Hydrogen safety: Pressure Peaking Phenomena-unignited releases

The aim of this study was to validate a model for predicting overpressure arising from accidental hydrogen releases in areas with limited ventilation. Experiments were performed in a large-scale setup that included a steel-reinforced container of volume 14.9 m3 and variable ventilation areas and mass flow rates. The pressure peaking phenomenon, characterized as transient overpressure with a characteristic peak in a vented enclosure, was observed during all the experiments. The model description presented the relationship between the ventilation area, mass flow rate, enclosure volume, and discharge coefficient. The experimental results were compared with two prediction models representing a perfect mix and the real mix. The perfect mix assumed that all the released hydrogen was well stirred inside the enclosure during the releases. The real mix prediction s used the hydrogen concentration and temperature data measured during experiments. The prediction results with both perfect mix and real mix showed possible hazards during unignited hydrogen releases.

本研究旨在验证一款用于预测通风受限区域内氢气意外泄漏引发超压现象的模型。实验采用一套大型试验装置，该装置包含容积为14.9立方米的钢加固容器，且可灵活调整通风面积与质量流量。所有实验均观测到压力峰值现象：该现象表现为带通风结构的封闭空间内出现带有特征峰值的瞬态超压。该模型给出了通风面积、质量流量、封闭容器容积与排放系数之间的定量关联。研究将实验结果与两款预测模型的计算结果进行对比，这两款模型分别基于完全混合假设与实际混合假设。完全混合模型假设：在氢气泄漏过程中，容器内部所有泄漏出的氢气均被充分搅拌均匀。实际混合模型的预测过程则依托实验中测得的氢气浓度与温度数据开展。两款模型的预测结果均表明，未被引燃的氢气泄漏场景下存在潜在安全隐患。