Objective Hydrogen-enriched natural gas (HENG) delivered via pipeline transmission potentially induces blame liftingand flashback during combustion, adversely impacting flame stability at terminal gas equipment. This study aims to investigate theinfluence of various air coefficients and hydrogen blending ratios on the burning flame stability of typical terminal gas equipment throughsimulation and experimental verification.

Methods Focusing on a 10 mm circular single burner port within terminal gas equipment, thesimulation calculations were performed respectively under the blame lifting conditions with primary air coefficients of 0.40, 0.60, 0.65, 0.70, and 0.80, alongside hydrogen blending ratios of 0, 3%, 5%, and 10%, and the flashback conditions with primary air coefficients of0.60, 0.65, 0.70, and 0.80, combined with hydrogen blending ratios of 0, 3%, 5%, and 10%. Subsequent experimental verification wasconducted adhering to an experiment plan designed for testing the flame stability of natural gas (pure methane) doped with hydrogen, in alignment with GB/T 16411-2023, titled "Universal test methods of gas burning appliances for domestic use".

Results The averagerelative error between the simulated and measured values of the critical gas flow rate at the port stood at 5.73% under the blame liftingscenario, which verified the reliability of the blame lifting simulation model. Conversely, this relative error rose to 11.22% under theflashback scenario, attributed to the influence of the experimental conditions. As the hydrogen blending ratio increased, a corresponding elevation in the blame lifting limit was noted, leading to a reduced probability of blame lifting. Consequently, hydrogen blending wasrecognized as advantageous for deterring blame lifting occurrences. Furthermore, with an increase in the hydrogen blending ratio, asimilar rise was observed in the flashback limit, signifying an elevated tendency of flashback.

Conclusion The study findings offer a reference for the industrial applications of hydrogen-enriched natural gas. Simulation serves as a targeted analytical method to assessthe adaptability of hydrogen blending for end users of natural gas under restricted experimental conditions. Furthermore, in application scenarios involving a high hydrogen blending ratio, it is advisable to conduct tailored tests to guarantee the stable performance of terminalgas equipment.