液氢泄放状态对连续泄漏扩散安全性影响研究

针对低温液氢在生产、储存、运输过程中可能发生从管道泄漏的问题,开展了数值模拟研究。以英国健康与安全实验室(HSL)的液氢连续泄漏实验为验证模型,采用Mixture两相流模型,对比研究了低温液氢不同泄放状态(泄漏流量和泄漏高度)对周围环境燃爆和低温伤害范围的影响,分析了可燃云团与低温云团在不同泄放状态下的扩散范围及形态,结果表明,在泄漏一段时间后,流场达到准稳态,场内参数基本维持不变;泄漏流量越大,可燃云团和低温云团在下风向运动距离越远,表面积越大;泄漏高度对云团的换热方式和扩散形态有很大影响,当泄漏源高于地面时,在近场云团以气液两相流向地面沉降,在远场,云团密度逐渐低于环境空气密度,表现为轻气扩散。

Influence of liquid hydrogen release state on safety of continuous leakage and diffusion

Liquid hydrogen leakage caused by spontaneous damage of tanks or rupture of pipelines poses a hazard to human beings because liquid hydrogen is cryogenic and combustible. Numerical simulations were performed to predict the leakage and dispersion behavior of liguid hydrogen. Based on liquid hydrogen release tests conducted by the HealthSafety Laboratory(HSL),a mixture flow model was developed. The impact of explosion and low temperature damage range on the surrounding environment were investigated under different conditions(mass flow rate,source height). The spread scope and patterns of flammable cloud and cold-effect cloud were analyzed.The results show that the hydrogen cloud reaches a quasi-steady state after a period of leakage,and the cloud fields remain unchangeable. The larger the flow rate,the farther the flammable cloud and cold-effect cloud move in the downwind direction,and the larger the cloud surface area. Different leakage heights have a great influence on the heat transfer mode and diffusion behavior of the cloud. When the source height is above the ground,the heavy mixture flows to the ground,then behaves as light gas when the cloud density becomes lower than ambient air density.