环流风机布置对温室内流场影响的CFD模拟
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摘要
为了解大肩高连栋玻璃温室夏季机械通风时室内流场分布,提高机械通风的降温效果,建立了6m肩高温室机械通风工况下的CFD模型,并对模拟结果进行了试验验证,结果表明:模拟值和试验值的最大相对误差为6. 70%,平均相对误差为2. 87%,显示CFD数值模型有效。在CFD模型基础上,进一步对不同环流风机布置下机械通风的降温效果进行了分析,结果表明:使用环流风机可提高机械通风的降温范围,在湿帘风机方向上实现气流的"接力",温室作物冠层南北温度差减小0. 5℃,32℃以下区域增加了20%;在环流风机安装方向上,不同横向截面上反向布置时室内冷热空气混合更好,室内温度分布更加均匀。
In order to understand the distribution of indoor flow field during mechanical ventilation of greenhouse in summer and improve the cooling effect of mechanical ventilation,a CFD model for mechanical ventilation of a 6 m greenhouse was established,and the simulation results were verified by experiments. It showed that the maximum relative error of the simulated value and the experimental value was 6. 70%,and the average relative error was 2. 87%,which proved that the CFD numerical model was effective. Based on the model,the cooling effect of mechanical ventilation under different circulation fan arrangement was analyzed. It was concluded that the use of circulation fans could increase the cooling range of mechanical ventilation. The temperature difference in crop canopy from north to south decreased by 0. 5℃,and the areabelow 32°C increased by 20%. In the installation direction of the circulation fan,the indoor hot and cold air mixed better and the indoor temperature distribution was more uniform in the reverse arrangement.
In order to understand the distribution of indoor flow field during mechanical ventilation of greenhouse in summer and improve the cooling effect of mechanical ventilation,a CFD model for mechanical ventilation of a 6 m greenhouse was established,and the simulation results were verified by experiments. It showed that the maximum relative error of the simulated value and the experimental value was 6. 70%,and the average relative error was 2. 87%,which proved that the CFD numerical model was effective. Based on the model,the cooling effect of mechanical ventilation under different circulation fan arrangement was analyzed. It was concluded that the use of circulation fans could increase the cooling range of mechanical ventilation. The temperature difference in crop canopy from north to south decreased by 0. 5℃,and the areabelow 32°C increased by 20%. In the installation direction of the circulation fan,the indoor hot and cold air mixed better and the indoor temperature distribution was more uniform in the reverse arrangement.
引文
[1]张震,刘学瑜.我国设施农业发展现状与对策[J].农业经济问题,2015,36(5):64-70.
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[13]郑茂军,毛罕平.作物高度对温室自然通风影响的CFD分析[J].农机化研究,2016,38(5):20-23.
[14]李永欣,李保明,李真,等. Venlo型温室夏季自然通风降温的CFD数值模拟[J].中国农业大学学报,2004(6):44-48.
[15]孙帮成,李明高. ANSYS FLUENT 14. 0仿真分析与优化设计[M].北京:机械工业出版社,2014:17-20.
[2] Bournet P E,Saould K,Boulard T. Numerical prediction of the effect of vent arrangements on the ventilation and energy transfer in a multi-span glasshouse using a bi-band radiation model[J]. Biosystems Engineering,2007,98(2):224-234.
[3]谭胜男.基于CFD的现代化温室环境数值模拟与优化研究[D].南京:南京农业大学,2013.
[4] Dayan E,Fuchs M,Plaut Z,et al. Cooling of roses in greenhouses.[J]. Acta Horticulturae,2000,534:351-360.
[5] Flores-Velazquez J,Montero J I,Baeza E J,et al. Mechanical and natural ventilation systems in a greenhouse designed using computational fluid dynamics[J]. International Journal of Agricultural and Biological Engineering,2014,7(1):1.
[6]黄全丰,赵云.机械通风温室夏季内部温度场及动态特性CFD模拟[J].农机化研究,2013,35(1):30-33.
[7]张树阁,宋卫堂,滕光辉,等.湿帘风机降温系统安装高度对降温效果的影响[J].农业机械学报,2006(3):91-94.
[8] Zhang X,Wang H,Zou Z,et al. CFD and weighted entropy based simulation and optimisation of Chinese Solar Greenhouse temperature distribution[J]. Biosystems Engineering,2016,142:12-26.
[9]胥芳,蔡彦文,陈教料,等.湿帘-风机降温下的温室热/流场模拟及降温系统参数优化[J].农业工程学报,2015,31(9):201-208.
[10]孙迎龙,王新忠.光伏玻璃温室自然通风条件下的CFD模拟验证[J].农机化研究,2015,37(4):176-179.
[11]周伟,汪小旵,李永博.可变边界条件下的Venlo温室温度场三维非稳态模拟[J].农业机械学报,2014,45(11):304-310.
[12]吴飞青,张立彬,胥芳,等.机械通风条件下玻璃温室热环境数值模拟[J].农业机械学报,2010,41(1):153-158.
[13]郑茂军,毛罕平.作物高度对温室自然通风影响的CFD分析[J].农机化研究,2016,38(5):20-23.
[14]李永欣,李保明,李真,等. Venlo型温室夏季自然通风降温的CFD数值模拟[J].中国农业大学学报,2004(6):44-48.
[15]孙帮成,李明高. ANSYS FLUENT 14. 0仿真分析与优化设计[M].北京:机械工业出版社,2014:17-20.
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