Lower flammability limit of hydrogen/air mixture under different electrode parameters, initial pressure and diluent gas

• Published in: International journal of hydrogen energy 2023-06, Vol.48 (54), p.20815-20826
• Main Authors: Li, Xiaolin, Bi, Mingshu, Zhang, Kai, Zhang, Zongling, Gao, Wei
• Format: Article
• Language: English
• Subjects: Electrode parameters; Hydrogen; Inert gas; Initial pressure; Lower flammability limit
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2023.03.058

The investigation of the lower flammability limit (LFL) is essential to the security application of hydrogen. In the present work, the LFL of hydrogen under a variety of conditions is systematically measured. The effect of electrode gap length (2–4 mm), electrode shape (30°, 90°, and spherical) and initial pressure (40–200 kPa) on the LFL of hydrogen/air mixture are analyzed. It shows that the LFL of hydrogen/air mixture increases with the increase of initial pressure and decreases with the increase of electrode gap length. The LFL of 30° electrodes is higher than that of 90° and spherical electrodes at the initial pressure higher than 80 kPa. Besides, the LFL of hydrogen/air mixture diluted with inert gas (CO2 and N2) at different initial pressure (50 kPa, 100 kPa, and 150 kPa) is investigated. The LFL of H2/air/CO2 mixture increases with increasing CO2 concentration, while the LFL of H2/air/N2 mixture is almost unchanged under different N2 concentration. •The LFL of hydrogen under a variety of operating conditions is systematically measured.•The effect of electrode parameters, initial pressure and diluent gas on the LFL of hydrogen/air mixture are analyzed.•The flame propagation characteristic under the LFL of hydrogen is investigated.