林火蔓延初期的增长模型与室内模拟实验研究

分析了均匀水平燃料床从一个点火源的着火过程，建立了林火蔓延初期的增长模型，采用数值法计算了蔓延初期的加速度与速度的变化趋势，并通过室内模拟实验，在燃料床上测取了林火初期蔓延速度。通过对着火后１００ｓ的实验数据与计算结果的比较，说明所使用的初期蔓延过程的增长模型在物理上是合理的。从实验结果分析看出，在着火后２０ｓ以内，及在着火的８０ｓ－１００ｓ锥形火焰向环形火焰转化时，火蔓延速度与加速度剧烈地波动。

Investigation on the Growth Model and Simulation Experiment of Early Forest Fire Spread

The ignition process of a fire from a point in plain and homogenous fuels bed are analyzed.The growth model of fire spread is studied.The acceleration and rate of fire spread are numerically calculated.The experiment data of the rate of fire spread after ignition were measured in the fuel bed in the laboratory with non-wind.By comparing the calculated result with the experimental data of fire spread rate,we can find that the growth model is reasonable.In 20 s and between 80 s and 100 s after ignition,the rate and acceleration of fire spread violently fluctuate near the average.According to the calculating results,it needed about 32 minutes to approach the steady spread rate after ignition.Because of the limitations of conditions,it is difficult to simulate the whole process in the laboratory.