外保温墙体传湿试验及模拟研究

发布时间：2018-01-26 04:42

本文关键词： 水分迁移外保温墙体 CHAMPS模拟含湿状态传热系数　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：对于严寒地区而言，围护结构保温性能的优劣直接影响到建筑能耗的高低。而墙体材料的含湿状况对围护结构的热工性能有着重要的影响，水分在墙体内部积聚还会对结构的耐久性和舒适性产生负面影响。因此，，墙体内部水分迁移过程的研究对建筑节能设计和评估具有重要意义。本文以研究EPS薄抹灰外保温墙体内部的水分迁移过程为核心，通过对EPS板的热湿性能测试和外保温墙体试件的稳态传湿试验，以及哈尔滨地区外保温墙体热湿状况模拟和实际测试结果的对比分析，得出墙体内部的水分迁移规律。首先采用加热蒸汽加湿和水中浸泡使EPS板吸湿后测试其导热系数，得出EPS板体积含湿率对其导热系数的影响规律。对稳态导热系数测试过程进行CHAMPS模拟后发现，测试过程中试件内部的水分分布发生了较大的变化，因此稳态法不宜用于含湿试件导热系数的测试。然后基于冰柜和加湿器构造的温湿度场，进行了外保温墙体试件的稳态传湿试验。两组试件的热端温度为室温，热端相对湿度分别99%RH和70%RH；冷端均由冰柜控制。试件受到所处温湿度梯度作用和混凝土的自干燥作用，内部湿度场重新分布。试件中混凝土层靠近热端部分的相对湿度均有所增大，远离热端部分均降低，其中，热端环境湿度较高的试件由于所处湿度梯度更大，其内部的湿度变化幅度也更大；试验结束时，基层与苯板界面的空气层处相对湿度均持续减小。模拟结果与测试结果吻合较好。对哈尔滨地区初始含湿饱和的EPS外保温墙体竣工后含湿状况的模拟结果表明，工程竣工四五年后墙体材料的体积含湿率基本达到稳定状态，而相对湿度受到外界环境的影响，较难达到稳定状态；竣工后第一年墙体内部空气层结露的可能性较大；竣工第三年后墙体传热系数受材料含湿状况的影响极小。最后对EPS外保温剪力墙内部的含湿状态进行监测分析，结果表明，竣工初期墙体内混凝土层的相对湿度较高，由于所处环境相对湿度较低，混凝土层的相对湿度呈快速下降趋势。竣工两年后，室内外环境成为墙体内部湿度状态的主要影响因素，建设期引入墙体的水分大部分已蒸发完毕。实际墙体测试结果与模拟结果之间存在较大差异，其原因主要是二者边界条件差异较大，实测墙体的环境相对湿度远低于模拟软件所用值，且实际墙体含湿状态的影响因素更多。尽管如此，模拟结果仍具有参考价值。
[Abstract]:In cold areas, building envelope insulation performance will directly affect the level of building energy consumption. And the wall material moisture condition has an important effect on the thermal performance of the retaining structure, the water inside the wall will accumulate on the durability of structure and comfort have a negative impact. Therefore, study on the internal wall of water transfer process is of great significance to the construction of energy-efficient design and evaluation.
Based on the research of EPS thin plastering exterior insulation wall inside the water transfer process as the core, through the EPS board thermal insulation performance test and external wall specimens steady-state moisture transfer test, comparative analysis of wall thermal and humidity condition simulation and actual test results, the Harbin area outside the insulation, the rule of the internal wall of the water transfer.
The heating steam humidification and water immersion EPS plate after moisture conductivity test, the influence of wet rate on the thermal conductivity of EPS containing plate volume. CHAMPS simulation of steady state thermal conductivity testing process and found that the distribution of the water change test process, so it should not be steady for wet specimens of thermal conductivity test.
Then based on the temperature and humidity field freezer and humidifier structure, the external insulation wall specimen steady-state moisture transfer test. The hot end temperature of two groups of specimens at room temperature, the hot end of relative humidity were 99%RH and 70%RH; the cold end is freezer control. Try to have the effect of drying temperature and humidity gradient. The concrete internal humidity field, re distribution. Try to increase the concrete layer close to the hot end part of the relative humidity are in far away from the hot end part decreased, the high humidity hot end environment specimens because of the humidity gradient is larger, the internal humidity change rate is higher; test at the end of the air layer at the base and interface of the benzene plate relative humidity decreasing. The simulation results agree well with the experimental results.
In Harbin area, initial moisture saturated EPS external insulation wall after the completion of the moisture condition of the simulation results show that the project is completed after four or five years of wall material volume humidity rate reaches a steady state, while the relative humidity is affected by the outside environment, more difficult to reach a steady state; after the completion of the first year of internal air layer wall condensation the possibility of a larger; third years after the completion of the heat transfer coefficient of wall material has little effect on moisture conditions.
At the end of the EPS external insulation shear wall internal moisture monitoring and analysis, the results show that the completion of the initial state, the relative humidity is high in the wall of the concrete layer, due to the low relative humidity environment, relative humidity of concrete layer decreased rapidly. Two years after completion, indoor and outdoor environment become the main factors influencing the internal humidity condition of the wall the introduction of the water wall construction period has been most evaporates. There is a big difference between the actual wall test results with simulation results, the main reason is the large differences between the two boundary conditions, the measured wall environment relative humidity is far lower than the simulation software used by value, and the actual effect of the wall moisture conditions more. Nevertheless, the simulation results still have reference value.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU111.41

【参考文献】