Prediction of Heating Conditions and Thermal Response of Structural Members Exposed to Localized Flies

通过实验和数值研究，获得了以下结果：(1)火灾暴露的局部性对柱火灾安全性的有效性通过对局部火源作用下的钢柱进行模型试验，发现其最大温升可降低到邻近均匀火焰加热的柱的50%-90%。(2)对局部加热作用下梁和柱上的热流分布进行建模和制表。采用钢结构和多孔丙烷燃烧器进行的模型试验表明，对于不同的结构和结构/火灾配置，热流密度沿梁/柱的分布是唯一的依赖关系。实验关联式已经通过一系列全尺寸热通量测量得到了验证。将数值流体动力学应用于火源上方钢梁热流场的再现，通过对火焰辐射模型的改进，使再现误差在30%以内。(3)局部加热下金属结构温度响应的数值计算有限差分法已应用于局部火灾下钢柱的温度场预测。热传递系数等经验常数已针对参考试验进行了调整。这种密闭室使实验结果重现得很好。

Through experiments and numerical studies, following results have been obtained.(1)Demonstration of the effectiveness of the localizedness of fire exposure for the fire safety of columnsThrough model experiments on a steel column exposed to a localized fire source, it has been found that its maximum temperature rise be reduced to 50 - 90 % of the column adjacent to an even flame heating.(2)Modeling and tabulation of heat flux distribution along a beam and a column exposed to a localized heatingModel experiments using steel structures and porous propane burners have yielded sole dependence of heat flux distribution along a beam/ column for respective configurations and structure/fire configurations. The experimental correlations have been validated against a series of full-scale heat flux measurements. Numerical fluid dynamcs has been applied to the reproduction of the heat flux field of the steelbeam above a fire source, which has resulted in th e reproduction within the error of 30 % by the improvement of the modeling of flame radiation.(3)Numerical cabulation of temperature response of metal structure exposed to a localized heatingFinite difference method has been applied to the prediction of the temperature field of a steel column exposed to a localized fire. Empirical constants such as heat transfer coeffifent have been tuned against a reference test. The cabulation has resulted in a fine reproduction of the experimental results.