不同环境下外墙保温缺陷表征规律的数值模拟研究

Numerical Simulation Research on the Characterisation Law ofExternal Wall Insulation Defects in Different Environments

以外墙保温缺失墙体为研究对象,基于数值模拟探究其在不同室内外温差和室外风速下的表征规律。选取标准中规定的缺陷区域相对面积及能耗增加比作为表征指标,同时提出温度异常区域相对面积及墙体能耗增加比作为新的表征指标,分别从墙体内、外表面对热工缺陷进行表征。通过分析缺陷墙体表面温度分布及传热量计算方法差异,探究各类型指标在不同环境下的表征结果差异产生原因。结果表明,由于现阶段标准中对缺陷区域划分及能耗增加比的简化计算,导致同一缺陷在不同环境下的表征结果出现明显波动,外表面缺陷区域相对面积和内表面缺陷区域能耗增加比波动幅度分别达到2.5%和6.6%,存在无法准确表征热工缺陷的问题。缺陷侧的温度异常区域相对面积及墙体能耗增加比在不同环境下的表征结果较为稳定,适宜作为热工缺陷的表征指标。

Based on numerical simulation,the characterisation law is investigated for a wall with missing external wall insulation under different indoor-outdoor temperature differences and external wind speed.The relative area of the defective area and the increase ratio of the energy consumption in the defective area specified in the standard are selected as the characterisation indices,while the relative area of the temperature anomaly area and the increase ratio of the energy consumption in the wall are proposed as new characterisation indices to characterise the thermal defects from the inside of the wall and the outside of the wall.By analysing the differences in temperature distribution and heat transfer calculation methods for defective wall faces,the reasons for the differences in characterising the different types of indicators in different environments are explored.The results show that due to the simplified calculation of the defect area division and the energy consumption increase ratio in the current stage of the standard,the results of characterising the same defect in different environments vary widely,with the variation of the relative area of the defect area on the outer surface and the energy consumption increase ratio of the defect area on the inner surface being 2.5%and 6.6%,which cannot accurately characterise the thermal defects.The relative area of the temperature anomaly region on the defective side and the increase ratio of the wall energy consumption are more stable in different environments,which is suitable for the characterisation of thermal defects.