火灾环境下钢管构件热响应特性

Thermal Response Characteristics of Steel Tube Members Under Fire Conditions

利用ISO9705标准火灾实验系统模拟火灾环境,对钢管构件的温升及温度分布进行实验研究.测量火源的热释放速率、温度场及钢构件的温度等参数,分析不同火源功率与位置下热环境的特点及钢构件的温度响应规律.结果表明,钢的导热系数较大,但由于所用建筑结构钢材大部分都是薄壁构件,截面积很小,使得构件沿长度方向的内部传热远小于沿径向与外界的热交换,因此,沿长度方向构件温度分布具有较大的不均匀性,主要取决于其表面热烟气温度的变化.

The ISO9705 standard fire test system was applied to design the building fire environment to perform the experimental study on the temperature risings and temperature distributions of steel tube members. The parameters, such as heat release rate of fire, temperature field and temperatures of steel tubes, were measured. The characteristics of thermal environments and the rules of temperature responses of steel members under different fire powers or at different fire source locations were analyzed. The results indicate that although the conductive coefficient is large, the steel elements in the building are mainly thin-wall steel members with small cress-section areas, and as a results, the internal heat exchange of the steel members is much smaller than the heat exchange with external boundary at the radius direction. Therefore, there exists a great non-uniform distribution of temperature in the longitude of the member, which is mainly determined by the variation of temperature of hot smoke near the steel member surface.