【作者】 韩亚东；

【导师】 李天来；

【作者基本信息】 沈阳农业大学 ， 设施园艺学， 2015， 博士

【摘要】 日光温室围护结构由三面墙体和顶部前、后屋面组成,只有前屋面为可透光部分。日光温室可在不加热、少量加热的情况下实现蔬菜的越冬生产,不仅促进农民增收、解决蔬菜周年供应问题,也提高了冬、春季节的光能资源的高效利用。据统计,至2013年我国日光温室面积达90万hm2,已成为部分地区的支柱产业,日光温室不仅在我国北方地区得到广泛应用,一些发达国家如日本、加拿大等国也引进了部分日光温室,并开展相关研究。到目前为止,日光温室(第3代节能型日光温室)可在-28℃以上地区实现冬季不加温正常生产果菜,而具有现代化的水循环蓄热彩钢板保温装配式节能日光温室将来可在-30℃地区实现不加温情况下正常生产喜温蔬菜,日光温室也必将受到众多国家和地区的重视。目前大多数的日光温室环境调控能力还较差,受围护结构的影响,日光温室内的气象要素分布特征独特,但有关日光温室内能量收支状况及分配研究尚不够深入。因此,本文把日光温室围护结构内表面、土壤表面和室内空气组成“面-气”系统,从“面-气”系统能量平衡出发,把“面-气”系统净能量定义为太阳净辐射与围护结构和土壤热通量之差,净能量与“焓值变化量”、热风炉加温筒壁与空气自然对流换热量、上通风口通风换热量和冷凝释放热量组成“面-气”系统能量平衡方程。本文构建了“面-气”系统能量平衡方程中几个主要分量模型及其变化规律,文中还分析了日光温室内几个气象要素的分布特征,以期为提高日光温室环境控制能力提供一定的理论参考。主要研究结果如下：1.构建了日光温室的“可蔽视角”模型,按照这一模型可计算出不同季节不同时刻日光温室内的直接辐射照射区域,并可计算出直接辐射量。并通过等分以该点为中心的水平面,对每一等分垂直面上的非“可蔽视角”进行累积后求均值,从而求算出散射辐射量。经过室内散射辐射和总辐射模拟值和实测值的拟合验证,模拟值与实测值拟合度显著,说明可以用该模型进行日光温室内光辐射量模拟,但在本试验中模拟值略高于实测值,平均偏高6%-9%。2.构建了采光屋面南北方向倾角同时叠加压膜线造成的东西倾角后的“采光屋面太阳高度角”计算模型。结果表明日光温室采光屋面由压膜线造成的东、西倾角改变了采光屋面的坡度、坡向,进而改变了“采光屋面太阳高度角”。上午棚面东倾的部分可增加“采光屋面太阳高度角”,并在10点前可增加采光屋面的透光率；“采光屋面太阳高度角”与实测采光屋面透光率呈对数曲线关系,当采光屋面太阳高度角大于45°时,透光率变化趋缓,约为75%+10%。3.构建了传热筒外壁温度与距炉体距离的关系模型,结果表明传热筒外壁温度与距炉体的距离呈斜率不等的线性递减规律,即炉体附近传热筒壁温越高,递减斜率越大。筒外壁与空气间的自然对流换热量与距炉体距离总体呈斜率不等的线性递减规律。4.构建了以日光温室内温、湿度为已知条件的湿空气湿焓计算模型。“焓值变化量”的变化规律表现为除春季夜间为负值外,冬季白天、夜间和春季白天焓值变化量都在零值附近波动。冬季无论是夜间还是白天,潜热量明显大于显热量。春季夜间潜热量明显大于显热量,白天相反。5.构建了基于能量平衡的日光温室揭帘时间模型,该模型可确定不同季节的揭帘位置理论上最早揭帘时间,即以室内收到的净辐射量等于不揭帘时日光温室棚面的损失能量作为最早揭帘时间。揭帘时间主要和揭帘时的太阳辐射及室内外温差有关,当温差确定时主要和到达室内的太阳辐射量有关。按照这一模型对比了两种揭帘方式的揭帘时间,结果表明,沈阳地区日出后日光温室内收到的能量超过不揭帘时,采用先揭到日光温室的2.5m高处停留20min左右、再揭到日光温室3.4m高处的方式,比直接揭到日光温室3.4m高处可理论上提早揭帘20min。6.明确了冬季夜间日光温室内的净能量值为负值,白天部分时间为正值；春季夜间和白天日光温室内的净能量都为正值。冬、春夜间日光温室北墙和后坡热量流向室内空气的值较小,棚膜向外放出能量较大,因此日光温室内冬季夜间为降温；冬、春白天流向北墙和后坡的热通量均较小,冬季白天流向棚膜的热通量最大,而春季白天流向土壤热通量最大。7.明确冬、春采用上通风口通风时,通风换热量中排风能量大于进风能量；通过采用CFD方法对日光温室内空气风速和风向状况进行仿真模拟,结果为上通风口为进风口时,气流进入日光温室后向下俯冲,到达温室底部后分为2股,并形成2个涡旋。实测日光温室内剖面上的风速分布状况为进风口附近相对风速最大,越往下风速越小冠层内相对风速最小。8.在冬季夜间热风炉加温时,冬季日光温室内不同剖面气温分布特征为热风炉所在一侧的气温明显高于远离热风炉一侧的气温,东西不同剖面温差最大可达3-4℃；在同一剖面内,夜间加温时气温的分布规律呈现出上部气温高于下部气温,温差在2-5℃；冬季不加温条件下,温室内同一剖面下部空气日平均温度大于上部空气日平均温度,温差在1～2℃。9.在冬季不加温条件下,日光温室内日平均相对湿度剖面分布规律为上部大于中下部,南侧区域大于北侧区域,同一剖面内相对湿度差在5～10%。更多还原

【Abstract】 Solar greenhouse is surrounded by roof and walls on three sides,The roof is composed by north slope and lighting roof,vegetable production is normal in no heating or a little heating conditions in winter, and it not only to promote the increase of farmer’s income, to solve the problem of supply of vegetable, but also improve the efficient use of the solar energy in winter and in spring.According to statistics,the area of China’s greenhouse up to 900,000 hm2 till 2013,and it has become a pillar industry in some areas.Solar greenhouse not only widely used in domestic northern area but also introduced to some developed countries such as Japan,Canada and carried out related research. The third generation energy-saving solar greenhouse can realize the normal production of vegetables in areas without heating with the winter’s minmum temperature above-28 ℃ so far.Color plate assembled heat Preservation greenhouse by water cycle is modern thermal storage greenhouse,it will be achieved normal production of vegetables in areas without heating with the winter’s minmum temperature above-30℃ in the future, the greenhouse will has more attention in the world. At present, the ability of environment control in most of solar greenhouse is poor, affected by the enclosure structure, the distribution research of meteorological elements in solar greenhouse is less and the research about energy budget allocation in greenhouse is not enough.Therefore, The’boundary-air’system is make up by envelope surface, soil surface and indoor air and total energy balance equation of’boundary-air’system is constructed in this article.The net energy (B) is defined as the difference of net solar radiation and envelope and soil heat fluxdifference.A new energy balance equation is composed by energy of B, enthalpy variation,heating, ventilation heat loss and condensation heat.This article construct main components model of energy balance equation, and also analyses meteorological elements distribution in order to provide a theoretical reference for improving the ability of environment control in solar greenhouse.The results are as follows:l.The shadowing effect of solar greenhouse enclosure structure on solar radiation was analyzed, the’preventing-view’s angle’of any points within solar greenhouse were calculated by using main parameters of solar greenhouse and solar azimuth. Any point which could be obtained direct solar radiation if the’preventing-view’s angle’is smaller than solar altitude. A hypothesis is that any point obtains isotropic diffuse solar radiation form the sky, diffuse solar radiation was calculated by accumulating the’non-preventing-view’s angle’.Based on these analyses, the direct solar radiation, diffuse radiation and total solar radiation at any points within solar greenhouse in sunny days were estimated.The estimated values at certain point within solar greenhouse were compared with measured values at that point, which were measured within LiaoShenⅡ type solar greenhouse, the estimated values were higher than measured values by about 6% and 9% respectively for scatter radiation and total radiation.2.Film line formed eastward or westward dip add southward dip can effect’solar altitude angle on the film’and make a complex lighting distribution in solar greenhouse.The’solar altitude angle on the film’is calculated in this paper. It shows that westward or eastward dip changed the slope, slope-exposure and solar elevation of film. Eastward dip can increase the solar elevation of righting film and increase the transmittance before 10:00am. The transmittance adheres to Logarithmic curve with’solar altitude angle on the film’, the transmittance remained a stable value at 75% ± 10% when’solar altitude angle on the film’is bigger than 45°.3.According to the heat transfer principle, the heat change between cylinder ektexine of hot-blast stove and space air were simulated for understanding the heat distribution principle during hot-blast stove heating time in greenhouse. It showed that the cylinder ektexine temperature and the exchange between cylinder ektexine of hot-blast stove and space air decreasing with unequal slope with the distance to the hot-blast stove.4.Approximate calculation method of wet enthalpy is derived by temperature and humidity in solar greenhouse. Latent heat is significantly larger than sensible heat either at nightime or daytime in winter. in spring,the same regular at nightime,but on the contrary at daytime; The value of enthalpy is fluctuated around zero at daytime and nightime in winter and at daytime in spring, but negative at nighttime in spring.5.Based energy balance the time and location model of uncovering the curtain are constructed. The earlist uncovering time is when the radiation received is the same as lossed on the cover matials. The exposing time is mainly related to the radiation and the temperature difference of inside and outside, and the time is determined by the amount of solar radiation reaching the indoor when the temperature difference is stable. Shenyang eara can be exposed to 2.5 meters first and then open up to 3.4 meters is 20min earlier than direct expose to 3.4m after sunrise.6.The value of net energy B is negative in winter night amd partial is positive during daytime; net energy value is positive during the nightime and daytime in winter and spring; The heat flux flow to the north wall and slope is smaller than greenhouse film during night in winter and spring; The heat flux flow to the film is largest in winter and flow to the soil in spring during daytime.7.The up vent is opened in winter and spring the theoretic energy balance equation of up vent ventilation is studied and wind speed is measured.lt shows that the upward vertical wind frequency is greater than the downward,and the energy to the outside is greater than from outside. By using CFD method,the wind speed and wind directions are simulated, the flow enters the greenhouse form up vent, arrive at the bottom of the greenhouse and divided into 2 two vortices.The maximum relative wind speed is near the up vent, the minimum of wind speed is in the canopy.8.At night-time in winter,the air temperature of the side which was near the hot-blast stove was higher obviously than that in the other side, air temperature at upside was higher than that at bottom in the same section.The difference of temperature between five sections is about 3 ℃-4℃,and the difference is about 2℃-5 ℃ in the same section. But on the conditions of none heating,the difference of temperature is 1℃-2 ℃ in the same section.9. The largest humidity is at upper part and 5%～10% in different part in the same section更多还原