摘要
城市下垫面材料对城市微气候的营造至关重要,针对加气砼和多孔外墙砖这两种典型的城市下垫面材料,在风洞模拟广州夏季典型气象日环境下,同时对干燥和湿润试件隔热特性展开研究,结果表明:从对室外环境的影响方面,湿润多孔砖及较大厚度的加气砼外表面温度较低,不会成为局地小气候的负担,有利于营造凉爽舒适的室外热环境;从材料隔热方面评价,加气砼优于多孔外墙砖,并且进一步发现,多孔材料的隔热特性与孔隙特性、材料厚度及含水率均有直接关系,并非湿润试件的隔热效果都优于等厚的干燥试件,虽然材料增厚,隔热效力整体提升,但表层蒸干将导致被动蒸发极大削弱,在内部水分蓄热对表面温度的反作用下,大厚度湿润试件的表面温度将超过等厚的干燥试件,因此,若要被动蒸发的强大优势维稳,加气砼和多孔砖的补水时间间隔分别不能超过24 h和72 h。
The urban underlying surface materials are critical for the creation of urban microclimate.Take aerated concrete and porous exterior wall brick as research object,using wind tunnel to simulate Guangzhou summer typical meteorological environment,the thermal insulation properties of the two materials under drying and wetting conditions were studied.The result shows:from the impact on the outdoor environment,wet porous brick and aerated concrete of larger thickness have lower surface temperature,and will be beneficial to create a cool and comfortable outdoor thermal environment;from the thermal insulation of materials,aerated concrete is superior to porous exterior wall brick,and further found that the heat insulation characteristics of porous materials are directly related to pore characteristics,material thickness and water content,therefore,it can not be generalized that the insulation effectiveness of the wet material is better than that of the drying one,although thermal insulation effect enhancing with the thickness increase,less and less surface moisture will lead to a great decrease in passive evaporation,then,under the reaction of the internal moisture heat storage to surface temperature,the temperature of large thickness wetted specimen will exceed the same thickness of the dry one.so,if we want the passive evaporation advantage maintain powerful and stability,water replenishment interval of aerated concrete and porous brick shall not exceed 24h and 72h respectively.
作者
李宁
许伊那
廖利娣
LI Ning;XU Yina;LIAO Lidi(School of Architecture,Henan University of Science and Technology,Luoyang 471023,Henan;Architectural design and Research Institute,South China University of Technology,Guangzhou 510540,Guangdong;GuangDong Building Material Research litstitute ,GuangZhou510160,GuangDong,China)
出处
《建筑科学》
CSCD
北大核心
2018年第12期26-31,156,共7页
Building Science
基金
国家自然科学基金项目“基于动态实验气候的建筑材料表面换热问题研究”(51208182).
关键词
被动蒸发
隔热
多孔建筑材料
热湿气候风洞
passive evaporation
heat insulation
porous building materials
hot-humid climatic wind tunnel
