【作者】 李辛夷；

【导师】 付祥钊；

【作者基本信息】 重庆大学 ， 供热、供燃气、通风及空调工程， 2003， 硕士

【摘要】 火灾数值模拟研究是现代火灾科学研究的基础性方法。结合火灾实验研究，利用数值模拟方法来模拟中庭之类大空间建筑火灾过程，是当今火灾研究的前沿课题之一。本文通过火灾数值模拟，比较了不同的火灾模型的应用特点和适用范围。发现对于大空间建筑烟气流动及控制的分析若采用区域模拟方法是与实验事实有较大差异的；采用场模拟方法或混合模拟方法进行研究更能够反映出实际的情况。数值模型中火源的设计假若采用传统火源模型（稳态火源或者T2火）来描述，则当火灾的增长超过一定时间之后就会与实际情况产生越来越大的偏差。本文结合火灾相似模型实验研究，对中庭建筑火灾过程进行了数值模拟研究，建立了火区燃烧及蔓延过程与烟气流动过程相互耦合的气-固两相火灾模型。该模型充分考虑了火区燃烧与蔓延情况对烟气流动数值模拟的影响，从而可以更加准确地反映出火源释热率的变化等因素的影响，改善了中庭火灾烟气流动数值模拟的精度与可靠性。通过上述实验研究和数值模拟研究，发现当采用我国现行的《高层民用建筑防火设计规范》（GB50045-95）来指导中庭建筑的排烟系统设计时，在本文设计的火灾场景条件下（参照实际的中庭商场调研情况，即火灾载荷密度较大时），对于本文实验研究中所采用的相似模型及原型建筑，无论是采用自然排烟或者是采用机械排烟，其排烟量皆不足。因此，大空间建筑排烟系统的设计需要探索更加可靠的方法。本文的研究发现，单纯利用烟气层分界面高度的发展变化来评估中庭火灾过程的危险性和计算逃生时间值得商榷。应当结合烟气有害成分的浓度场分布来分析和评价烟气的危害性程度和烟气控制系统的效率。本文提出了采用气体传感器来研究烟气的蔓延和加强大空间建筑消防安全的技术措施。本文结合火灾各个分过程的特点深入地讨论了建筑火灾相似模型实验的适用范围，以及火灾相似模型实验与数值模拟研究的关系。并且运用理论分析的结果为指导，有效地提取了实验研究的数据，为数值模拟研究打好了基础。最后，本文讨论了针对特定的建筑火灾现象建立非线性动力学模型的可行性，并提出了新的研究思路和观点。本文还利用突变理论来建立火灾模型，考察了建筑火灾从阴燃状态向明火燃烧转化的过程中的关键因素。更多还原

【Abstract】 The computer codes for the simulation of fire are currently a fundamental methodology in modern fire research. In recent years, there are a lot of activities that focus on the simulation of atrium fire, which generally integrates with experimental approaches.This dissertation has surveyed the history of fire models in the 20th century and its newly developments. Through study those commercial software of fire, this paper has developed a new fire model that has fully considered the bilateral influence of combustion and heat and mass transfer between the solid phase and the gas phase in the fire field. Later on, a comparison of the calculations from different fire models with the experimental data has been conducted. Which bring up a conclusion that the zoon model is not agree with the facts of fire experiment, hence the field model or the combined model is better for the simulation of fires in a large volume building. The author found that the stable heat source presumption or the T2 design fire is also not agree with the experimental data. The simulation of fire in an atrium has shown that the new model is more accurate to predict the fire scenarios than any other models that include a general mathematical model of fires.After analyze the foundation of the current national code ( Code for Fire Protection Design of Tall Buildings GB500045-95) through experiments and fire simulations , the author has found that there are some limitations on the use of this national code for the designing of smoke management system in an atrium. This paper has been discovered that it is not enough when using the smoke layer interface height as a criterion to make an assessment on the safety rate in a building fire, or to calculate the egress time. It should combine the data of concentration field of hazard materials in smoke to analyze the effectiveness of the smoke management system.This paper also thoroughly discussed the characters and adaptations of the scale model experiment of fires and its relationship with the fire simulation.Based on the theory of nonlinear dynamics, the author present some new ideas of the application of these theories to the simulation of authentic fire phenomenon. As an<WP=6>example, the analyzing of the process of a smoldering fire change to a flame fire has been carried out, which utilize the catastrophe theory to develop a nonlinear dynamical fire model.更多还原