锥形量热仪确定聚合物材料导热系数的方法

通过对聚甲基丙烯酸甲酯聚合物材料在锥形量热仪实验条件下加热过程的分析和研究,建立了材料加热过程的数学模型。利用该模型来计算材料的平均导热系数,需要测量的物理量仅仅是物体表面或内部的温度,通过一次测试就可以得到不同温度范围内材料的平均导热系数,方法简单,可靠。利用文中的计算方法,得到PMMA在不同温度范围内的平均导热系数,结果表明,随温度范围的增加,材料平均导热系数值有增大的趋势。计算出的导热系数值在低温度范围与文献值比较接近。研究表明在高的温度范围内不能将传统测量的导热系数值用作火灾条件下材料的参数值。

Determining Thermal Conductivity of Polymer with Cone Calorimeter

The heat transfer of the poly(methyl methacrylate) was studied by the cone calorimeter at heat flux level of 50 kW/m2?to establish an essential physical model for the heating process in fire.A mathematical model for the heating process of polymer material was put forward.The mean thermal conductivity of polymer can be determined by computing the model with the temperatures measured on the surface or inside of the specimen as the required measuring data.The results indicate that the calculated mean thermal conductivity of poly(methyl methacrylate) increases with the expansion of temperature range.The thermal conductivity predicted by the method proposed here shows sufficient accuracy at low temperature range and can meet the requirement of engineering applications.The study shows that the thermal conductivity measured with traditional methods at low temperature range may be not appropriate for the use as an input parameter of material in fire.