动边界作用下地铁火灾烟气蔓延与危害性演化的规律及控制策略研究

Boundaries of flow field and heat have characteristics of dynamic change in metro internal environment system. They directly affect the dynamics behavior of subway fire and toxic smoke spread, poison migration and its harmfulness evolution process to passengers. So far, it is very limited that research on fire characteristics under the action of dynamic changing boundary in subway and further more researches are needed to be carried out. Based on the action of dynamic changing boundaries on the underground air environment, this project takes complex subway as the object to study some laws of fire safety problems. The first is to analysis the changing rule about those changinging boundary factors, such as the traveling train and the moving crowd flow, as well as the airflow induced by those factors in subway. Secondly, the influence on the development process of subway fire is to be researched, which is caused by the dynamic boundary factors and their induced airflow, and the mechanism and law of evolution of special fire behaviors as well as the key influencing factors are to be revealed under the action of dynamic changing boundaries. Thirdly, fire smoke difussion characteristics and its coupling action with the crowd evacuation movement will be researched under the dynamic boundary conditions and the action of multi field coupling and multiple factors driving, such as wind field, heat and mass transfer. The prediction model of space-time evolution of smoke spreading and the crowd evacuation model are to be established in metro fire. The forth is to study the influence of the dynamic changing boundaries on the migration process of the smoke poison and asphyxia from the smoke fumes in fire. The space-time changing rule of the smoke harmfulness under the dynamic changing boundaries in metro is studied so as to reveal the toxic constituents of fire smoke and its space distribution and their time-varying rule and anoxia suffocate process. The last one is to study and put forward the control strategy about the subway fire based on the coupling effect between the dynamic underground environment and smoke spreading process. All of these above will directly provide theoretical guidance and support directly for the optimization of the fireproofing design of metro with complex construction, safety evaluation and emergency disposal. They are of great significance to establish a safety guarantee system for complex subway operation.

地铁内部环境系统的流场边界和热边界具有动态变化的特征，直接影响地铁火灾的动力学行为、烟气蔓延、毒物迁移及其危害性演化过程。目前有关动边界作用下的地铁火灾问题的研究非常有限。本课题基于动边界对地铁空气环境的作用，分析地铁中人群流动和列车运动等动边界因素及其诱导气流的变化规律，进而研究动边界因素及其诱导气流对地铁火灾发展过程的影响，揭示动边界作用下特殊火行为的发生机制、演化规律及关键影响因素；研究动边界条件下，多场耦合和多因素作用驱动的火灾烟气输运特性及其与人群疏散运动的耦合作用，建立火灾烟气输运的时空演化预测模型及人群疏散模型；研究动边界对火灾烟气毒物迁移规律及缺氧窒息过程的影响，揭示动边界下火灾烟气危害性的时空变化规律；研究提出基于烟气输运与动态环境间耦合作用的地铁火灾控制策略，直接为优化地铁防火设计、安全评价及应急处置提供理论指导和支撑。课题研究对建立地铁运营安全保障体系具有重要意义。

地铁内部环境系统的流场边界和热边界具有动态变化的特征，直接影响地铁火灾的动力学行为、烟气蔓延、毒物迁移及其危害性演化过程。目前有关动边界作用下的火灾问题的研究非常有限或深度不足。例如，受运动列车影响的车站和隧道火灾、隧道内运动列车的车体火灾和车厢内部火灾等。.本课题基于动边界对地铁车站和隧道内空气环境的作用，通过研究列车运动对空气流动和传热的影响，得到了列车正常行驶、减速进站、停站及加速驶离车站这一过程所诱导的列车风与自然通风及机械通风等多因素耦合作用下，地铁车站站台热环境的动态变化规律；同时，通过隧道火灾试验及研究动边界下的地铁火灾动力学特性以及多场耦合和多因素作用驱动下的火灾烟气流动，揭示了列车运动及机械通风对车站、隧道和列车火灾烟气输运特性的影响规律。.进一步地，通过研究动边界下火灾烟气危害性特别是烟气毒性的时空变化规律，基于元胞自动机的仿真分析得到了考虑火灾烟气对人体的毒性作用以及视野受限条件下的人员疏散规律；同时，基于社会力模型和烟气扩散模型进行了人员疏散模拟分析，揭示了考虑火灾烟气影响与不考虑烟气作用的人员疏散过程的差异。.最后，通过研究烟气输运与动态环境间的耦合作用，重点针对隧道列车火灾这一极易造成乘客伤亡的高风险火灾场景进行分析，揭示了隧道中列车在车体发生火灾或车厢内部出现火灾时仍继续运动、非着火车辆驶经着火静止车辆附近等若干情况下的烟气输运规律；进而通过研究列车运动速度对车体火灾燃烧特性和车厢内烟气扩散过程的影响，提出了基于速度优化和通风排烟模式的地铁火灾控制策略。.研究成果的科学意义主要在于：较为全面地探讨了动边界作用下地铁火灾燃烧特性产生变化的一般规律，特别是隧道内运动体自身火灾的一般规律以及隧道内非着火运动体对静止火源火灾燃烧特性的影响规律。研究结果直接为优化地铁防火设计、安全评价及应急处置提供理论指导和支撑，对建立地铁运营安全保障体系亦具有重要意义。