Surface Roughness Effects on the Operability and Performance of a Hydrogen Jet Burner

Abstract Over the past decade, Additive Manufacturing (AM) has gained considerable traction in the gas turbine industry. Manufacturers now look to AM for the production of critical components central to the combustor architecture. However, AM struggles to achieve satisfactory surface finishes, with its increased surface roughness shown to impact axial velocities, heat release, NOx emissions, and stability limits. Correlations between increased roughness and boundary layer flashback resistance are of significant interest for lean premixed combustion of high hydrogen content (HHC) fuels. With the development of innovative burner configurations designed to address static stability issues in HHC fuels, and the growing use of AM in their fabrication, studying roughness effects on these designs is essential. This study aims to quantify the impact of surface roughness on an industry-relevant jet burner configuration, building on previous research by the authors using premixed swirl geometries. A premixed jet burner was developed with an interchangeable section to accommodate varying surface textures. The burner was characterized under atmospheric hydrogen-fired conditions at thermal powers ranging from 10 to 25 kW. Both smooth and rough inserts representing traditional machining and selective laser melting manufacturing techniques were utilized. The findings highlight how surface roughness influences flame topology, static stability, and emissions, providing an experimental basis for future numerical studies on roughness sensitivity in advanced burner designs.