Numerical investigation of combustion performance and pollutant emissions of methane/hydrogen fuel mixture in micromix combustor

Recent research has increasingly focused on the stable combustion of H2-enriched fuels to reduce carbon and thermal NOx emissions, with the aim of reducing the adverse effects of greenhouse gases on the environment. This study introduces a micromix combustor with 40 round nozzles that facilitate the crossflow of fuel to air to achieve stable combustion and prevent flashback. The combustor performance and emission characteristics were assessed at an operational power of 0.1 MW. An experimental setup was developed to explore and validate the numerical methods. The H2 enrichment and equivalence ratio (ER) significantly affected the combustion performance and thermal emissions. High temperatures were computed across all ERs of the fuel mixture, leading to a significant increase of 74.1 % in the pattern factor. Moreover, the combustion efficiency of the fuel mixture was increased by both the addition of H2 and variation in the ER. The highest combustion efficiency (88.6 %) was observed at an ER of 0.6. Pollutant emissions increased as the ER increased to 0.8 and decreased as it increased further. Thus, the addition of H2 and reduction of the ER can significantly reduce the CO, CO2, and thermal NOx emissions by reducing and increasing the carbon and OH concentrations, respectively.