摘要
以双区模型思想为基础,对环境风作用下建筑室内火灾自然排烟过程进行理论分析和数值模拟研究。引入风压系数计算环境风对建筑各外表面形成的附加风压,在此基础上对排烟口和补气口处内外压差进行分析,同时对烟气流动分别进行质量和能量守恒分析,建立了有风条件下水平自然排烟口烟气质量流率的数学表达式,并给出了烟气层高度和温度的理论计算方法。实际采用水平自然排烟系统时,应对补气口位置进行合理选择,尽量选择处于迎风面的补气口进行自然补气,使总风压系数为正,以提高排烟效率。
Based on the two-layer zone model,theoretical consideration on mass flow rate of smoke vent in natural smoke exhaust of enclosure fire under surrounding wind was performed with a horizontal natural vent.Numerical simulations with a CFD software package（Fire Dynamics Simulator,FDS） were also carried out to get the regularities of dependence for parameters of smoke layer（interface height and temperature） on surrounding wind and the position of air inlet.Wind pressure coefficient was introduced to describe the extra wind pressure on the surfaces of building.Pressure difference across the smoke vent and air inlet under surrounding wind were corrected with the extra wind pressure.Conservation of mass and energy of smoke layer was analyzed and expressions were obtained on mass flow rate of horizontal natural smoke vent under surrounding wind.Overall wind pressure coefficient（difference of wind pressure coefficient at air inlet and vent） affects smoke exhaust rate to some extent.Calculation of temperature and interface height of smoke layer was consequently provided.In practice while designing natural smoke exhaust system,smoke vent should be located rationally,for example,open the air inlets in windward wall for natural air makeup to enhance the efficiency of extraction with positive overall wind pressure coefficient.
出处
《中国安全生产科学技术》
CAS
2012年第12期63-67,共5页
Journal of Safety Science and Technology
关键词
环境风
水平自然排烟口
质量流率
风压系数
surrounding wind
horizontal natural vent
mass flow rate
wind pressure coefficient
