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为研究室内火灾的外部燃烧现象,该文应用FDS(fire dynamic simulator)程序,采用大涡模拟(LES)湍流模型,对穿透风对外部燃烧火焰的影响进行了数值模拟研究。计算结果解释了Law的经验公式与Klopovic的实验观测之间的矛盾,并且给出Law经验公式的适用范围。计算结果显示,存在两个穿透风的临界速度当穿透风风速大于第一临界速度时,Law的关于外部燃烧火焰高度的公式定性正确;当穿透风风速大于第二临界速度时,Law的关于外部燃烧火焰长度的公式定性正确;数值计算得到的火焰宽度随风速的变化趋势与Law经验公式的预测结果相反,但与Klopovic的实验观测一致。
In order to study the external combustion phenomenon of indoor fire, this paper uses the large dynamic eddy simulation (LES) turbulence model to simulate the influence of penetrating wind on the external combustion flame by using FDS (fire dynamic simulator) program. The calculation results explain the contradiction between Law’s empirical formula and Klopovic’s experimental observation and give the applicable range of Law empirical formula. The results show that there are two critical velocities of penetration wind. When the penetration wind velocity is higher than the first critical velocity, Law’s formula on the height of the external combustion flame is qualitatively correct. When the penetration wind velocity is greater than the second critical velocity The formula for the length of external combustion flames is qualitatively correct. The calculated trend of flame width with wind speed is opposite to that predicted by Law empirical formula, but consistent with Klopovic’s experimental observations.