湿热老化后膨胀型钢结构防火涂层导热系数数值计算

通过对已有多孔材料导热系数计算模型的总结和分析,提出了湿热老化后膨胀型钢结构防火涂层导热系数的计算模型。为考察该模型的计算精度,进行了湿热老化试验及隔热性能试验,测量涂层膨胀倍率、炭化层泡孔尺寸和钢板温度等数据。结果显示,湿热老化后炭化层泡孔尺寸增大导致涂层导热系数增大,隔热性能下降,钢板温度上升。利用本文试验测量数据(泡孔尺寸)计算炭化层导热系数,再根据炭化层导热系数的数值计算结果分析钢板温度,并将钢板温度的计算结果与试验结果进行对比,两者吻合良好,验证了膨胀型防火涂层导热系数计算模型的适用性。

Thermal Conductivity of Intumescent Coating Char after Hydrothermal Aging

This paper proposes an analytical method to calculate the thermal conductivity of fully expanded intumescent char after undergoing various cycles of accelerated aging. To investigate the accuracy of this thermal conduetivity model,hydrothermal aging tests and fire tests were conducted.Expansion ratio,poresize and steel temperature were measured.An obViOUS trend is that as the number of hydrothermal aging cycle increased,the pore sizes in the expanded intumescent chfir tended to become bigger.This has the effect of increasing the thermal conductivity of the intumescent char,reducing its thermal insulation performance and increasing steeI temperature.Using this thermal conductivity model and the measured bubble diameters for two types of intumescent coating after different cycles of hydrothermal aging,the intumescent coating inSUlated steel plate temperatures were numerically caIculated and compared with measured re Sults. The agreement was found to be generally satisfactory,suggesting that the thermal conductivity model is acceptable.