Development of a Novel Hydrogen Burner Using Additive Manufacturing

Abstract In the aerospace industry, hydrogen has been embraced as a gas turbine fuel. Hydrogen combustion holds significant promise for enabling zero CO2 emissions. However, the transition from hydrocarbon to hydrogen fuel presents new challenges. Designing hydrogen combustors with low NOx emissions across a wide operability range, spanning flashback to lean blowout, requires intensive work, both numerically and experimentally. In this study, a design for an expandable micromixer-type hydrogen combustor is presented. The core design features square fuel rods, each equipped with four orifices for injecting gaseous hydrogen streams, which are rapidly mixed by crossflow to form microflames. Within each fuel rod, a triply periodic minimal surface structure is designed to serve as both a support material and a heat sink for transferring heat from anchored microflames. To achieve a wide operability range, two sets of fuel rods, namely pilot and main burners, are separately controlled with different fuel splits. To maximize the number of flames while preventing flame interaction, these burners were arranged in a staggered grid pattern, with a 45° offset in their orientation. Large eddy simulation (LES) with finite-rate hydrogen-air chemistry was implemented, and the numerical methods were validated by comparing their results with experimental results. The results of LES with the reduced Mevel mechanism were consistent with the test results. The use of additive manufacturing with Ni-based alloy powder significantly reduced the lead times for variant tests, enabling the rapid development and iteration of burner designs. Single-burner tests were conducted under atmospheric conditions, and each configuration was tested with and without confinement using quartz tubes. The presence of an outer recirculation zone improved the resilience of the burner to lean blowout. The LES exhibited good performance in predicting combustion instability under selected conditions. Future works will consider optimizing burner designs and conducting multiburner test under elevated conditions.