Design Optimization of a Honeycomb Bluff Body for Hydrogen Micromix Combustion

To achieve zero carbon and low nitrogen oxide emissions in aeroengines, this paper proposes a honeycomb bluff body with micromix scheme that is adaptable to hydrogen combustion characteristics. The combustion principles of the proposed micromix element are analyzed, and a parameter-driven micro-mixing chamber design process is established. By combining simulations using Workbench and UG, genetic algorithms and approximate models are employed to obtain the solution with the lowest NOx emissions. The numerical simulations utilize the k-ω SST turbulence model and the diffusion flame method from FGM to analyze the flow field, temperature field, and NO_x emissions of both the micro-mixing single element and a 3 × 3 array. The results demonstrate that the three-dimensional wake vortex coupling of the bluff bodies in the micromix element significantly enhances the turbulence disturbance and mixing of hydrogen and air. Under the inlet conditions of 2030 kPa and 818 K, the optimum single element achieves NO_x emissions below 5 ppm @ 15% O₂.