水平火灾实验炉试验与模拟分析

基于改进热平衡法,结合天然气燃烧的特点,采用火灾动力学模拟软件(FDS)构建水平火灾实验炉的数值模型,进行混凝土双向板火灾试验模拟研究.结果表明:通过控制燃料的供应速率控制燃烧机的输出热功率,可以实现水平火灾炉升温曲线与ISO 834的标准火灾升温曲线接近,模拟平均炉温与试验平均炉温最终误差为2.2%(22 ℃);水平炉烟道口温度高于平均炉温约87 ℃,与实际火灾实验炉烟道口频繁损坏现象吻合,因此,在实验炉设计中,应提高烟道与炉墙连接区域的设计耐火极限;FDS模拟得到的火灾炉内部及楼板受火面温度场呈不均匀分布,符合火灾实验炉各热电偶测点实测升温曲线不同的规律,温度场数据可用于研究非均匀温度场对混凝土板力学性能的影响.

Experiment and Simulation of Horizontal Fire Test Furnace

Based on the improved heat balance method and combining the characteristics of natural gas combustion, a numerical model of horizontal fire experimental furnace was established by the fire dynamics simulator(FDS), and a simulation study of the two-way concrete slab under fire test was carried out. The research results show that: controlling the output thermal power of the burners by fuel supply rate, the temperature rise curve of the simulated horizontal fire furnace can be close to the standard temperature rise curve of fire in ISO 834, and the final error between the simulated and experimental average furnace temperatures is 2.2%(22 ℃); the simulated flue temperature of the horizontal furnace is about 87 ℃ higher than the average furnace temperature, which is consistent with the frequent damage of the flues in the furnace. Therefore, in the design of the experimental furnace, the design fire resistance limit of the connection area between the flue and the furnace wall should be increased; the temperature field inside the fire furnace and upon the slab fired surface obtained by the FDS simulation is nonuniformly distributed, which conforms to the different temperature rise curves of the thermocouple measurement points in the real two-way concrete slab fire test. The temperature field data simulated by FDS can be used to study the effect of nonuniform temperature field on the mechanical properties of concrete slab.