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为探明日光温室墙体层间温度变化及热量传递动态规律,采用有限差分法建立墙体一维非稳态导热模型,利用MATLAB编制相应的模拟程序,计算出日光温室墙体各点的温度和热流。结果表明:该模型能够比较准确模拟日光温室土墙的温度。墙体内侧存在有效蓄热层,它对日光温室室内热环境有积极的作用。墙体有效蓄热层的热流白天指向墙体外侧,夜间指向墙体内侧,因此它的厚度直接根据热流的方向确定。有效蓄热层与天气、墙体总厚度以及墙体热特性参数有关。2012-12—2013-01期间有效蓄热层厚度为0.26~0.45m不等,最大值出现在连续雪天。同时从理论上验证了3.0m厚的温室土墙内部存在热流相对稳定的“热稳定层”。
In order to find out the temperature change and the heat transfer rule of sunlight greenhouse wall, a one-dimensional unsteady thermal model of the wall was established by finite difference method. The corresponding simulation program was compiled by MATLAB to calculate the temperature of each point in the solar greenhouse wall And heat flow. The results show that this model can simulate the temperature of soil wall in solar greenhouse more accurately. There is an effective heat storage inside the wall, which has a positive effect on the indoor thermal environment of the solar greenhouse. The heat flow from the effective thermal storage layer of the wall points to the outside of the wall during the day and to the inside of the wall at night, so its thickness is directly determined by the direction of heat flow. The effective thermal storage layer depends on the weather, the total thickness of the wall, and the wall thermal parameters. During 2012-12-2013-01, the effective heat storage layer thickness ranged from 0.26 to 0.45m, with the maximum occurring in continuous snow days. At the same time, it is verified theoretically that there is a relatively stable “heat stabilized layer” of heat flow inside the 3.0 m thick greenhouse soil wall.