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| 基于CFD的不同走向大跨度保温型温室温度场模拟 |
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方慧1,2, 杨其长1,2, 张义1,2, 程瑞锋1,2, 张芳1,2, 卢威1,2, 刘焕1,2
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| (1.中国农业科学院 农业环境与可持续发展研究所, 北京 100081;2.农业部设施农业节能与废弃物处理重点实验室, 北京 100081) |
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| 摘要: |
| 大跨度保温型温室是针对日光温室之间南北间距较大，土地利用效率不高而设计的。该温室可将日光温室南北间距缩减为2 m以内，同时具有日光温室的良好保温特征，但一直以来缺乏对该大跨度保温型温室的光温性能评价。本研究利用计算流体力学软件（Computational fluid dynamics，CFD）构建三维稳态温室模型，模拟不同走向对温室光温环境的影响，为温室建设提供理论依据。在模型中采用太阳射线追踪法加载太阳辐射，通过离散坐标辐射模型（Discrete ordinates，DO）模拟热辐射的影响。将模拟结果与试验测量结果进行对比，模型模拟值与实测值绝对偏差在0.3~2.1℃范围内，验证了构建的CFD温室模型的准确性。利用已验证的模型模拟结构尺寸完全相同，走向分别为东西与南北的2栋温室内的温度场分布情况，比较分析不同时刻（6个案例）温室内温度场差别。模拟结果表明，在上午10：00和下午14：00，2种走向温室内温度差异不明显在正午12：00，南北走向温室内温度比东西走向温室高2.8℃。在室温分布均匀性方面，利用CFD后处理软件提取6个案例在每一节点处的模拟值，统计6个案例温室温度的相对标准偏差，结果表明，在早、中、晚的3个时间段内，南北走向温室的RSD值均低于东西走向温室。综合模拟与测试结果表明，双拱大跨度保温型温室在北方地区应选用南北走向，温室的光照分布、温度分布都优于东西走向。 |
| 关键词: 温室 计算流体力学 预测模型 温度均匀性 |
| DOI：10.11841/j.issn.1007-4333.2017.11.15 |
| 投稿时间：2016-09-29 |
| 基金项目:国家自然科学基金项目（51508560）；科技部"863"计划课题（2013AA102407）。 |
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| Prediction model on air temperature in large-span greenhouse with different orientation based on CFD |
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FANG Hui1,2, YANG Qichang1,2, ZHANG Yi1,2, CHENG Ruifeng1,2, ZHANG Fang1,2, LU Wei1,2, LIU Huan1,2
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| (1.Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China;2.Key Laboratory of Energy Conservation and Waste Management of Agriculture Structures, Ministry of Agriculture, Beijing 100081, China) |
| Abstract: |
| In order to increase land utilization efficiency and decrease the necessary distance between two adjacent greenhouses to prevent shading,a south-north large scale greenhouse was designed to substitute conventional east-west direction greenhouse.To assess the performance of the newly designed greenhouse,a prediction model on temporal and spatial variations of air temperature based on the computational fluid dynamics (CFD) technique was established.Discrete ordinates (DO) radiation model was used to simulate the radiation heat transfer in greenhouses.Solar radiation values were calculated by solar ray tracing method.In order to validate the effectiveness of the prediction model,the spatial and temporal distribution values of air temperature were measured and compared with the simulated data.The results showed that the errors between simulated and measured air temperature at the observation points varied from 0.3 to 2.0℃ and the predicted values matched the measured values.The validated CFD model was then used to further analyze the temperature differences in new type greenhouses with south-north and east-west direction at different time.The simulation results showed that the average indoor air temperature difference in both greenhouses was very small at 10:00 am and 14:00 pm.It was because the sun zenith angle is small during the morning and afternoon,meaning that the solar incident angle is big,and the solar radiation transmissivity is small at 12:00 am.The air temperature in south-north greenhouse was 2.8℃ higher than in the east-west greenhouse at 12:00 am.Relative standard deviation (RSD) was also used to evaluate climate uniformity based on the air temperature distribution.The RSD values of 6 combination scenarios were calculated.The study showed that the south-north greenhouse had lower RSD values compared to the east-west greenhouse meaning more climate uniformity of the south-north greenhouse. |
| Key words: greenhouse computational fluid dynamics prediction model temperature uniformity |
