Analysis of the environmental impact of a swirl burner: hydrogen and natural gas mixture feeding

Advanced combustion approaches in gas turbines suggest the use of alternative fuels to reduce pollutants emissions and to improve performances. Conventional hydrocarbon fuels blended with hydrogen have also been proposed as a cross-over strategy for the hydrogen-energy based infrastructure of the future. The flame structure and flow field modifications induced in a confined lean non-premixed natural gas swirled flame by hydrogen addition were experimentally investigated. Two different typologies of fuel injection were considered: coaxial and transverse with respect to the swirled air stream. With increasing hydrogen content, temperature measurements and visual inspection of the flame pointed out the appearance of a hotter and more reactive zone close to the reactants efflux. Moreover, when H2 is added to natural gas, experimental results showed an unexpected increase in pollutants emissions (both CO and NO x ) and soot formation (only for axial fuel injection)