高层建筑火灾时走廊-前室缓冲区防烟机理研究

In high-rise building fires, there are some specific characteristics of the development of fire and smoke and the smoke control mode. It is well known that the smoke is mostly hazardous element in high-rise building fires, which including hot and toxic gases and making people choke and hurt. Form former study, the stack effect was not considered, so these mathematic models were not correct enough to describe the smoke diffusion rule, especial when the fire was located in different height. So this project is armed at the rule of smoke diffusing and control with different height. Firstly, the major influence elements will be analyzed, such as the structures, the height of the fire location, the wind, and so on. The research key point such as the passage, atria and stair well will be built, connected and considered as a whole to solve the problems. The mathematic model of the neutronsphere of the building will be built, which is charge with the fire growth and used to calculate the whole field. Secondly, the critical condition of the smoke stagnated in front of the atria will be discussed after adding the pressured air in the atria. The temperature, pressure and velocity of the smoke will be fitted to reveal the innate character. Thirdly, the vertical air flow will be added with exhausting fans. The efficiency of the vertical combination model will be compared with pressured model and discussed. Also the coupling model about the smoke and air flow will be concluded to make sure the control model reasonable. At the end the 'Corridor-Atria Buffer Zone' will be put forward. The adjust method of how to form the zone will be discussed. Also the system parameter such as temperature, pressure and velocity of the smoke and the air flow will be analyzed, and the mathematic model of critical condition of this zone will be concluded. In this model the evolution behaviors of smoke in the passage will be studied. This project could make the former formulas better, and it will complete the smoke control models and give the fire design some useful reference value.

在高层建筑这一特定结构中，火灾和烟气的发展及有控模式下的演化行为具有特殊性。课题通过分析影响烟气扩散的主要因素，对主要横向和纵向疏散通道如走廊、前室和楼梯间进行重点研究。根据典型长廊结构特点如长廊型、回廊等，建立随时间变化的高层建筑内气流的中性层数学模型，并根据其模型计算建筑内流场变化，揭示烟气扩散规律；分析其正压防烟主要缺点，揭示正压条件下的前室门口烟气滞止的临界条件，在此基础上提出横向水平疏散通道内的"垂向组合控制"模式及该模式下烟气与垂向气流的耦合模型。通过该控制模式使其形成"走廊-前室缓冲区"，并提出其临界态数学模型，研究此模式下其水平通道内烟气演化行为。现有的烟气控制模式未考虑建筑烟囱效应的影响，不能对其限制作用下的烟气行为进行描述，本研究可完善经典烟气运动理论在高层建筑中的不足；对于完善烟气控制模式和消防安全设计也具有参考价值。

在高层建筑这一特定结构中，火灾和烟气的发展及有控模式下的演化行为具有特殊性。课题分析了影响烟气扩散的主要因素，对主要横向和纵向疏散通道如走廊、前室和楼梯间进行了重点研究。根据典型长廊结构特点如长廊型、回廊等，建立了随时间变化的高层建筑内气流的中性层数学模型，并根据其模型计算建筑内流场变化，揭示了烟气扩散规律；分析了其正压防烟主要缺点，揭示正压条件下的前室门口烟气滞止的临界条件，在此基础上提出了横向水平疏散通道内的“垂向组合控制”模式及该模式下烟气与垂向气流的耦合模型。通过该控制模式使其形成“走廊-前室缓冲区”，并提出了其临界态特征，研究了此模式下其水平通道内烟气演化行为。现有的烟气控制模式未考虑建筑烟囱效应的影响，不能对其限制作用下的烟气行为进行描述，本研究完善了经典烟气运动理论在高层建筑中的不足；对于完善烟气控制模式和消防安全设计也具有参考价值。