自动喷水灭火系统喷水强度概率分布特性及其控火性能研究

Water density probability distribution and fire control capability of sprinkler system

喷水强度是体现自动喷水灭火系统控火能力的重要参数,具有不均匀性和不确定性。传统的喷水强度设计主要考虑喷头的流量和保护面积,没有考虑其分布特性,对系统控火性能的影响。因此本文将喷水强度分布特性引入自动喷水灭火系统的控火性能研究。以公称口径为15 mm的传统下垂型玻璃球洒水喷头的喷水强度分布实验为基础,建立了包含径向距离和喷头工作压力等参数的喷水强度分布模型,采用蒙特卡罗方法获得了喷水强度的概率分布特性。参照不同危险等级场控火所需的喷水强度参数和不同喷头开启个数下的有效控火百分比,分析了喷水强度概率分布特性对控火性能的影响。研究结果表明,喷水强度概率分布特性对控火性能有重要影响,随径向距离的增加,喷水强度出现较小值的概率增大,控火性能下降,在某些危险较大的场所不能达到控火作用。对于同一危险等级场所,控火性能随着喷头安装间距减小而增强。研究方法可为合理评估喷头适用范围、优化喷头布置提供参考。

Water density is the deterministic parameter for fire control capability of sprinkler system, but with the characteristics of non-- uniformity and uncertainty. Conventional research on sprinkler system addressed the protection area and flow rate. In this paper, water density distribution characteristics was used to study the fire control capability of sprinkler, and the parametric model of water density distribution involving the parameters of radical distance and operating pressure was established, based on the experimental data of conventional pendant sprinkler of 15mm orifice. The probability distribution of water density was obtained by using Monte Carlo simulation. The effect of water density distribution characteristics on fire control capability was studied by referring to the required critical water density for various class fire control using sprinkler and percent of effective fire control with number of sprinkler nozzles activated. Results indicated that the fire control capability was significantly affected by the probability distribution of water density. The probability of smaller water density increased with radical distance and fire cannot be controlled under some serious fire situations. For a certain fire risk class, the fire control capability decreased with the radical distance and increased with the installation distance of sprinkler nozzles. Such research methodology can be referred for assessing sprinkler application area and optimizing sprinkler nozzle installation.