科学技术的进步和时代需求促使超高层建筑迅猛发展，中国现存和在建的超高层建 筑数量呈逐年增加的趋势，约 2020 年左右，中国将成为全球范围内超高层建筑最多的 国家。随着超高层建筑的增多，一些又“瘦”又“高”具有明显“竖井”的特点的超高 中庭数量也呈逐年增加趋势，并受到了设计师和人们的一致认可。然而，由于中庭空间 高度较高且截面积较小，火灾时易形成烟囱效应，导致烟气范围迅速扩大，因此如何设 计超瘦高中庭的烟气控制系统以保证超瘦高中庭的消防安全是研究人员不得不面对的 新挑战。 本文根据超瘦高中庭的空间特征，分析超瘦高中庭建筑的火灾特点和影响烟气运动 的相关因素，并针对影响中庭自然排烟的因素，基于相关理论公式和 FDS 火灾模拟软 件，采用理论和数值模拟结合的方法得到了超瘦高中庭能够进行自然排烟的临界条件。 由中庭火灾烟气蔓延规律定义了羽流临界区高度，基于羽流质量变化规律分析及中 性面模型，对超瘦高中庭羽流进行了研究，且与 FDS 数值模拟结果进行了对比验证。 分析了超瘦高中庭分别在单独热压情况下以及外界风与热压同时作用下自然排烟的临 界条件，并研究了超瘦高中庭线性温度分层和区域分层情况下对自然排烟效果的影响。 关键词，超高中庭；自然排烟；中性面；热障效应沈阳航空航天大学硕士学位报告 II Abstract The advancement of science and technology and the demand of times have led to the rapid development of super high-rise buildings. In China, the number of super high-rise buildings existing and under construction is increasing with high speed and apparently this will lead China to be the highest country by 2020, which is predicable from recent years new appeared buildings. Together with the more and more high–rise buildings, the characteristics of narrow and high also emerged, and obviously, the style of the Super Tall and narrow Atrium has gained its popularity among both designers and customers. However, one thing cannot be ignored is that special atrium has smaller cross-sectional area and is much higher and narrow, the characteristic of easily formed chimney effect will lead to the rapid expansion of smoke in empty space, so how to design smoke-control system in super tall and narrow Atrium and ensure the safety of people during evacuation is a new challenge which is also cannot be avoid for researchers. Based on the analysis of the characteristics of super tall and narrow atrium, this paper analyzes the characteristics of the fire and the factors which affect the smoke movement. Based on the relevant theoretical formula and FDS the critical condition for the natural smoke exhausting in the ultra-leaning atrium was analyzed by the method of combining the theory and numerical simulation. The critical plume height is defined by the regular pattern of fire spreading in atrium, Based on plume characteristic of smoke and neutral plane model ,the plume of the super tall and narrow-thin atrium is studied, which has been verified with FDS.The critical conditions of the natural smoke exhaust under the condition of the buoyancy and the external wind and buoyancy are analyzed respectively .The effects of the natural smoke exhaust under the linear temperature stratification and the regional stratification in super tall and narrow-thin atrium is also respectively studied.沈阳航空航天大学硕士学位报告 III Keywords: Super-high atrium;Natural exhaust;Neutral Plane;Stratification effect沈阳航空航天大学硕士学位报告 IV 目 录 第 1 章 绪论...........................................................................................................1 1.1 研究背景.......................................................................................................................1 1.1.1 中庭建筑发展情况................................................................................................2 1.1.2 中庭的分类............................................................................................................3 1.1.3 中庭特点及火灾危害性.......................................................................................4 1.1.4 超瘦高中庭的定义...............................................................................................5 1.1.5 自然排烟的特点...................................................................................................7 1.2 研究现状......................................................................................................................8 1.2.1 烟羽流研究现状...................................................................................................8 1.2.2 烟气运动的影响因素现状研究...........................................................................9 1.3 研究内容和技术路线.................................................................................................11 1.3.1 研究内容.............................................................................................................11 1.3.2 技术路线.............................................................................................................12 第 2 章 自然排烟相关理论模型概述................................................................13 2.1 火灾烟气流动基础.....................................................................................................13 2.1.1 普通羽流模型......................................................................................................13 2.1.2 羽流半径随高度变化的模型..............................................................................14 2.1.3 烟气温升模型......................................................................................................15 2.2 竖井羽流特点.............................................................................................................15 2.2.1 竖井烟气流动模型概述......................................................................................15 2.2.2 竖井火灾发展过程.............................................................................................16 2.3 超瘦高中庭自然排烟规律分析................................................................................17 2.3.1 单纯烟囱效应下运动分析.................................................................................17 2.3.2 中庭烟气流动壁面粘滞力.................................................................................21沈阳航空航天大学硕士学位报告 V 2.3.3 中庭热环境温度分布对排烟的影响.................................................................21 2.3.4 环境风对建筑物的附加压差.............................................................................22 2.4 超瘦高中庭自然排烟理论........................................................................................23 第 3 章 超瘦高中庭数值模型............................................................................26 3.1 FDS 简介.................................................................................................................... 26 3.2 超瘦高中庭全尺寸数值模型.....................................................................................26 3.2.1 中庭模型尺寸概述.............................................................................................26 3.2.2 中庭排烟系统设置情况.....................................................................................27 3.2.3 火源功率的选取.................................................................................................27 3.2.4 火源特征直径的选取.........................................................................................28 3.2.5 自然排烟面积的规定.........................................................................................28 3.2.6 外界风的设定.....................................................................................................29 3.2.7 温度梯度的设定..................................................................................................29 第 4 章 超瘦高中庭临界羽流入口高度的因素分析....................................... 30 4.1 竖井和中庭羽流区发展特点的比较........................................................................30 4.2 中庭近火源区的羽流质量流率.................................................................................31 4.3 临界羽流入口高度影响因素的数值模拟.................................................................32 4.3.1 中庭截面尺寸对中庭羽流的影响......................................................................33 4.3.2 高度对羽流的影响.............................................................................................35 4.4.临界羽流入口高度和竖井温度分布模型.................................................................38 第 5 章 超瘦高中庭自然排烟临界条件分析....................................................42 5.1 中庭单纯热压影响排烟规律.....................................................................................42 5.1.1 自然排烟速率.....................................................................................................42 5.1.2 临界排烟口面积.................................................................................................44 5.1.3 临界压力条件.....................................................................................................45 5.1.4 案例理论计算.....................................................................................................46 5.1.5 FDS 数值验证..................................................................................................... 53沈阳航空航天大学硕士学位报告 VI 5.2 外界风条件下中庭排烟情况.....................................................................................63 5.2.1 外界风共同作用下的中庭中性面模型.............................................................64 5.2.2 外界风对中庭排烟效果影响实例分析.............................................................64 5.2.3 临界风速大小.....................................................................................................66 5.2.4 FDS 数值验证..................................................................................................... 69 5.2.5 临界压力和风速的大小.....................................................................................69 5.3 热障效应对自然排烟效果的影响.............................................................................73 5.3.1 热障效应工况设置..............................................................................................73 5.3.2 线性分层对自然排排烟的影响..........................................................................74 5.3.3 区域分层对自然排烟的影响..............................................................................75 5.3.4 热障效应对排烟的影响.....................................................................................77 结论.......................................................................................................................79