NoX And No2 Emission Of Swirl-Stabilized Nonpremixed Flames Of A H2 - Ch4 Mixture

NOx emission levels and the NO2/NOx ratios were studied in swirl-stabilized H2 - CH4 flames and comparison was made with H2 flames under similar conditions (i.e. system parameters such as Reynolds and swirl numbers, and the recirculation zone residence time). Changing the fuel composition from 100% H2 to 50% H2 - CH4 was found to have moderate effects on the NOx emission level. The NO2/NOx ratios with CH4 substitution can be significantly higher than pure H2 flames (about 80-95% for H2 - CH4 flames, compared to 35-60% for H2 flames), partly explaining its high values in practical gas turbine combustors