安全壳隔间壁面冷凝诱发的氢气分层行为研究

A study on the stratification behavior of hydrogen gas induced by condensation on the wall surface of the containment compartment

为了评估安全壳隔间冷壁附近的蒸汽冷凝对氢气聚集风险的影响,本研究采用数值模拟的方法对局部隔间内含氢混合气体的迁移和聚集现象开展分析。结果表明,在足够高的氢气和蒸汽浓度条件下,蒸汽冷凝会诱发近壁区的混合气体形成浮力流。当隔间内释放气体的Fr小于临界值时,高浓度的氢气会在近壁区浮力流的驱使下聚集于隔间顶部;反之,隔间内的氢气会被混合均匀。当冷凝诱发浮力流的组分浓度被满足,蒸汽冷凝会增强安全壳局部隔间内高浓度氢气聚集的稳定性,隔间内氢气分层所需的临界Fr明显高于无冷凝条件。本文研究结论可为核电站严重事故下的氢气安全行为提供理论参考。

In order to evaluate the effect of steam condensation near the cold wall of the containment compartment on the risk of hydrogen accumulation,numerical simulation was carried out to analyze the migration and accumulation of hydrogen-containing mixtures in the local compartment.The results show that under the condition of sufficiently high hydrogen and steam concentration,steam condensation will induce the formation of buoyant flow of mixed gas in the near-wall region.When the Fr of gas released in the compartment is less than the critical value,high concentration hydrogen gas will gather at the top of the compartment under the driving force of buoyancy flow near the wall.On the contrary,the hydrogen gas in the compartment will be mixed evenly.When the required component concentration conditions for buoyancy flow induced by condensation are met,condensation will enhance the stability of high concentration hydrogen gas accumulation in local compartments of the containment.The critical Fr required for hydrogen stratification in the compartments is significantly higher than that under the condition of no condensation.The conclusion of this paper can provide theoretical reference for hydrogen safety behavior under serious accidents in nuclear power plants.