可燃物填充比对火蔓延影响的实验研究

提出了一种可精确控制燃料床填充比的方法。以刨花为燃料,开展了可燃物填充比对火蔓延影响的系统性实验研究。分析了火焰长度、火焰倾斜角、火蔓延速率、质量损失速率和热流密度随填充比的变化规律。研究发现,随填充比增大,火焰长度逐渐减小,火焰倾斜角逐渐增加,导致火焰热辐射降低、火蔓延速率减小。当填充比小于0.06时,燃料消耗率接近于1;当填充比在0.06～0.08内变化,燃料消耗率突然降低,说明此区间存在一个临界填充比,使得燃料床由热薄型向热厚型转变。

Experimental study on the effect of fuel packing ratio on fire spread

This paper presented a new method to control the packing ratio of the fuel bed accurately. The influence of fuel packing ratio on fire spread was studied systematically using wood excelsior as fuel. The variation of flame length, flame tilt angle, fire spread rate, mass loss rate and heat flux with the packing ratio were analyzed. It is found that as the packing ratio increases, the flame length decreases while the flame tilt angle increases, which leads to the decrease of flame radiation and fire spread rate. When the packing ratio is less than 0.06, the fuel consumption efficiency is close to 1. When the packing ratio changes between 0.06~0.08, the fuel consumption efficiency suddenly decreases. It is indicated that there is a critical packing ratio among this range, which makes the fuel bed change from thermally thin to thermally thick.