坡度对山地火蔓延影响的实验研究

文章在坡度为 $ 0^{\circ}\sim40^{\circ} $的山地模型上开展火蔓延实验，研究不同的中心坡度和侧面坡度对火线轮廓、火线夹角、火焰长度和火蔓延速率（rate of fire spread，ROS）的影响，分析火焰对前方未燃烧的燃料的预热作用。研究发现：山脊火会形成水滴状火线，山谷火线在侧坡上呈V形；中心坡度和侧面坡度会对山地火蔓延行为产生重要影响，随着中心坡度增加，山谷火焰对流换热明显增强，ROS快速增加。

Fire spread experiments were carried out on mountain models with slopes ranging from $ 0^{\circ} $ to $ 40^{\circ} $. The effects of different central slopes and lateral slopes on flame line profile, flame line angle, flame length and the rate of fire spread (ROS) are studied, and the preheating mechanism of the fuel in the unburned area in front of flame was analyzed. It is found that ridge fire forms a water-droplet-shaped flame line, and valley flame line are V-shaped on lateral slopes. The central slope and lateral slope will have an important impact on the spread behavior of mountain fire. With the increase of the central slope, the convection heat transfer of the valley flame is significantly enhanced, and the ROS increases rapidly.