Transition from smoldering to flaming fire in cotton is investigated experimentally for five different sample sizes. Two different modes of transition are identified: early and late transition. Early transition to flaming occurs when smoldering combustion forms a hot glowing core inside a sample. As the smoldering burns through to the outside of the sample, air moves more easily into the core, resulting in a change in smoldering direction from reverse to forward smoldering, causing increased heat production and flaming. Late transition to flaming occurs occasionally after most of a sample is consumed by smoldering, and where randomly appearing glowing spots ignite flammable vapor from smoldering processes.

The current setup consists of cotton samples where one side of the sample is situated next to a lightweight concrete block forming a boundary. Cotton samples with density 80 kg/m³ with dimensions equal to or larger than 0.45 m · 0.45 m · 0.15 m high, consistently give early transition to flaming, while smaller samples have early, late or no transition. By identifying an experimental set-up with a sample size that assures transition from smoldering to flaming, the transition phenomenon can be studied in even more detail.

针对五个不同的样本量，对棉花中从闷烧到燃烧的转变进行了实验研究。确定了两种不同的过渡模式：早期过渡和晚期过渡。当阴燃燃烧在样品内部形成炽热的炽热核时，会发生早期燃烧。随着阴燃燃烧到样品的外部，空气更容易移入芯部，从而导致阴燃方向从逆燃变为正燃，从而导致热量产生和燃烧增加。在大多数样品被阴燃消耗后，偶尔会发生向火焰的后期转变，并且在随机出现的发光点点燃了阴燃过程中的可燃蒸气。

当前的设置包括棉花样本，样本的一侧位于形成边界的轻质混凝土块旁边。密度为80 kg /m³且尺寸等于或大于0.45 m·0.45 m·0.15 m的棉花样品始终可以早期燃烧，而较小的样品则具有早期，晚期或无过渡。通过确定具有确保从闷烧到燃烧的过渡的样本量的实验装置，可以更详细地研究过渡现象。