Abstract In a Fire Extinguishing System (FES), it is important to maintain the design concentration of the gaseous agent in the enclosure for a specific time. An inert agent, in particular, can maintain an O2 concentration below 15% by maintaining a gaseous concentration above the threshold value for a specified time, which is called the retention time. However, the current theoretical model for retention time in the inert agent reflects only species diffusion due to differences in gravity and molecular weight but not due to temperature. Therefore, this study analyzed species diffusion with temperature using IG-541, a representative inert agent. A numerical analysis was done with the assumption of a stable flow field (no bias pressure from HVAC systems), and the discharge step was eliminated for a simplified approach. As a result, the retention time of the inert agent was sensitive to species diffusion with temperature. The diffusion flux was used to analyze the influence on the inert agent temperature according to Fick's law and the slope ω according to the interface thickness. The numerical analysis could provide a basis for a new model that takes into account temperature in the future.

中文翻译：

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温度对惰性试剂保留时间影响的数值研究

摘要 在灭火系统 (FES) 中，重要的是在特定时间内保持外壳中气态剂的设计浓度。特别是惰性试剂可以通过将气体浓度保持在阈值以上指定的时间（称为保留时间）来将 O2 浓度保持在 15% 以下。然而，目前惰性剂中保留时间的理论模型仅反映了由于重力和分子量的差异而不是由于温度的差异而导致的物质扩散。因此，本研究使用具有代表性的惰性试剂 IG-541 分析了物种扩散随温度的变化。数值分析是在假设流场稳定（HVAC 系统无偏压）的情况下进行的，并且为了简化方法取消了排放步骤。因此，惰性试剂的保留时间对物质随温度的扩散很敏感。扩散通量用于根据菲克定律和根据界面厚度的斜率ω分析对惰性剂温度的影响。数值分析可以为未来考虑温度的新模型提供基础。