Numerical simulation on combustion characteristics of methane/hydrogen blended fuel for non-premixed conical bluff body burner

Abstract

Blending hydrogen into methane impacts flame stability, morphology, and pollutant emissions. This study, set against the backdrop of hydrogen-enriched natural gas combustion technology, employs a non-premixed coaxial burner with conical bluff body to create recirculation zones for flame stabilization. Combining EDC and GRI-Mech 3.0, the research fills in the gap of effects of hydrogen blending ratio (0–100%) and equivalence ratio vary (0.4–1.4) within a wide range. Keeping equivalence ratio and fuel volume flow rate as constants, as increasing hydrogen blending ratio, the mean velocity in the chamber decreases, the size of vortex structure located in outer recirculation zones reduces, and the flame length is shortened, illustrating the reaction zone shifts to chamber inlet. Furthermore, when Ф = 1.4, average temperature and temperature uniformity are averagely larger 59.82% and 4.21% than that under Ф = 0.4. The CO2 emission at XH2 = 80% is 54.70% averagely lower than that at XH2 = 0%, but peak concentration of NO increases.