试样放置角度与外加辐射强度对可碳化固体表面火蔓延的影响

选取了尺寸为400mm×90mm×3mm质地较为均匀的白木作为研究对象,对不同试样放置角度和不同外加辐射强度作用下的火焰高度、火蔓延速率和失重速率等火蔓延参数进行了测量,以研究试样放置角度和辐射强度对可炭化固体表面火蔓延的作用规律。研究发现,试样表面的火蔓延速率随辐射强度的增加而增加。当角度在负角度范围内时,角度的变化对火蔓延速率的影响不大,当角度在正角度范围内时,火蔓延速率随着角度的增加而迅速上升。试样失重速率随着辐射强度以及试样放置角度的增加而增加。火焰高度会随着外加辐射强度的增加而增加,并与试样失重速率的0.4次方呈正比关系。

Fire Spread over Charring Materials: Influence of the Sample Orientation and External Radiant Intensity

In this paper,whitewood sheets in size 400mm×90mm×3mm have been selected as the typical charring material,in order to explore the characteristics of the flame spread under different circumstances,especially with different external radiant intensities and different angles of orientation.We measured the flame spread rate on the surface of the sample,the weight loss rate of the sample and the flame height.Results show that the flame spread rate increases as the external radiant intensity and the angle of orientation increase.For the negative angles,the increase of the angle only results in a slight increase of the flame spread rate,while for the positive angles,the increase of the angle results in a great increase of the flame spread rate.Similarly with the flame spread rate,the weight loss rate of the sample increases as the external radiant intensity and the angle of orientation increase as well.With the external radiant intensity added,the flame height would increase.The relation between the mass loss rate of the sample and the flame height is similar with that proposed by Zukoski.