防火树种阻火特性的实验研究

Experimental Study on the Characteristics of Fire-resistant Tree Species

以木荷作为防火树种 ,首先利用热重装置分别研究了其树干和枝叶的热解失重过程 ,从得到的热重曲线TG、DTG中发现 ,伴随着温度的升高 ,试样发生了三次失重高峰 ,并且 5 0 0℃时的残留物不及其初始重量的 10 %。然后在燃料床上以松针为燃料 ,分别模拟了 2 0°和 30°等小坡度情况下地表火的蔓延过程 ,通过分析热电偶记录下来的温度场分布 ,研究了火蔓延过程中防火树种在火焰和坡度作用下的阻火特性和阻火机理 ,结合其热解特性的研究 ,论证了水分析出是防火树种发挥阻火性能的关键因素 ,得到一些对生物防火技术研究有用的结论 ,为更好的利用和发展生物防火技术来预防和控制大规模森林火灾提供了理论基础。

In the current experiments, schima superba is made to simulate the fire resistant tree species and its thermal decomposition processes are studied by using dynamic thermogravimetry. From the plots of the samples' mass loss against temperature shown as both TG and DTG curves, it's found that there are three main mass loss processes along with the temperature rising and at 500℃ the residue of the samples is less than 10% of initial mass. Furthermore, the courses of forest fire spread in small slope of 20°and 30° have been simulated in fuel bed by using pine needle as fuel. Based on the analysis of the temperature field recorded by thermocouples, characteristics and mechanism of the fire resistant tree species under the effect of flame and slope in forest fires have been studied in the present paper. With the results of thermal decomposition experiment, it is demonstrated that water vaporizing is the vital factor of the reactivity of fire resistant tree species in forest fires. Some other useful conclusions are also described in the paper. This investigation would make theoretical support for the work to develop the biological fire prevention technique, which is widely applied to preventing and controlling the large scope forest fires.