Experimental investigation on the vented flame and pressure behaviour of hydrogen-air mixtures

IF 3.6 3区 工程技术 Q2 ENGINEERING, CHEMICAL
Yuhuai Sheng , Zhenmin Luo , Litao Liu , Zhe Yang , Fan Meng , Zhe Dong , Yanni Zhang , Jiao Qu , Jun Deng , Tao Wang
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引用次数: 0

Abstract

To explore the changes in pressure and flame propagation inside and outside the vessel when the pipe diameter does not match the vent diameter, and to check the conservatism of standards NFPA 68 and EN 14491 for this case, an experimental apparatus was utilized to investigate the influences of static activation pressure (0.7–1.75 bar) and vent diameter (30–70 mm) on the deflagration behavior of hydrogen–air mixtures (Φ: 0.6–1.4). The vented pressure, flame propagation, and pressure–flame interaction characteristics of hydrogen–air mixtures were observed and analyzed. Additionally, the conservatism of the calculated venting area under the experimental conditions of NPFA 68 and EN 14491 was verified. The results indicated that under an equivalence ratio of 0.6, the pressure-time curve inside the container exhibited only one peak (Pmax11). In the stoichiometric and fuel-rich states, the pressure-time curve inside the container exhibited two peaks attributed to the decrease in venting efficiency due to the secondary explosion inside the pipe, increasing the turbulence intensity within the container. When the static activation pressure is 0.7 bar, the pressures of the three vent diameters of 30, 50 and 70 dropped by 11.34%, 24.38% and 26.86% respectively. And the Pmax11 at Φ = 1.0 and Φ = 1.4 are similar, while this phenomenon is not observed for other vent diameters. When the vent diameter was inconsistent with the duct diameter. the calculations of both standards were conservative. However, under these testing conditions (vent diameter: 30–70 mm, static activation pressure: 0.7–1.75 bar), the NPFA 68 calculations yield a conservatism range of 3.3–11, whereas EN14491 ranges from 1.6 to 15.7. The NPFA 68 results were more stable and concentrated, making these conditions more suitable for industry safety design in hydrogen venting.
氢气-空气混合物通风火焰和压力行为的实验研究
为了探讨当管道直径与通风口直径不一致时容器内外压力和火焰传播的变化,并检验 NFPA 68 和 EN 14491 标准在这种情况下的适用性,我们利用实验装置研究了静态活化压力(0.7-1.75 巴)和通风口直径(30-70 毫米)对氢气-空气混合物(Φ:0.6-1.4)爆燃行为的影响。对氢气-空气混合物的排气压力、火焰传播和压力-火焰相互作用特性进行了观察和分析。此外,还验证了在 NPFA 68 和 EN 14491 实验条件下计算出的排气面积的保守性。结果表明,在等效比为 0.6 的条件下,容器内的压力-时间曲线只表现出一个峰值(Pmax11)。在化学计量状态和燃料丰富状态下,容器内的压力-时间曲线表现出两个峰值,这是因为管道内的二次爆炸导致排气效率下降,增加了容器内的湍流强度。当静态活化压力为 0.7 巴时,30、50 和 70 三种直径的排气孔压力分别下降了 11.34%、24.38% 和 26.86%。而 Φ = 1.0 和 Φ = 1.4 时的 Pmax11 相近,其他通气孔直径则没有这种现象。当通风口直径与风道直径不一致时,两种标准的计算结果都比较保守。然而,在这些测试条件下(通风口直径:30-70 毫米,静态活化压力:0.7-1.75 巴),NPFA 68 的计算结果保守范围为 3.3-11,而 EN14491 的保守范围为 1.6-15.7。NPFA 68 的结果更加稳定和集中,因此这些条件更适合氢气排放的工业安全设计。
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来源期刊
CiteScore
7.20
自引率
14.30%
发文量
226
审稿时长
52 days
期刊介绍: The broad scope of the journal is process safety. Process safety is defined as the prevention and mitigation of process-related injuries and damage arising from process incidents involving fire, explosion and toxic release. Such undesired events occur in the process industries during the use, storage, manufacture, handling, and transportation of highly hazardous chemicals.
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