Development of an Additive Manufactured Novel Hydrogen Combustor on Basis of the Proven Micromix Principle

Abstract To support the transition toward climate-neutral aviation, hydrogen is considered one of the most promising energy carrier candidates. However, hydrogen combustion is inherently prone to high NOx emissions. To address this challenge, the micromix principle has been developed to enable low-NOx, flashback-safe hydrogen combustion in gas turbines. Building upon this principle, this paper presents the development, design methodology, and evaluation of a novel, additively manufactured micromix combustor configuration — the Radial-Spokes (RS)-Burner. Unlike the established Ring-Burner, which distributes hydrogen circumferentially, the RS-Burner employs radial hydrogen distribution through multiple spokes. This new arrangement requires a complete reorientation of the micromix principle. The design is enabled through additive manufacturing (AM) using laser powder bed fusion (LPBF). A structured design methodology is introduced, accounting for design challenges like varying spoke width and injector hole diameters. Numerical simulations were conducted using Star-CCM+ to analyze the combustion performance of the RS-Burner across a range of operating conditions compared to the Ring-Burner. Additionally, results were validated against experimental data using test burner and real engine test data. The results confirm the viability of the RS-Burner as a low-NOx hydrogen combustion chamber. The new concept shows stable combustion, satisfactory flame separation, and high combustion efficiency. NOx emissions were significantly reduced at part-load conditions compared to the reference design. The presented study highlights the feasibility and advantages of combining micromix combustion with additive manufacturing to meet the emission targets of future hydrogen-powered gas turbines.