建筑多孔饰面砖动态蒸发过程的风洞实验研究

发布时间：2018-04-13 22:16

本文选题：多孔材料 + 蒸发降温　；参考：《华南理工大学》2013年硕士论文

【摘要】：被动蒸发冷却技术是自然调和理论的发展与应用。在建筑外表面敷贴含湿的多孔材料实现蒸发降温，使自然资源得以转换和重构，不仅能有效降低建筑能耗，还能改变城市下垫面的性质，从而改善城市热环境。对于钢筋混凝土等重型围护结构，在其外表面敷贴多孔材料，进行蓄水蒸发降温，提高重型围护结构的隔热性能，具有重要的实际价值。然而在南方高温高湿的气候条件下，多孔材料的蒸发能力一直受到质疑。对于含湿多孔材料的热工性能参数，一般是在其的含水率不断变化的情况下获得的。由于不能对多孔材料的含水率进行控制，缺乏稳定的实验条件，所得到的热工参数受外界条件的影响较大，准确度受到质疑。本文针对上述问题，对热湿气候风洞实验台进行了改造，增加了补水装置，实现了对实验试件含水率的控制，为研究多孔材料的动态蒸发过程提供了实验基础。同时，本文建立了与重型围护结构外表面敷贴多孔饰面砖进行蒸发降温过程相呼应的，重型实验试件的风洞实验方法。在此基础上，进行了大量的风洞实验，得到了含湿多孔材料的一系列热工性能参数。本文的主要成果如下：（1）通过对热湿气候风洞的研究，设计并建立了一套切实可行的补水装置，可实现对实验试件的持续补水。（2）对含湿多孔材料的热湿气候风洞实验方法进行研究，建立了适用于重型实验试件动态蒸发过程的蒸发量测量方法。（3）通过风洞实验，获得了持续补水工况下重型实验试件的逐时蒸发量，并与室外气象参数进行了偏相关分析，得出了利用含湿多孔材料实现建筑围护结构的蒸发降温技术，在广州地区气候条件下的适用性。（4）分析实验试件的表面温度和热流变化，得到含湿多孔饰面砖的蒸发降温效果。（5）利用热流计法计算实验试件的平均热阻，通过定义求得多孔饰面砖层的平均蓄热系数；利用热工计算方法和根据实测的延迟时间反算平均热阻的方法，对实验结果进行了验证，求得实验误差。（6）根据试件外表面的热平衡关系，，对实验试件外表面的换热特征进行分析，并求得实验试件的太阳辐射吸收率和外表面的总换热系数。
[Abstract]:Passive evaporative cooling technology is the development and application of natural harmonic theory.The application of wet porous materials on the outer surface of buildings can reduce the temperature of evaporation, transform and reconstruct the natural resources, not only reduce the building energy consumption effectively, but also change the properties of the underlying surface of the city, thus improving the urban thermal environment.For heavy-duty enclosing structures such as reinforced concrete, it is of great practical value to lay porous materials on its outer surface, to store water, evaporate and cool down, and to improve the heat insulation performance of heavy-duty enclosing structures.However, the evaporation ability of porous materials has been questioned in the southern climate of high temperature and high humidity.The thermal performance parameters of wet porous materials are generally obtained under the condition of constant change of moisture content.Because the moisture content of porous materials can not be controlled and the experimental conditions are not stable, the thermal parameters obtained are greatly affected by the external conditions and the accuracy is questioned.In order to solve the above problems, the experimental bench of wind tunnel in heat and wet climate has been reformed in this paper, and the water supply device has been added to control the moisture content of the experimental specimen, which provides the experimental basis for studying the dynamic evaporation process of porous materials.At the same time, a wind tunnel experiment method for heavy duty experimental specimens is established, which is consistent with the evaporation and cooling process of heavy duty envelope structures with porous veneer brick attached to the outer surface.On this basis, a large number of wind tunnel experiments have been carried out, and a series of thermal performance parameters of wet porous materials have been obtained.The main results of this paper are as follows:1) through the study of the wind tunnel in hot and wet climate, a set of feasible water supply device is designed and established, which can realize the continuous water supply to the experimental specimen.2) the wind tunnel experimental method of wet and thermal climate for porous materials is studied, and the evaporation measurement method suitable for the dynamic evaporation process of heavy-duty experimental specimens is established.3) through wind tunnel experiment, the hourly evaporation of heavy-duty experimental specimens under the condition of continuous water supply is obtained, and the partial correlation analysis with outdoor meteorological parameters is carried out, and the evaporative cooling technology of building enclosure structure is obtained by using wet porous materials.Applicability under climatic conditions in Guangzhou.(4) the surface temperature and heat flux of the specimens are analyzed, and the evaporative cooling effect of the wet porous decorative brick is obtained.5) the average thermal resistance of the experimental specimen is calculated by using the heat flow meter method, and the average heat storage coefficient of the porous ornament brick layer is obtained by definition, and the thermal calculation method and the method of inverse calculating the average thermal resistance based on the measured delay time are used.The experimental results are verified and the experimental errors are obtained.6) according to the heat balance relationship of the outer surface of the specimen, the heat transfer characteristics of the outer surface of the specimen are analyzed, and the solar radiation absorption rate and the total heat transfer coefficient of the outer surface of the experimental specimen are obtained.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU522.18

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