陶粒湿屋面热湿过程分析研究
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摘要
屋面作为建筑物与大自然的主要交汇面,是太阳光和热的主要承受面,也是降水的主要承受面。陶粒湿屋面是根据湿屋面的隔热机理,在屋面上铺设一层陶粒,利用陶粒在降水时蓄水,存在太阳辐射和室外空气换热时,材料层中的水分逐渐迁移至材料层的表面蒸发,带走大量的汽化潜热,来有效地遏制太阳辐射或大气高温对屋面的不利作用,改善屋面温湿度的分布状况、延长防水层的使用寿命、减缓城市排泄雨水系统的压力,使建筑更有效地与自然和谐。
本文从几种被动蒸发隔热屋面的隔热理论分析入手,对陶粒湿屋面的热湿传递过程进行了详细地理论分析,将湿度对温度的影响简化为陶粒层的当量导温系数α_2随陶粒层平均含水率的变化,然后根据屋面的传热过程,分别建立了陶粒湿屋面和普通屋面的传热控制方程和相应的边界条件。并用有限差分法对控制方程和边界条件进行了离散。
陶粒湿屋面的热湿传递是一个多种机理综合作用下的相互耦合过程,要全面、准确地对其进行描述非常复杂。因此,建立了两个试验房和两个对比房,在2007年7月23日至8月5日期间进行了实地测试,并对测试结果进行了整理分析。结果表明:①铺设了陶粒的试验房室内空气温度在任何天气下基本都低于普通对比房室内的空气温度,日最高气温的差值最大达2℃;②试验房屋面内表面温度基本均低于相应的对比房屋面内表面温度,最大差值达3.4℃;③试验房屋面外表面综合温度与相应的对比房屋面外表面综合温度的变化基本一致,只是试验房陶粒下表面(即屋面的上表面)温度的幅度明显小于对比房的上表面温度,峰值最大差值达30.2℃,谷值最大差值达6.8℃。
最后,根据理论离散结果和室内外空气温度的测试值,应用MATLAB语言编程,模拟出两类屋面外表面综合温度和内表面温度计算值,与实测结果的对比分析,结果附和得很好。验证了陶粒湿屋面的热质迁移微分控制方程及其边界条件的数学模型和其中的各个参数的正确性,为定量研究陶粒湿屋面热湿传递过程提供了理论依据。
As the main intersection between the building and the nature,roof is also the main receiving surface of the solar radiation and the rainfall.The principle of the moist ceramic particle roof is that moist roof can be act as a heat insulator,that is to say,when it is raining,the ceramic particle stores water and when it becoming sunny the water in the material can be evaporated which will take plenty of latent heat out of the roof.This process which will keep the roof in a low temperature level can not only protect the roof from intense solar radiation and the high outdoor temperature but also can prolong the service-life of the waterproof layer.In addition,this kind of roof can also release the pressure of city's rain exhaust system in a certain extent.In a word,the moist ceramic particle roof is helpful to make the building in harmony with the nature.
Initialed from the insulation principle analysis on several passive evaporation insulation roof, this paper detailedly discussed the heat and humidity transfer process in the moist ceramic particle roof.In the analysis,the influence of the humidity to the temperature is simplified as the change of the equivalent thermal diffusivityα_2 with the average moisture content of the ceramic particle. Based on the roof's heat transfer process,the heat transfer equations and its corresponding boundary conditions of the moist ceramic particle roof and a common roof are established.The governing equation and boundary conditions are separated by the finite difference method.
The heat and humidity transfer process in the moist ceramic particle roof is a coupling process under many kinds of mechanism,and it is very complex to fully and accurately describe it.Therefore, two experimental rooms and two contrast rooms have been built to investigate this problem. Experiment are carried out during July 23 to August 5 in the year 2007 in above rooms.By the analysis of the test results,the following conclusions are obtained:①The indoor air temperature of the test room laying ceramic particle are lower than the common contrast room in any weather conditions,and the daily maximum temperature difference up to 2℃;②The inside surface temperature of the test room is basically lower than the common contrast room,and the maximum temperature difference up to 3.4℃;③The change of the outside surface synthetical temperature of the test room is basically consistent with the corresponding contrast room,besides that the ceramic surface temperature of the test room is obviously lower than the outer surface temperature of the contrast room.The maximum temperature difference of the peak time up to 30.2℃and the maximum temperature difference of the foot time up to 6.8℃.
Finally,according to the theoretical separating result and the test value of the indoor & outer air temperature,the predicted value of the outside surface synthetical temperature and the inside surface temperature about the above roofs are simulated by the MATLAB language program.The results coincide well with each other which confirmed the accuracy of the governing equations,the boundary conditions and relative parameters.This results can provide a theoretical basis for the quantitative study of the moist ceramic particle roof's heat and humidity transfer process.
本文从几种被动蒸发隔热屋面的隔热理论分析入手,对陶粒湿屋面的热湿传递过程进行了详细地理论分析,将湿度对温度的影响简化为陶粒层的当量导温系数α_2随陶粒层平均含水率的变化,然后根据屋面的传热过程,分别建立了陶粒湿屋面和普通屋面的传热控制方程和相应的边界条件。并用有限差分法对控制方程和边界条件进行了离散。
陶粒湿屋面的热湿传递是一个多种机理综合作用下的相互耦合过程,要全面、准确地对其进行描述非常复杂。因此,建立了两个试验房和两个对比房,在2007年7月23日至8月5日期间进行了实地测试,并对测试结果进行了整理分析。结果表明:①铺设了陶粒的试验房室内空气温度在任何天气下基本都低于普通对比房室内的空气温度,日最高气温的差值最大达2℃;②试验房屋面内表面温度基本均低于相应的对比房屋面内表面温度,最大差值达3.4℃;③试验房屋面外表面综合温度与相应的对比房屋面外表面综合温度的变化基本一致,只是试验房陶粒下表面(即屋面的上表面)温度的幅度明显小于对比房的上表面温度,峰值最大差值达30.2℃,谷值最大差值达6.8℃。
最后,根据理论离散结果和室内外空气温度的测试值,应用MATLAB语言编程,模拟出两类屋面外表面综合温度和内表面温度计算值,与实测结果的对比分析,结果附和得很好。验证了陶粒湿屋面的热质迁移微分控制方程及其边界条件的数学模型和其中的各个参数的正确性,为定量研究陶粒湿屋面热湿传递过程提供了理论依据。
As the main intersection between the building and the nature,roof is also the main receiving surface of the solar radiation and the rainfall.The principle of the moist ceramic particle roof is that moist roof can be act as a heat insulator,that is to say,when it is raining,the ceramic particle stores water and when it becoming sunny the water in the material can be evaporated which will take plenty of latent heat out of the roof.This process which will keep the roof in a low temperature level can not only protect the roof from intense solar radiation and the high outdoor temperature but also can prolong the service-life of the waterproof layer.In addition,this kind of roof can also release the pressure of city's rain exhaust system in a certain extent.In a word,the moist ceramic particle roof is helpful to make the building in harmony with the nature.
Initialed from the insulation principle analysis on several passive evaporation insulation roof, this paper detailedly discussed the heat and humidity transfer process in the moist ceramic particle roof.In the analysis,the influence of the humidity to the temperature is simplified as the change of the equivalent thermal diffusivityα_2 with the average moisture content of the ceramic particle. Based on the roof's heat transfer process,the heat transfer equations and its corresponding boundary conditions of the moist ceramic particle roof and a common roof are established.The governing equation and boundary conditions are separated by the finite difference method.
The heat and humidity transfer process in the moist ceramic particle roof is a coupling process under many kinds of mechanism,and it is very complex to fully and accurately describe it.Therefore, two experimental rooms and two contrast rooms have been built to investigate this problem. Experiment are carried out during July 23 to August 5 in the year 2007 in above rooms.By the analysis of the test results,the following conclusions are obtained:①The indoor air temperature of the test room laying ceramic particle are lower than the common contrast room in any weather conditions,and the daily maximum temperature difference up to 2℃;②The inside surface temperature of the test room is basically lower than the common contrast room,and the maximum temperature difference up to 3.4℃;③The change of the outside surface synthetical temperature of the test room is basically consistent with the corresponding contrast room,besides that the ceramic surface temperature of the test room is obviously lower than the outer surface temperature of the contrast room.The maximum temperature difference of the peak time up to 30.2℃and the maximum temperature difference of the foot time up to 6.8℃.
Finally,according to the theoretical separating result and the test value of the indoor & outer air temperature,the predicted value of the outside surface synthetical temperature and the inside surface temperature about the above roofs are simulated by the MATLAB language program.The results coincide well with each other which confirmed the accuracy of the governing equations,the boundary conditions and relative parameters.This results can provide a theoretical basis for the quantitative study of the moist ceramic particle roof's heat and humidity transfer process.
引文
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[9]何化岳.湿多孔材料被动防热技术研究[D].西安建筑科技大学,2006
[10]杨红霞,刘加平,刘雅君等.夏季屋顶传热过程的动态特性与顶层房间的热工设计[J].混凝土与水泥制品,2007(4):53-56
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[20]刘玉东,童明伟.蓄水屋面的传热特性动态分析[J].重庆大学学报(自然科学版),2002(8):11-13
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[22]孟庆林,陈启高,冉茂裕等.关于蒸发换热系数h_e的证明[J].太阳能学报,1999,(02):216-219
[23]孙无二,建筑材料导热系数的回归计算[J].低温建筑技术,1994,55(03):16-18
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[26]卢军,付祥钊,冯雅等.含湿多孔材料热湿迁移特性参数研究[J].重庆建筑大学学报,2000,22(4):83-86
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[28]许国仁,邹金龙,孙丽欣.污泥作为添加剂制备轻质陶粒的试验研究[J].哈尔滨工业大学学报.2007(04):557-560
[29]陈益兰,李毅,毛锡双等.页岩陶粒理化性能的研究[J].房材与应用,2000(05):3-4
[30]杨善勤.民用建筑节能设计手册[M].北京:中国建筑工业出版社,1997
[31]闫增峰.生土建筑室内热湿环境研究[D].西安建筑科技大学,2003
[32]Radhakrishna H.S.et al.,Couple heat and moisture flow through soil,J.of Geoth.Eng.,1984(10):1766-1840
[33]张宇伦,用积分有限差分法求解土壤中热量和水分的祸合流动问题[J],第三届全国岩土力学数值分析方法讨论会论文集,1988
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[37]Li Haimei(李海梅),Gu Yuanxian(顾元宪),Shen Changyu(申长雨).Finite Element Solution of Heat ransfer with Planar Phase Change by Equivalent Heat Capacity Method.Jounal of Dalian University of Technology(大连理工大学学报),2000,40(1):45-48
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[2]施建欣.我国建筑节能的必要性[J].石河子科技,2006,(03):20
[3]卢克宗.推进建筑节能,构建节约型社会[J].价值工程,2007(06):22-24
[4]刘才丰,冯雅,陈启高等.屋面蒸发隔热及应用措施[J].重庆大学学报(自然科学版),2001(03):41-44
[5]武涌.发挥政府公共管理职能,推进建筑节能建筑,2003(12):12-15
[6]解保卫,黄波.我国建筑节能发展的探讨[J].科技信息(学术研究),2007(22):263-264
[7]戴天兴.湿屋面的概念与机理[J].建筑物里专业委员会九六学术年会论文集,1996
[8]孟庆林.建筑表面被动蒸发冷却[M].广州:华南理工大学出版社,2001
[9]何化岳.湿多孔材料被动防热技术研究[D].西安建筑科技大学,2006
[10]杨红霞,刘加平,刘雅君等.夏季屋顶传热过程的动态特性与顶层房间的热工设计[J].混凝土与水泥制品,2007(4):53-56
[11]章熙民,任泽霈等编著.传热学[M].北京:中国建筑工业出版社,2001
[12]林瑞泰.多孔介质传热传质引论[M].北京:科学出版社,1995.
[13]施明恒,余莉,刘雅琴.快速干燥过程中多孔介质内部湿分迁移机理的研究[A].中国工程热物理学会传热传质学术会议论文集[C].1999.
[14]苏向辉.多层多孔结构内热湿藕合迁移特性研究[D].南京航空航天大学,2002
[15]Philip J R,de Vries D A.Moisture movement in porous material under temperature gradients.In:Trans Ami Geophys Union.1957,38(2).222-232
[16]van Arsdel WB.Appropriate diffusions calculation for falling rate phase change of drying.In:Trans AIChE.1947,36(1).13-14
[17]陈会娟,陈滨.多孔建筑材料热湿传递过程的研究[J].暖通空调,2004,(11):24-29
[18]Wyral J,Marynowicz A.Vapor condensation and moisture accumulation in porous building wall.Building and Environment,2002,37(3):313 318
[19]ChangW.J.,WengC.I.An analysis solution to coupled heat and moisture diffusion transfer in Porous materiais[J].Int.J.of Heat and Mass Transfer,2000,43:3621一3632
[20]刘玉东,童明伟.蓄水屋面的传热特性动态分析[J].重庆大学学报(自然科学版),2002(8):11-13
[21]刘加平.建筑物理(第三版)[M].北京:中国建筑工业出版社,2000
[22]孟庆林,陈启高,冉茂裕等.关于蒸发换热系数h_e的证明[J].太阳能学报,1999,(02):216-219
[23]孙无二,建筑材料导热系数的回归计算[J].低温建筑技术,1994,55(03):16-18
[24]张寅平,邱国权.蜂窝材料有效导热系数的通用计算法[J].太阳能学报,1997,18(04):349-353
[25]潘宏亮.多孔介质有效导热系数的计算方法[J].航空计算技术,2000,30(03):12-14
[26]卢军,付祥钊,冯雅等.含湿多孔材料热湿迁移特性参数研究[J].重庆建筑大学学报,2000,22(4):83-86
[27]柯劲松,刘定芳.废玻璃陶粒的开发研制[J]混凝土与水泥制品,1995(01):51-52
[28]许国仁,邹金龙,孙丽欣.污泥作为添加剂制备轻质陶粒的试验研究[J].哈尔滨工业大学学报.2007(04):557-560
[29]陈益兰,李毅,毛锡双等.页岩陶粒理化性能的研究[J].房材与应用,2000(05):3-4
[30]杨善勤.民用建筑节能设计手册[M].北京:中国建筑工业出版社,1997
[31]闫增峰.生土建筑室内热湿环境研究[D].西安建筑科技大学,2003
[32]Radhakrishna H.S.et al.,Couple heat and moisture flow through soil,J.of Geoth.Eng.,1984(10):1766-1840
[33]张宇伦,用积分有限差分法求解土壤中热量和水分的祸合流动问题[J],第三届全国岩土力学数值分析方法讨论会论文集,1988
[34]杨纯,葛新石,程曙霞等.地膜覆盖中传热问题的研究[J],工程热物理学报,1990(4):418-421
[35]李信真,车刚明,欧阳洁等编著.计算方法[M].西安:西北工业大学出版社,2000
[36]B.H.巴格斯罗夫斯基.建筑热物理学[M].北京:中国建筑工业出版社,1988
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