatures chamber. Results show dilution significantly influences characteristics. Dilution increases lift-off height reduces stability especially high (16–20%), whereas enrichment decreases enhances stability. increase NOx CO reveals coherent structure swirling as well corresponding axial tangential velocities. underlying velocity determined by 1D calculation COSILAB GRI3.0 mechanism.