【作者】 彭小勇；

【导师】 李桦；

【作者基本信息】 国防科学技术大学 ， 力学， 2007， 博士

【摘要】 当在公共大空间建筑内部纵火、用生化毒气等制造突发性事件,伤亡者中大多是由于吸入毒气所致,毒气一旦在大空间内蔓延,是非常难以控制的,将带来严重的危害和后果。由于毒性气体对人体的伤害,除其生化物性外,取决于毒气的浓度和对人体的作用时间。因此,保证室内人员在最短的时间内到达相对安全的区域,尽可能减少毒气对人员的危害,必须有效的控制毒气的扩散范围,降低疏散通道空气中毒气的浓度。本文针对公共大空间建筑可能的突发事件模式,在研究毒气自由扩散机理的基础上,探讨不同形式气流组织的应急通风技术控制毒气扩散的能力,发展具有防范多种突发事件模式和不同性质毒气的应急通风技术,研究工作围绕以下几个方面开展:1、系统阐述了大空间建筑内部突发事件主要实施模式(纵火模式(纵火产生毒气);毒气模式(毒气弹袭击);人工布撒模式(人工布撒毒性物质挥发产生毒气))中毒气的类型、危害和扩散的特征;分析了大空间建筑中现行上排式应急通风系统控制这些突发事件模式中毒气扩散的适用性和不足。在上述基础上,提出了局部控制毒气扩散和全面排出毒气相结合的控制-排出式应急通风技术思路。2、根据突发事件室内气流和毒气扩散的低速不可压缩流动特性,为克服这类流动问题控制方程的刚性问题,建立基于预处理法非定常低速流动N-S方程的数值方法。3、针对大空间建筑突发事件毒气运动特性,确定了以数值模拟研究为主、实验研究为辅的研究方案,其中纵火模式采用缩比模型盐水实验方法,毒气弹袭击和人工布撒毒性物质模式采用数值模拟方法。同时建立基于预处理法考虑组分输运方程、非定常低速湍流流动问题的数值模拟方法。4、采用数值模拟方法,对毒气弹模式和人工布撒模式,研究毒气在大空间建筑内部自由扩散特性,以及门开启方式、室内障碍物对毒气自由扩散的影响。5、采用数值模拟方法,对人工布撒模式,研究毒气随室内空调气流扩散的特性,以及通风空调系统将毒气输送到室内各区域的作用。6、采用数值模拟方法研究了大空间建筑常规上排式应急通风和控制-排出式应急通风对毒气扩散和输运过程的控制能力,研究比较了不同送、排风口气流参数对控制毒气扩散的作用。数值模拟证实了本文提出的控制-排出式应急通风技术思路的正确性和可行性,它能克服上部排风方式对不同性质毒气适用性差等缺陷,为大空间建筑防范突发事件毒气危害应急通风工程设计提供了新的设计思想和技术手段。7、采用缩比模型盐水实验方法,研究了无排烟、自然排烟和机械排烟时,火灾烟气在大空间建筑中的流态和烟气层厚度的发展过程。同时,应用PIV技术测试了自然排烟时室内气流流场分布。更多还原

【Abstract】 When the emergencies happen due to accident fire or poison gas made by people in the large space of public buildings, the most of casualties are hurt by toxic gas inhaled. Once the poison gas spreads in large spaces, it is very difficult to control and will result in severe harm and consequences. Besides the characters of the poison gas, the damage to person’s body lies on the concentration of poison gas and the duration of staying in poison gas. Therefore, we must effectively control the diffusing range of poison gas and reduce its concentration in the evacuation route way, ensuring that people indoor can arrive to safe places during the minimum time and the damage to person becomes as minimal as possible. Based on study on mechanism of poison gas’ free diffusion, this paper researches the different technologies of emergent ventilation and their capabilities of controlling the poison gas diffusion under the different modes of public emergences occurring in the large space of public buildings. Meantime, the paper has developed the technologies of emergent ventilation which can keep away many modes of public emergences and different poison gas. The research work includes as follow:1. The types of poison gas, the damage to person made by poison gas and the characters of the poison gas diffusion are systematically set forth when public emergences happen, which are implemented under main modes (such as the poison gas made by setting fire, by gas bomb attack or by artificially distributing toxic substance directly) occurring in the interior of large spaces building. The applicability and shortages of the current up-exhaust technology of emergent ventilation are analyzed in controlling the poison gas diffusion in the large space building. On basis given above, the control-exhaust model technology of emergent ventilation, which can control the poison gas diffusion in the local area and discharge the poison gas completely, are put forward.2. According to the movement characteristic of air flow and poison gas in the large space, A numerical simulation method for unsteady low-speed flow N-S equations with preconditioned method has been developed. This method can eliminate stiffness of the equations in low-speed flow.3. According to the movement characteristic of poison gas in the large space, the research schemes combine both numerical simulation and experimental study. The mode of setting fire is studied through the method of small-scaled model salt-water experiment. The modes of gas bomb attack or artificially distributing toxic substance are researched through the method of numerical simulation. A numerical simulation method for unsteady low-speed turbulence flow equations and species transport equation with preconditioned method has been developed.4. Using the method of numerical simulation, under the modes of artificially distributing toxic substance, the characteristic of the poison gas free diffusing in the interior of large space buildings, and the effect of the poison gas diffusing implemented by the doors, barriers and so on are investigated.5. Using the method of numerical simulation, under the modes of artificially distributing toxic substance, the characteristic of the poison gas diffusing in the steady ventilating airflow indoor, and the effect on the ventilating and air-conditioning system transporting poison gas to the other area indoor are investigated.6. Using the method of numerical simulation, the ability to control poison gas diffusion and the transportation process adopting the conventionally up-exhaust technology of emergent ventilation or control-exhaust model technology of emergent ventilation in the large space building are studied. The effects on controlling the poison gas diffusion under different flow parameters of supply air or exhaust air are researched. It has been verified by numerical simulation that the control-exhaust model technology of emergent ventilation is correct and feasible. It can overcome the shortage that the up-exhaust technology lacks applicability to different poison gas, which offers new design idea and technological means in designing the emergent ventilation engineering of a large space building.7. Using the method of small-scaled model salt-water experiments, the flow pattern of the fire smoke and the developing process of the thickness of smoke layer in the large space building under the conditions of no smoke exhaust, smoke natural exhaust and smoke mechanical exhaust are researched. At the same time, the flow field of the indoor air is tested applying the PIV technology.更多还原