水蒸气对氢气燃烧影响的数值研究

核电站严重事故下，氢气的燃烧风险是影响安全壳完整性的重要因素，而水蒸气的存在对氢气、空气混合气体的燃烧会产生重要的影响。本文采用CAST3M软件，对局部小空间内氢气的燃烧特性以及水蒸气的影响进行研究。首先对THAI装置的典型实验工况进行模拟，表明了相关燃烧模型的可用性。然后将高度为6 m、直径为2.2 m的圆柱空间作为燃烧域，对其分别计算了8%、10%、12%氢气浓度下的燃烧，并与添加25%水蒸气的相应工况进行了对比。通过对燃烧域的温度、压力以及火焰传播速度的分析，表明添加水蒸气后燃烧产生的最大压力下降，火焰的最大温度下降，火焰传播的速度下降。研究表明，水蒸气的存在对氢气的燃烧具有抑制作用，能有效降低氢气燃烧产生的后果。

Investigation of Steam Effect on Hydrogen-air Combustion by Numerical Simulation

During severe accident in nuclear power plant ,the hydrogen‐air combustion is a main risk threatening the integrity of the reactor containment .However ,the existence of steam in hydrogen‐air mixture can cause some differences on consequence of combus‐tion .CAST3M software was used to simulate hydrogen‐air and steam‐hydrogen‐air combustion in small and medium scale geometry .Firstly ,a typical test case in T HAI facility was simulated to indicate that the relevant combustion model was applicable . Then ,a cylinder with the diameter of 2.2 m and the height of 6 m was used as combus‐tion chamber .T he hydrogen volume fractions of 8% ,10% and 12% in the hydrogen‐air mixture case were calculated respectively ,and the results with the same hydrogen frac‐tion and the steam volume fraction of 25% in the steam‐hydrogen‐air mixture case were compared .By analyzing the results of temperature ,pressure and flame speed with and without steam in the combustion chamber ,the steam in the hydrogen‐air‐steam mixture leads the peak pressure ,the peak temperature and the flame propagation speed to reduce significantly .According to this simulation ,steam can suppress hydrogen‐air combustion and reduce the combustion consequence .