【作者】 张村峰；

【导师】 霍然； 周允基；

【作者基本信息】 中国科学技术大学 ， 安全技术及工程， 2006， 博士

【摘要】 水喷淋系统是大型建筑中常用的消防设施。火灾发生时，从喷头喷出的大量液滴通过对流作用不断冷却烟气，烟气的浮力大大降低，使得其它消防子系统特别是排烟系统的性能受到很大影响。在一些内部净空高度很大的建筑中，这一现象尤其突出。研究水喷淋与烟气的相互作用，分析水喷淋作用时烟气层的流动状态，正是解决上述问题的关键所在。 本文的工作围绕水喷淋与烟气层的相互作用问题展开，包括三个方面：一是热烟气作用下闭式喷头的响应特性；二是水喷淋与烟气的相互作用；三是水喷淋与自然排烟共同作用是烟气的运动特性。 研究的第一部分是热烟气环境中闭式喷头的响应特性。本部分首先分析在几种不同火源条件下喷头的响应时间，给出了稳定火源和t²火源时喷头晌应时间的拟合公式。而后，分析了喷头启动的可能性问题：启动喷头的临界火源功率。结果表明，喷头响应时间和启动喷头的火源功率受诸多因素的影响。这些因素包括：喷头的安装高度、环境温度、火灾增长方式、响应时间常数以及喷头与火源中心的水平距离等。 第二部分围绕水喷淋与烟气的相互作用展开。 引入合理的假设，本文推导了液滴在烟气中运动的描述方程，并采用无量纲分析方法对方程进行简化。表明无量纲温升主要由烟气层初始厚度、无量纲喷头工作压力和喷头物理结构决定。通过实验发现，当喷头工作压力大于0.5MPa时，水喷淋作用后烟气准稳态的平均温升与无量纲压力之间的依赖关系可以通过幂指数函数（?）_g／ζ=a（?）_d^b进行描述。系数a的大小由喷头的几何结构确定，系数b与喷嘴直径的4次方成反比。 在Bullen的基础上，采用烟气—空气交界面薄层上单位体积内液滴对烟气的拖曳力D′_d，L与单位体积烟气的浮力B′_g，L之比作为判据，分析水喷淋作用后烟气层的稳定性。通过一系列实验，给出了D′_d，L／B′_g，L的值与水喷淋工作压力之间的更多还原

【Abstract】 There are often sprinkler systems in modern buildings. The water droplets spray out from sprinkler nozzles when there is a fire. Due to the cooling effect of water spray, the smoke temperature will decrease and then the smoke buoyancy will be reduced. The performance of other fire protection sub-systems will be affected greatly. This situation becomes very significant in some high ceiling clearance building. To study the interaction of water spay with smoke is the key issue to solve the problem.The aim of this thesis is to answer the three questions. The following aspects will be included: the performance of sprinkler in high ceiling clearance buildings, the interaction of water sprinkler and smoke, the smoke movement under sprinkler and venting.In the first part, the performance of sprinkler in high ceiling clearance buildings, the activation time of sprinkler under fire is discussed. An equation of sprinkler activation time is present. Then the possibility of sprinkler activation, critical heat release rate to activate the sprinkler head, is discussed. It has been shown that the activation time and critical heat release rate are affected by many parameters such as installing height of sprinkler head, environment temperature, the fire increase rate, RTI, the horizontal distance between sprinkler head and fire center, etc..In the second part, the interaction of water sprinkler and smoke has been analyzed.A theory based on dimensionless analysis has been developed to deduce a correlation on the smoke temperature increase under water sprinkler spray. It has been found the following parameters will affect the value of smoke temperature: initial smoke layer height, sprinkler head更多还原