摘要
In order to provide theoretical basis and data support for improving the production mode of covering,this study investigated the nighttime air temperature formed by multiple layers of films with tunnel sheds and small tunnel sheds as trial subjects.The experiment was carried out in four tunnel sheds with 0 or 2 small tunnel sheds covered by 0,1,2 and 3 layers of films,respectively in Jinan,Shandong Province in winter of 2018.The nighttime air temperatures of tunnel sheds and small tunnel sheds formed by 1,2,3 and 4 layers of plastic film were measured and analyzed to simulate the temperature environment of early-spring season.The results showed that there were little differences between the nighttime air temperatures inside the tunnel sheds which was installed 0-3-layer small tunnel sheds inside,and there were uncertainty in the values of the air temperatures inside and outside the tunnel sheds;and the nighttime temperature conditions were constantly improved with the number of plastic film layers increasing under the conditions of this study.The analysis indicated that the mechanism of raising the temperature surrounded by plastic film was not only due to its own thermal parameter (thermal conductivity).MATLAB fitting analysis results showed that the increment of nighttime temperature in multi-film coverings became smaller with the number of film layers increasing.In this study,the number of layers in multi-film covering should not exceed 5 layers.
In order to provide theoretical basis and data support for improving the production mode of covering, this study investigated the nighttime air temperature formed by multiple layers of films with tunnel sheds and small tunnel sheds as trial subjects. The experiment was carried out in four tunnel sheds with 0 or 2 small tunnel sheds covered by 0, 1, 2 and 3 layers of films, respectively in Jinan, Shandong Province in winter of 2018. The nighttime air temperatures of tunnel sheds and small tunnel sheds formed by 1, 2, 3 and 4 layers of plastic film were measured and analyzed to simulate the temperature environment of early-spring season. The results showed that there were little differences between the nighttime air temperatures inside the tunnel sheds which was installed 0-3-layer small tunnel sheds inside, and there were uncertainty in the values of the air temperatures inside and outside the tunnel sheds; and the nighttime temperature conditions were constantly improved with the number of plastic film layers increasing under the conditions of this study. The analysis indicated that the mechanism of raising the temperature surrounded by plastic film was not only due to its own thermal parameter(thermal conductivity). MATLAB fitting analysis results showed that the increment of nighttime temperature in multi-film coverings became smaller with the number of film layers increasing. In this study, the number of layers in multi-film covering should not exceed 5 layers.
基金
Supported by Weifang Comprehensive Experimental Station Project of National Watermelon and Melon Industrial Technology System(CARS-25)
Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2018D05)
