Characterisation of turbulent non-premixed hydrogen-blended flames in a scaled industrial low-swirl burner

The performance of a scaled industrial, non-premixed, low-swirl burner design was experimentally investigated for hydrogen addition to natural gas. Two strategies for introducing hydrogen are considered, namely, conserving (i) heat input and (ii) velocity/volumetric flow of the original fuel. This work characterises the effects on key performance metrics of the burner as hydrogen fraction is increased. Compared with natural gas, the results with hydrogen showed a 33 % reduction in the radiant fraction and up to a 380 % increase in NOx emissions. The lift-off height was reduced by a maximum of 23 % and 51 % for addition of 10 and 30 vol% hydrogen addition, respectively, with 100 % cases becoming completely attached to the burner. The influence of hydrogen-addition strategy and air adjustment was shown to be significant with respect to NOx emissions but less significant than the resulting changes in fuel composition and heat input with respect to flame appearance, stability and radiant heat transfer.