不同风速条件下村镇木结构建筑防火间距的数值模拟研究

Numerical Simulation Analysis of Fire Separation Distance of Rural Timber Structure Buildings under Different Wind Speeds

目的 探究风速对木结构建筑防火间距的影响规律,为我国村镇木结构建筑火灾防治提供参考。方法 采用PyroSim火灾动态模拟软件对西南地区典型穿斗式木结构建筑的火灾发展过程进行数值模拟,探索不同风速条件下的温度、热辐射通量密度的变化规律,揭示风速对木结构建筑防火间距的影响规律。结果 数值模拟计算结果表明:当燃烧时间为600 s时,木结构建筑进入燃烧充分发展阶段,且起火房间上方处的温度和热辐射通量密度值最高。木结构建筑防火间距随着风速的增加而增加,且在风速为4 m/s时出现极大值;当风速高于4 m/s时,热量加剧扩散并导致防火间距出现降低的趋势;对于采用不同品种建筑木材建造的木结构建筑,当风速为0~5 m/s时,数值模拟计算的木结构建筑防火间距值为4.24~8.22 m。结论 综合考虑地形、地势以及大气环境等不确定因素的影响,西南地区村镇木结构建筑的防火间距应大于12 m。

To provide reference for the fire prevention and control of timber structure buildings in villages and towns in southwest China,the influence of wind speed on the fire separation distance of timber structure buildings was explored.Using PyroSim fire dynamic simulation software,the fire development process of typical chuan-dou type timber structure building was numerically simulated,and the influence of wind speed on the temperature,the thermal radiation flux density and the fire separation distance of timber structure buildings was revealed.Simulation results show that when the burning time reaches 600 s,the timber structure building enters the stage of full combustion development,and the temperature and thermal radiation flux density above the burning room are the highest.The fire separation distance of timber structure buildings increases with the increase of wind speed,and the maximum value appears when wind speed is 4 m/s.When the wind speed is higher than 4 m/s,heat intensifies diffusion and leads to appear a trend of decreasing fire separation distance.When the wind speed is 0~5 m/s,the numerical simulation results show that the fire separation distance of timber structure buildings built with different types of wood is 4.24~8.22 m.Considering the influence of uncertain factors such as terrain,topography and atmospheric environment,the fire separation distance of rural timber structure building in southwest China should be greater than 12 m.