低压下近熄灭极限区域纸火蔓延实验研究

摘要

In this study,experiments of flame spread over paper samples near extinction limits in sub-atmospheric pressure are carried out.A flammability map with O2concentration and pressure is generated in quiescent environment and the characteristics of flame spread rate with LOC versus pressure are analyzed.Experiments in different pressure with oxygen concentration of 43% are also studied.For a given oxygen concentration,the results show flame spread rate increases rapidly in near limits region.The pressure boundary between near limits and linear growth region is obtained by analyzing the flame spread rate data and data in literature.In addition,the changes of flame images near the pressure boundary are investigated. The heat transfer controlled energy of flame spread in different pressure regions is analyzed based on flame images and theory.%对低压下的近熄灭极限区域水平纸火蔓延进行了实验研究.通过降低环境压力和氧气浓度,确定了水平纸火蔓延的着火极限,并得出了在极限氧气浓度条件下的火蔓延速度变化规律.在相同氧气浓度下(43%)进行了不同压力的水平纸火蔓延实验.结果表明,火蔓延速度在近熄灭极限区域内非线性增加,通过比较分析前人火蔓延速度实验结果,确定了火蔓延近熄灭极限区域和线性增长区域的分界压力值.此外,得出了压力分界处的火焰变化特征,并根据火焰图像与理论分析,得出了不同区域内的火蔓延传热机制.