木材热解与着火特性试验研究

Experimental study on pyrolysis and ignition of wood

在自行研制的火灾固体可燃物热解与着火早期特性试验台上，对建筑装潢常用的几种木材以及森林常见的木材进行了热解和着火特性试验研究．试验木材尺寸为100mm×100mm×15mm，试验选择辐射热流强度范围为20～60kW／m^2．分别就不同含水率、不同氧气体积分数、木材的纹理方向、不同的材料、不同厚度以及外加辐射热流强度等6个方面，对木材热解和着火特性的影响进行了研究．结果表明，随着辐射热流的增加，着火时间缩短、着火温度下降；随着木材含水率的增加，着火时间延长；不同环境氧气体积分数对木材热解和着火特性影响很大．预测了木材着火时间，通过试验值和理论计算值比较，两者吻合较好．

Experiments on pyrolysis and ignition of several different woods widely used in the buildings or distributed in the forests were carried out on the self-developed apparatus for investigating pyrolysis and ignition of combustible materials. With slab-shaped samples of wood （100 mm×100 mm×15 mm） subiected to different heat fluxes ranging from 20 kW/m^2 to 60 kW/m^2, the influences of heat flux, moisture content, oxygen concentration, thickness and grain orientation on the pyrolysis and ignition of wood were examined. The experimental results showed that the responses of the ignition characteristics to the intensity of radiant heat flux were different. The ignition temperature and ignition delay time decrease with increasing radiant heat flux. The increasing moisture content increases the time for spontaneous ignition at a given radiation intensity. In addition, oxygen concentration is an important factor tending to affect on the pyrolysis and ignition characteristics at various heat fluxes. The predicted wood ignition time is properly compatible with the experimental results.