【摘要】 多孔固体可燃物含水率不连续分布会对其阴燃过程产生影响，并可能会促进阴燃向明火转变。该文对自然对流条件下含水率突变的锯末材料阴燃转明火过程进行实验研究。实验样品前半部分保持干燥，后半部分含水率增加(干基含水率：11.83%～60.35%)。实验结果表明，当后半部分干基含水率小于19.30%时，阴燃能够自维持传播；当后半部分干基含水率在20.40%～51.69%之间时，阴燃蔓延过程中会在含水率突变处形成有利于气体积聚的空隙，并发生向明火的转变；当后半部分干基含水率大于53.57%时，不会发生转明火现象。固体内部温度和气体产物演化过程表明，含水率突变处发生阴燃转明火是高温、突变处形成的空隙和可燃气体积聚共同作用的结果。更多还原

【Abstract】 The discontinuous distribution of moisture content(MC) of porous solid fuels can affect the smouldering process and even trigger the transition from smouldering to flaming. In this paper, the smoldering experiments of pine sawdust with discontinuous moisture contents under natural convection were conducted. The first half of the sample was dry, while the second half was wet(dry based MC: 11.83%～60.35%). The results showed that when the dry-based MC of the second half was less than 19.30%, smoldering propagated self-sustainably; when the dry-based MC of the second half was between 20.40% and 51.69%, a crevice conducive to gas accumulation formed at the MC mutation, and smoldering transited to flaming(STF); when the dry based MC of the second half was higher than 53.57%, no STF occurred. From the evolutions of temperatures and combustible gases, it can be concluded that transition from smoldering to flaming was caused by high temperature, the formed crevice and the combustible gases concentrated in the crevice at the same time.更多还原