双火源条件下的XPS火蔓延速率研究

为研究挤塑聚苯乙烯泡沫板(XPS)双火源火焰迁移规律,在不同间距(0.5cm~8cm)的情况下,进行了竖直和水平方向的系列实验。研究发现:火蔓延速率和质量损失速率均随间距先上升后缓慢下降;在竖直方向实验中,火蔓延速率极值点右偏移于质量损失极值点。基于双火源条件下所得到的热解区传热系数,计算出火蔓延速率,进而分析火蔓延速率计算式中对流项和辐射项,得出火蔓延速率随间距的变化主要受控于传热系数。依据此结论解释了火蔓延速率和质量损失趋势相似但两者极值点偏移不同的原因。

Flame spread rate over two parallel extruded polystyrene (XPS) foam slabs

A series of experiments were conducted to explore the controlling mechanism of flame spread over two parallel slabs side-by-side in vertical and horizontal directions, with varying separation distance (d: 0.5 cm~8 cm). It was found that the flame spread rate and mass loss rate both increased firstly and then decrease with increasing separation distance. In vertical experiments, the extreme point in the curve of flame spread rate moved right to the x-direction relative to the mass loss rate. The convection coefficient in prolysis/preheated region was calculated, and the convective term and radiative term in the formula of flame spread rate was theoretically analyzed. It is concluded that the flame spread is controlled by the varied convection coefficient. Finally, the offset of extreme point and similar tendency of flame spread and mass loss rate are elucidated.