基于火灾随机性的高大空间烟气温升研究

发布时间：2018-10-12 08:34

【摘要】：高大空间建筑作为一种重要的建筑形式广泛应用于建筑设计中,如候车厅、航站楼、礼堂等,其建筑规模大、空间高、结构特殊、火灾危险性高,对火灾的预防和救援提出了新的要求。火灾烟气温升会影响建筑结构安全、人员疏散、灭火救援等,且火灾发展是确定性与随机性共存的过程,但其随机性并非杂乱无章、毫无规律的,火灾发展过程的随机性因素一般会遵循一定的统计规律。因此,研究高大空间建筑在火灾随机性作用下的烟气温升有重要实际意义。本文首先采用方差分析方法,研究了多种因素对高大空间烟气温升的影响显著性大小。结果表明,对高大空间烟气温度影响最为显著的因素为火源功率,在随机性分析中,应重点分析影响火源功率的参数随机性。基于火灾动力学理论和实体火灾实验研究了高大空间烟气温升特性,实验结果表明在火源中心线区域,火焰区温度波动幅度大于羽流区,浮力羽流区随着羽流高度的增加,温度逐渐降低。在顶棚射流区域,随着空间点远离火源中心线,烟气温度呈现不断降低趋势,具有明显的非均匀分布特征。同时,根据实验结果,验证了参数化温升模型在预测高大空间火灾烟气温升方面的适用性。在进行高大空间温升随机性分析时,将影响温升的各参数分为确定性参数和随机性参数,研究了随机性参数分布概率密度函数。通过调研得出车站类高大空间建筑火灾荷载密度服从正态分布,通过资料查阅与分析,得出材料可燃性系数服从均匀分布,火灾过火面积和火灾增长系数服从对数正态分布。根据随机性参数概率分布,采用拉丁超立方抽样法确定随机性场景组,分析了最大热释放速率、火源等效直径、火源中心线最高温升的均值、标准差、概率密度(PDF)、累积概率(CDF)等。得出火源中心线最高温升服从对数正态分布,对数均值5.8697,对数标准差0.31396,拟合得到了火源中心线最高温升概率密度函数。通过抽样分析研究了距火源中心线不同距离处烟气最高温升概率分布,得出最高温升服从对数正态分布,拟合得到各距离处最高温升概率密度函数。通过案例分析,说明了高大空间烟气温升概率分布研究在建筑火灾安全评价中的应用。根据临界温度判据,对高大空间钢结构构件失效概率进行分析,得到案例中钢结构构件的失效概率。为了方便地进行不同面积、高度、火灾荷载的建筑烟气温升概率分布抽样计算与分析,开发了“基于火灾随机性的高大空间烟气温升及结构失效分析”程序。
[Abstract]:As an important architectural form, tall space architecture is widely used in architectural design, such as waiting hall, terminal building, auditorium and so on. It has large scale, high space, special structure and high fire risk. New requirements are put forward for fire prevention and rescue. Fire smoke temperature rise will affect the building structure safety, personnel evacuation, fire rescue and so on, and the fire development is a process of certainty and randomness, but its randomness is not random and irregular. The random factors in the process of fire development generally follow a certain statistical law. Therefore, it is of great practical significance to study the smoke temperature rise of tall space buildings under the action of fire randomness. In this paper, the influence of various factors on flue gas temperature rise in large space was studied by means of variance analysis. The results show that the most significant factor affecting the flue gas temperature in large space is the power of the fire source. In the randomness analysis, the randomness of the parameters affecting the power of the fire source should be emphasized. Based on the theory of fire dynamics and solid fire experiments, the characteristics of flue gas temperature rise in large space are studied. The experimental results show that the temperature fluctuation in the flame zone is greater than that in the plume zone, and the buoyancy plume region increases with the plume height. The temperature is decreasing gradually. In the roof jet area, with the space point far away from the central line of the fire source, the flue gas temperature shows a decreasing trend, with obvious non-uniform distribution characteristics. At the same time, according to the experimental results, the applicability of parameterized temperature rise model in predicting fire smoke temperature rise in large space is verified. In the analysis of the randomness of temperature rise in large space, the parameters affecting temperature rise are divided into deterministic parameters and random parameters, and the probability density function of random parameter distribution is studied. Through investigation and investigation, the normal distribution of fire load density clothing for tall and large space buildings of station type is obtained. Through the reference and analysis of data, the uniform distribution of material flammability coefficient, the logarithmic normal distribution of fire overfire area and fire growth coefficient clothing are obtained. According to the probability distribution of random parameters, the random scene group is determined by Latin hypercube sampling method. The maximum heat release rate, the equivalent diameter of the fire source, the mean value and standard deviation of the highest temperature rise in the center line of the fire source are analyzed. Probability density (PDF), cumulative probability (CDF) et al. The logarithmic normal distribution of the highest temperature rising clothes of the central line of the fire source, the logarithmic mean 5.8697 and the logarithmic standard deviation of 0.31396 are obtained. The probability density function of the highest temperature rise of the central line of the fire source is obtained by fitting. The probability distribution of maximum temperature rise of flue gas at different distances from the central line of fire source is studied by sampling analysis. The maximum temperature rise probability density function is obtained by fitting the logarithmic normal distribution of maximum temperature rise. The application of probability distribution of flue gas temperature rise in building fire safety evaluation is illustrated by case analysis. According to the critical temperature criterion, the failure probability of steel structure members in large space is analyzed, and the failure probability of steel structure members in the case is obtained. In order to conveniently calculate and analyze the probability distribution of flue gas temperature rise in buildings with different area, height and fire load, a program of "smoke temperature rise and structural failure analysis based on the randomness of fire" was developed.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU998.1;TU834

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