【作者】 孙立新；

【导师】 闫增峰；

【作者基本信息】 西安建筑科技大学 ， 建筑学（建筑技术科学）， 2018， 博士

【摘要】 热湿耦合迁移对于外保温系统的长期性能有着至关重要的影响,而岩棉外保温系统又是近年来广泛应用的一种外保温系统类型,其热湿特性又与传统有机保温系统有着重大差异,开展岩棉外墙外保温系统的热湿耦合迁移及长期性能的研究具有重大的现实意义和理论价值。首先,本研究分析了外保温系统性能要求,针对岩棉薄抹灰外墙外保温系统的应用发展情况将其归纳为三种基本构造形式。结合现场工程调研和文献资料分析,将工程问题归纳提炼为热湿耦合长期作用的两大基础问题。基于传热和传质的特点和需求,将岩棉外保温系统三种基本构造模式凝练为热湿耦合分析用简化构造模型。模型的各个构造组成部分为（从室内侧至室外侧）:基层墙体、粘接层、岩棉层和抹面层,并假设层内为连续介质,材料均匀同性。简化构造模型的提出为热湿耦合分析奠定了现实基础,建立了理论分析与工程应用的可靠联系。其次,研究对热湿耦合计算所需的基础热湿物理性质进行了概述,分析了全面研究外保温系统核心组成材料的基础热湿物理性能参数对于本研究的现实必要性。研究测试了混凝土、岩棉、EPS、胶粘剂、抹面胶浆等外保温系统核心组成材料的物性参数,为后续的数值模拟研究等提供了数据支撑,奠定了研究基础。尤其是胶粘剂和抹面胶浆的液态水吸水系数和毛细饱和含湿量、比热等试验填补了国内相关研究的空白。在导热系数的测试分析中,研究发现了的测试系统误差,提出了接触热阻的修正方法,开展了温度和含湿量对建筑材料导热系数的耦合影响分析,建立了二元拟合方程。在平衡吸放湿的测试分析中,发现使用Feng模型对材料的平衡吸放湿曲线进行拟合的精度更高,重质材料吸放湿曲线并非完全一致,吸湿曲线时的平衡含湿量略低,放湿的平衡含湿量略高。轻质材料内部的绝对含湿量较少,因此平衡含湿量基本一致。第三,研究结合围护结构热湿耦合的传递规律和多孔介质的特性,对热湿耦合物理模型做了简化假设,并给出了岩棉外保温系统在热湿耦合计算时室内外的辐射、对流换热、水蒸汽和液态水（降雨）等边界条件和计算确定方法。基于传热传湿的连续性原理,结合边界条件和材料性能特点,以温度和相对湿度为驱动势对Luikov模型进行了改进,给出了岩棉外保温系统的热平衡方程和湿平衡方程,以及外保温系统一维/二维的热湿耦合迁移平衡方程。修正模型的提出解决了真正迁移驱动力的问题,也可以避免计算当中的不连续现象,利于反映外保温系统在环境中的变化,也便于与测试的热湿物理性能参数对接。该方法形式简单,十分易于理解和计算,又具备现实可行性,为后续的研究奠定了基础。同时,研究根据实际工况建立了三种典型构造模型,开展了不同气候、基层墙体、抹面层对系统含湿量的影响以及内表面结露分析比较,并得到了针对岩棉系统的热湿耦合作用下的构造设计原则和建议:1)液态水（降雨）对系统含湿量的影响远大于空气相对湿度的影响,采用稳态纯蒸汽扩散模型分析具有相当的局限性;2)岩棉系统应以湿份―进出一致‖为设计原则,以系统整体热湿迁移的观点统一考虑各个构造层的热湿物理性能的匹配性;3)宜根据降水量,增加对系统抹面层吸水性能的要求,以控制系统内的含湿量;4)岩棉系统在现有抹面层性能状态下,系统内表面在热湿耦合的作用下,存在发霉结露的可能性。最后,本研究明确了岩棉外保温系统在热湿耦合作用下的―长期性能‖定义和内涵。长期性能的―时间特性‖具体包括评价时间周期与评价周期的频率峰值,通过时域分析将长期性能中的时间效应问题简化为双向温湿传递状态下的年度周期的循环次数,并采用频域分析的方法,在循环周期的基础上考虑频率的影响,给出了评价的时间周期与温湿负荷频率峰值确定方法。长期性能的性能指标归纳为三类:热工性能累积效应、安全性能累积效应和耐久性能累积效应。研究分析了系统长期性能的变化规律,提出了热工性能累积效应评价因子(2、安全性能累积效应评价因子(2、耐久性能累积效应评价因子(2来定量评价岩棉统整体性能随着时间的推移逐渐变化的程度。最终,研究建立热湿耦合作用下岩棉外保温系统长期性能的综合评价指标W_Lp,并明确了其计算方法。研究结合实验室定量化试验,给出了热湿耦合对外保温系统热工性能和系统强度的影响,并开创性的引入了热湿强度保留率和不可逆比的概念分析系统的强度,提出了裂缝的限制要求,将系统抹面层的热湿应力视为平面应力问题并给出了计算方法等,深入发掘了系统性能与热湿耦合的内在机理关系,为后续的研究做了有益的尝试。更多还原

【Abstract】 With the increasing requirement for the fire performance of ETICS in China,stone wool ETICS is used more and more as a Class A fire performance system.Most of the previous researches are focused on material properties.Few researches are based on quantitative analysis of stone wool ETICS.Therefore,these studies are unable to establish the relationship between long-term performance of and hygrothermal distribution of stone wool ETICS.In view of the application and development of stone wool ETICS,it was summarized into three basic structural forms.Based on the characteristics and requirements of coupled heat and mass transfer,three basic structural forms of stone wool ETICS are condensed into one simplified structural model suitable for coupled heat and mass transfer.The simplified construction model provides a practical basis for the hygrothermal analysis and establishes a reliable relationship between theoretical analysis and engineering application.This research takes the typical stone wool ETICS construction in China as test research object.Comprehensive tests of concrete and stone wool,EPS,adhesives,render coating were done in this research for the first time,which including the basic physical properties,thermal physical properties and mositure physical propertie.Especially,the water absorption coefficient,liquid water diffusion coefficient and specific heat tests for the adhesive and render coating fill the gaps in the domestic related research.In the test and analysis of thermal conductivity,the error of the test system is studied,the method of correcting contact thermal resistance is proposed,and the coupling effects of temperature and moisture on thermal conductivity of building materials can be simplified to the 2-variable linear function.This research choose stone wool ETICS as a whole object and establish coupled heat with moisture transport equation.According to the characteristics of the stone wool ETICS and porous media,simplified assumptions was set for coupled heat with moisture transport physical model.Based on the continuity principle of heat and moisture transfer,the balance equation of stone wool ETICS is given for the first time,which take the temperature and relative humidity as driving potential.This method is simple in form and easy to understand and calculate.Simulations of stone wool ETICS were done under different conditions to analyze the moisture content in each layer of the system.An important issue to be solved currently is how to propose reasonable indicators for water vapour and liquid water transfer performance in stone wool ETICS in different climate zones in China.Simulations of different render coating performances were also done to analyze the moisture content in each layer.―unsteady-state liquid water – water vapour model‖ is more close to the actual situation.The effects of rainfall of stone wool ETICS are far greater than the influence of air relative humidity.The moisture content of thermal insulation layer in ETICS is also affected by the water vapour diffusion resistance of wall.Based on these,indicators for water vapour and liquid water were proposed,which provides a foundation for the stone wool ETICS standards in China.Finally,the definition and connotation of the "Long-Term Performance(LTP)" of the stone wool ETICS under the hygrothermal action is proposed in this study.This method simplifies the Long-Term effect to a periodic cycle which include two-way HAM transfer.The method for determining the peak value of temperature and humidity load is given by taking into account the influence of frequency domain on the basis of periodic cycle.The change rule of LTP of the stone wool ETICS is analyzed.This paper puts forward the evaluation factor of thermal performance cumulative effect(),the evaluation factor of the safety performance cumulative effect()and the evaluation factor of the durability cumulative effect().These factors can be used to quantify the degree of changes in the overall performance of stone wool ETICS as time changes.The comprehensive evaluation index for the long-term performance(WLp)of stone wool ETICS under the hygrothermal action is proposed and its calculation method is made clear.更多还原