【作者】 杨淑江；

【导师】 徐志胜； 马恒；

【作者基本信息】 中南大学 ， 消防工程， 2008， 博士

【摘要】 烟气是火灾中造成人员伤亡的最主要因素,建筑的消防安全离不开对火灾烟气的控制与管理。基于火灾过程的复杂性,火灾烟气容易受到外界因素的影响,如环境风。本文针对有风条件下的烟气流动与控制开展了理论模型分析、数值模拟和模型实验研究,完成的研究工作以及获得的主要成果如下:1.建立了水平风作用下的羽流质量流率的数学模型,分析了水平风对羽流质量流率的影响,采用因次分析法获得了水平风下羽流质量流率的预测表达式,为建筑火灾中烟气产生量的正确计算提供了理论参考;2.建立了环境风实验平台,并于平台中开展了不同环境风速下的小尺寸自然排烟实验,为建筑自然排烟系统的设置及系统在环境风条件下的性能表现预测提供了实验数据支持;3.提出了总风压系数的概念,并将其用来评价环境风对自然排烟效果的影响,获得了自然排烟临界失效风速与总风压系数的幂次关系;4.发展了针对有风条件下室内火灾自然排烟过程计算的双区模型,模型预测与实验结果符合良好,可以将其作为自然排烟系统设计的辅助计算工具。实际火灾中火源及环境条件千差万别,建筑防排烟系统的设置应具体问题具体分析。基于此,本文的研究有望能对实际建筑防排烟系统的设计提供模型和数据参考。更多还原

【Abstract】 Smoke is the most dangerous factor to personnel in building fires. Smoke management is essential for a fire protection system of a building. However, smoke spread is easy to be affected by surrounding conditions, such as winds. Theoretical analysis, numerical simulations and model tests are carried out to study smoke movement and control in this dissertation. Achievements of this study are listed as the following:1. A mathematic model for predicting mass flow rate of plume affected by horizontal wind is proposed. Influence of surrounding wind on mass flow rate of plume is discussed and dimensional analysis is adopted to obtain the expression of mass flow rate of tilted plume. The expression can be referred for calculating smoke generation in a fire.2. A testing platform with surrouding wind is set up and series of small-scale experiments on natural exhaust under different velocities of wind are carried out. The results can be referred for design of smoke management system and assess the performance of natural exhaust systems under surrounding winds.3. Overall pressure coefficient is proposed to evaluate the influence of surrounding wind on natural smoke exhaust. A critical velocity of invalidation at which the natural exhaust will lose its function is reduced and is found to be proportional to -1/2 power of the absolute value of overall pressure coeffiecient.4. A simplified two-layer zone model is developed to simulate smoke filling in a compartment with natural smoke exhaust under surrounding wind. Experimental verification shows that the model is precise enough for predicting the process of natural smoke exhaust under surrounding wind. The model is recommended for the authority to use as a tool in evaluating the performance of static smoke exhaust system.The conditions of actual fire vary much from each other. Therefore, configuration of smoke management system of a building should accord with the demand of the building. According to this point, the work of this thesis is helpful to design of smoke management system of a building for its model and data reference.更多还原