An experimental study of the effect of 2.5% methane addition on self-ignition and flame propagation during high-pressure hydrogen release through a tube. (24th January 2020)

• Record Type: Journal Article
• Authors: Zeng, Qian; Duan, Qiangling; Li, Ping; Zhu, Hongya; Sun, Dongxu; Sun, Jinhua
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 4(2020)
• Page Start: 3381
• Page End: 3390
• Publication Date: 2020-01-24
• Subjects: High-pressure hydrogen -- Self-ignition -- Methane -- Shock waves -- Visualization; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.11.155
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: This paper demonstrates experimental investigation on the self-ignition and subsequent flame propagation of high-pressure hydrogen-methane mixture release via a tube. The proportion of methane added to hydrogen is 2.5% (vol.). A transparent rectangular tube (d = 15 mm, L = 400 mm) is used in the experiments. It is shown that the minimum burst pressure required for self-ignition increases 1.57 times for only 2.5% methane addition from 2.89 MPa (pure hydrogen) up to 4.68 MPa (2.5% CH4 addition). This is mainly caused by the following reasons: on the one hand, methane addition can result in the decease of shock intensity inside the tube, thereby lowering the temperature of the combustible mixture; on the other hand, the hydrogen-methane mixture has the higher minimum ignition energy than that of pure hydrogen. Besides, 2.5% methane addition can increase the initial ignition time, weaken the flame intensity and reduce the flame propagation velocity relative to tube wall inside the tube. Moreover, for cases with 2.5% methane addition, the complete flame throughout the tube is formed closer to the back end of the tube. When the self-sustained flame exits from the tube, the maximum overpressure in a confined space increases with 2.5% methane addition. Highlights: The effect of 2.5% methane addition to hydrogen is experimentally investigated. The shock wave intensity is reduced in the presence of the methane. The addition of methane can decrease the possibility of hydrogen self-ignition. Initial ignition occurs in the tube wall and then develops into a complete flame. The hydrogen-methane mixture brings greater combustion overpressure in chamber.