热释放率对单室开口中性面影响程度的数值模拟

单室火灾的研究一直是建筑火灾研究的重点,文章运用火灾模拟软件FDS对ISO9705标准房间火灾进行了模拟研究.讨论了火源为不同液体反应物时,不同燃料的燃烧表面积与单位面积热释放率的关系,结果表明FDS模拟单位面积的热释放率受网格粗细的影响并随燃烧表面积的增加而逐渐趋于稳定;将开口处温度、速度曲线和Steckler的实验结果进行比较分析,表明模拟结果曲线与实验结果曲线符合较好;改变热释放率的大小,分析开口处的流动特点,通过对理论计算结果与模拟结果进行分析表明,开口处中性面高度随火源热释放率的增加而逐渐降低.

Simulation of a compartmentalized fire breaching its container under the impact of different heat release rates

Research on fires within a compartment is central to understanding building fires. Making use of the software fire dynamics simulator (FDS), a simulation of an ISO9705 standard room fire was conducted. First, different combustible materials were considered, and then the relationship between the surface area available to burn and the heat release rate was discussed. The result shows that the heat release rate per unit is impacted by the unit's placement in the rooms grid, and the larger the surface area burning, the steadier the heat output. Temperature and velocity curves for the simulation and for Steckler's test were then compared. The result shows that the curves of the simulation comply with the curve of Steckler's test. Changes to the heat release rate were seen when the compartment was breached, as this affects characteristics of flow. The higher the designed heat release rate of the fire, the lower the height of the neutral plane at the opening.