XPS板外墙外保温系统温度效应的数值模拟

Numerical simulation for temperature effect of external thermal insulation system with XPS board

为研究XPS板保温材料在不同季节温度应力的变化情况,在典型外保温墙体温度场计算的基础上,采用傅里叶(Fourier)方程及能量守恒定律建立理论模型,选取XPS板外墙外保温系统三个施工方案进行数值模拟:方案1为30 mm胶粉聚苯颗粒贴砌XPS板;方案2为10 mm胶粉聚苯颗粒贴砌XPS板;方案3为外墙薄抹灰.对外墙外保温系统墙体各层材料的力学行为进行分析,结果表明:夏季墙体整体受到压应力,涂料饰面层一天中应力变化范围为-0.34^-0.02 MPa,易产生膨胀离鼓现象;冬季墙体整体为拉应力,变化范围大概为0.12~0.26 MPa,开裂的风险比较大;方案1温度梯度最小,保温效果最好,优于方案2和方案3.

To study the change of thermal stress of XPS board thermal insulation material in different seasons,a theoretical model was proposed with both Fourier equation and lawof energy conservation based on the calculation of temperature field of typical external thermal insulation wall. Three construction schemes of external thermal insulation system with XPS board were selected and the numerical simulation was carried out.In the scheme 1,the 30 mm powder polystyrene particles stuck to XPS board. In the scheme 2,the 10 mm powder polystyrene particles stuck to XPS board. In the scheme 3,the thin plaster for the external wall was performed. The mechanical behavior of wall material in each layer in the external thermal insulation system was analyzed. The results showthat whole wall subjects to compressive stress in summer,the stress for the coating layer changes from- 0. 34 M Pa to- 0. 02 M Pa within a day,and the expansion from the wall is easy to occur. Whole wall subjects to the tensile stress in winter,the stress changes from 0. 12 M Pa to 0. 26 M Pa,and the cracking risk is relatively large. The scheme 1 has the minimum temperature gradient and the best thermal insulation effect. Therefore,the scheme 1 is better than both scheme 2 and scheme 3.