日光温室夜间空气自然对流边界层的确定及量化分析  

Determination and Quantitative Analysis of Natural Convection Boundary Layer of Air in Solar Greenhouse

作　　者：张传坤 魏珉[2] 徐平丽[3] 杨宁 刘波 王晓 孔祥华 Zhang Chuankun;Wei Min;Xu Pingli;Yang Ning;Liu Bo;Wang Xiao;Kong Xianghua(Institute of Vegetables and Flowers,Shandong Academy of Agricultural Sciences,Jinan 250100,China;HorticultureScience and Engineering College,Shandong Agricultural University,Taian 271018,China;Bio-Tech Research Center,Shandong Academy of Agricultural Sciences,Jinan 250100,China)

机构地区：[1]山东省农业科学院蔬菜花卉研究所,山东济南250100 [2]山东农业大学园艺科学与工程学院,山东泰安271018 [3]山东省农业科学院生物技术研究中心,山东济南250100

出　　处：《山东农业科学》2020年第5期31-38,共8页Shandong Agricultural Sciences

基　　金：山东省农业重大应用技术创新课题(鲁财农指〔2015〕16)。

摘　　要：为研究塑料薄膜覆盖日光温室夜间的保温原理,运用自然对流边界层理论对日光温室夜间垂直方向上的温差分布进行研究。结果表明:①试验温室地面以上0.10 m内、薄膜内侧0.10 m内温差积分占垂直方向上总温差积分的比例分别为45.55%、34.54%;地面以上0.10 m处与薄膜内侧0.10 m处之间的距离为4.98 m,其温差积分占总温差积分的比例为19.91%。②试验温室地面和薄膜内侧存在速度边界层,夜间速度边界层瑞利数(Ra)为1.66×10^10~3.50×10^10,为湍流边界层。③日光温室除去受到覆盖物的保温因素外,内部空气自然对流也产生层流底层,增大了传热热阻,从而实现保温作用。④多膜覆盖、双层膜、内保温等栽培设施将空气分割成不同的空间,空气在不同的空间内分别进行自然对流,在增加的膜的两侧分别产生层流底层,保温效果优于单层膜保温效果,但保温效果的增幅随膜层数增加而降低。⑤试验期间温室地面、薄膜内侧湍流边界层厚度范围为0.13~0.14 m、层流底层厚度范围为5.01×10^-3~5.90×10^-3 m,薄膜内侧层流底层对温室的保温作用为0.70~1.49℃。In order to study the heat preservation principle of plastic film at night,the temperature difference distribution in the vertical direction of solar greenhouse was studied with the theory of natural convection boundary layer as research foundation.The results were as follows.①The proportion of temperature difference integral within 0.1 m above the ground and within 0.1 m under the plastic film was 45.55%and 34.54%respectively to the total temperature difference integral in the vertical direction.The distance from 0.1 m above the ground to 0.1 m under the film was 4.98 m,and the proportion of the temperature difference integral to the total temperature difference integral was 19.91%.②There was a flow boundary layer close to the ground and the inside of film.The Rayleigh number(Ra)of the velocity boundary layer of the experimental greenhouse was calculated to be 1.66×10^10~3.50×10^10,which indicated that the velocity boundary layer was a turbulent boundary layer.③In addition to the heat preservation caused by preservation quilt,the night heat preservation of the plastic film was realized by natural convection of the internal air to form a laminar flow bottom layer,which increased the heat transfer thermal resistance.④The cultivation facilities such as multi-film mulching,double-layer film and internal heat preservation divided the air into different spaces,and the air flows naturally in different spaces.The laminar bottom layers produced on both sides of the increased film,so the heat preservation effect was better than that of single-layer film.But the increase of temperature preservation declined with the increase of film layers.⑤The thickness of the turbulent boundary layer above the ground and under the film during the test was 0.13~0.14 m in the tested greenhouse,and that of the laminar flow bottom layer was 5.01×10^-3~5.90×10^-3 m.The heat preservation effect of the laminar bottom layer under the film was 0.70~1.49℃during the experiment.

关 键 词：日光温室 塑料薄膜 自然对流 边界层 湍流边界层 层流底层 

分 类 号：S625.1[农业科学—园艺学]