通过对膨胀阻燃聚丙烯材料在锥形量热仪实验条件下燃烧的分析和研究,建立了能够描述膨胀阻燃材料升温、燃烧过程的物理模型。同时考虑传质传热过程并结合膨胀速度的经验公式,建立了膨胀阻燃聚合物燃烧的数学模型。实验中测量了样品在膨胀燃烧过程中的样品厚度随时间变化规律。通过比较发现,模拟的样品厚度随时间变化曲线与实验结果吻合较好,模型比较可靠。模型还可模拟样品在火灾燃烧过程中的温度分布。
The heat transfer and burning behavior of the intumescent fire-retardant polypropylene were studied by using a cone calorimeter with heat flux levels of 25, 50 and 75 kW.m^-2, respectively, to establish an essential physical model for the intumescence process of the fire-retardant polypropylene during burning. Based on the assumption of the existence of an intumescent front between the char layer and virgin layer, a mathematical model describing the burning process of fire-retardant intumescent polymer was put forward. The calculating formula used for the intumescent velocity was presented and was applied to the model proposed. Meanwhile the thickness variation of the intumescent polypropylene during burning were measured and compared with the modeling results. The results show that the intumescent thicknesses predicted by the model are in fairly good agreement with the experiment results. The model was also used to predict the temperature distribution across the sample thickness during burning. The study shows that the presented model can appropriately describe the intumescent behavior of the polymer and numerically predict its intumescent thickness and the temperature distribution in it during burning.