【摘要】 在聚亚安酯材料的稳定阴燃中,通过实验研究了阴燃向有焰燃烧转化的机制.在富氧条件下,阴燃向有焰燃烧转化还需具备两个条件:一是有足够高的温度,要求高于约400℃;二是有足够高的热解可燃气浓度.在阴燃达到热平衡稳定状态对应的最高温度———峰值温度时(>400℃),第一个条件是自动满足的.当温度高于约350℃且在氧气充足的情况下,聚亚安酯材料发生更快速的有氧热解反应,此时释放的热解可燃气满足第二个条件.因此,沿着阴燃方向加风,或者在自然对流条件下增大氧的扩散量,都可以导致向有焰燃烧的转化.对于逆向阴燃,风速增加也导致向有焰燃烧的转化,规律同正向阴燃一致.更多还原

【Abstract】 Experiments had been conducted to study the mechanisms involved in the transition from smoldering to flaming combustion of polyurethane foam. With abundant oxygen, the transition requires two other conditions:high temperature (>400 ℃) and high density of combustible gases. In steady propagation of smoldering,temperature condition is satisfied automatically.The gases density condition is satisfied when the material decomposed more quichly in abundant oxygen with temperature higher than 350 ℃.Both the forced forward smoldeing and natural convection smoldering could transfer to flaming combustion as the oxygen supply enlarged.Also, the forced opposed smoldering could transfer to flaming combustion with the increasing air flow,similar to the forced forward smoldering.更多还原