Hydrogen staging effects on flame stability and emissions in a fuel-flexible combustor

This study investigates the impact of fuel split between Jet-A1 and H 2 in a novel low-swirl combustor designed for low NO x emissions and flashback resistance. The combustor combines airblast atomization for Jet-A1 with H 2 injection in a jet-in-crossflow configuration. Full and staged-injection strategies were examined experimentally at atmospheric pressure and elevated air inlet temperatures. The flame remained predominantly lifted up to 100% H 2 in full injection. Fuel staging enhances stability, extending the pure- H 2 lean blowout limit by a factor of 2.0 at 673 K and 1.6 at 473 K (air inlet temperature) compared with full-injection operation. NO x emissions remain below 15 ppm, with full injection advantageous at full-load and staged injection at part-load. CO emissions decrease substantially even with a modest 15% H 2 . Non-reactive simulations complement the experiments, providing insight into flow and mixing fields for both injection strategies. These findings demonstrate that full and staged injection jointly enable low NO x emission and improved stability limits.