| 摘要: |
| 【目的】对日光温室后墙夜间的非稳态导热特性进行研究，为发挥后墙保温作用提供理论依据。【方法】在位于山东泰安的试验温室内，分别于温室后墙距地面0.1，1.1，2.1，3.1和4.1 m处及地面距离后墙0.1 m处设置测点，选取2015年越冬季某一晴天和阴天，在18：00至翌日06：00，每隔1 h测定后墙各测点的温度和热流密度，计算各测点温度变化率、热流密度积分值、后墙内部热量流动量，以及后墙与地面之间的热量流动量，研究夜间温室后墙不同高度蓄热量变化与放热量之间的关系、地面温度与后墙温度之间的关系，以及后墙内部和后墙与地面之间的热量流动。【结果】晴天夜间后墙中上部蓄热量变化基本相同且大于后墙下部蓄热量变化，后墙中上部放热量逐渐降低然后趋于平稳，后墙下部放热量逐渐增多，后墙中部放热总量最多；后墙温度24:00之前高于地面温度，24:00之后低于地面温度，后墙与地面之间存在热量流动；后墙内部热量流动数量占后墙放热总量的比值为14.2%。阴天夜间后墙中上部蓄热量变化基本相同且大于后墙下部蓄热量变化，后墙放热量从上到下逐渐增多；后墙温度低于地面温度，地面流入后墙热量占后墙放热总量的比值为3%；后墙内部热量流动数量占后墙放热总量的比值为25.5%。【结论】后墙高度、后墙不同高度蓄热量影响后墙不同高度放热量；后墙高度对放热量的影响贯穿后墙放热过程的始终，后墙蓄热量对放热量的影响主要集中在后墙放热前期；后墙热量存在自上而下的整体迁移流动。 |
| 关键词: 日光温室 温室后墙 非稳态导热 热量迁移流动 |
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| 基金项目:国家大宗蔬菜产业技术体系建设专项（CARS-25)；“十二五”国家科技支撑计划项目（2014BAD05B03）；山东省农业重大应用技术创新项目（鲁财农指（2015）16） |
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| Unsteady heat conduction characteristics of back wall of solar greenhouse at night |
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ZHANG Chuankun,WEI Min,LIU Fusheng,et al
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| Abstract: |
| 【Objective】This study investigated the characteristics of unsteady heat conduction of the back wall of solar greenhouse at night to provide basis for improving the heat releasing ability of back wall.【Method】In the test greenhouse in Tai’an,Shandong,test points were set up at 0.1,1.1,2.1,3.1,and 4.1 m on the back wall and at ground 0.1 m away from the back wall.The temperature and heat flow density of each test point were measured every 1 hour from 18:00 to 06:00 of the following day on a sunny day and a cloudy day in winter,2015.The change rate of temperature at each test point,the integral value of heat flow density,the internal heat transfer of the back wall,and the heat flow between the back wall and the ground were calculated.The relationship between heat storage and heat releasing volume at different heights of back wall,the relationship between the ground temperature and the back wall temperature,the internal heat transfer of the back wall,and the heat flow between the back wall and the ground surface were studied.【Result】The variations of heat storage in the middle and upper parts of the back wall were basically the same and larger than that in the lower part during sunny night.The heat-releasing volumes of the middle and upper parts of the back wall firstly decreased gradually and then tended to be steady.The temperature of the back wall was higher than the ground temperature before midnight and lower than that after midnight,and there was heat flow between the back wall and the ground.The internal heat migration flow from the middle and upper parts to the lower part was 14.2% of the total heat-releasing volume of the back wall.The variations of heat storage in the middle and upper parts of the back wall during cloudy night were basically the same and larger than that in lower part,the heat releasing volume increased gradually from the upper part to the lower part, and the temperature of the back wall was lower than that of the ground.The heat flow volume during cloudy night from the back wall to the ground was 3% of the total heat-releasing volume of the back wall,and the internal heat migration flow from the middle and upper parts to the lower part was 25.5% of the total heat releasing volume of the back wall.【Conclusion】The heat releasing volumes at different heights of the back wall are affected by the wall height,and heat storages at different heights of the back wall.The effect of the wall height is existing in the whole heat releasing process,and the effect of heat storage of the back wall is mainly at early period.There is heat migration flow of internal back wall. |
| Key words: solar greenhouse greenhouse back wall unsteady heat conduction heat migration flow |
