作物對溫室風壓通風影響之研究;Wind-driven Natural Ventilation of Greenhouses with Vegetation

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Title:	作物對溫室風壓通風影響之研究;Wind-driven Natural Ventilation of Greenhouses with Vegetation
Authors:	藍廷維;LAN, TING-WEI
Contributors:	土木工程學系
Keywords:	溫室;風壓通風;計算流體動力學模式;大渦模擬;風洞實驗;孔隙阻力;Greenhouse;Wind-driven ventilation;Computational Fluid Dynamics;Large Eddy Simulation;Wind tunnel experiment;Porous drag
Date:	2017-07-26
Issue Date:	2017-10-27 12:15:58 (UTC+8)
Publisher:	國立中央大學
Abstract:	臺灣地區夏季太陽輻射強、氣溫高，造成農業設施、溫室內部溫度過高，不適合作物的生長環境，故降低溫室內部溫度為設計溫室必要之考慮因素。自然通風因為可以不耗費電力，廣為簡易型溫室所採用。但缺點是通風量隨室外大氣風速、風向、溫度而變，通風量不易控制。本研究利用風洞實驗及計算流體動力學模式研究溫室長度對風壓通風之影響，研究成果發現縱深長的溫室，通風量小於縱深短的建築物。造成此現象的原因有兩個：(1)縱深短的溫室，迎風、背風面之間的壓差較大，導致通風量較大；(2)縱深長的建築物，室內阻力使得通風量較小。當溫室長度L大於溫室室內高度6倍時，室內阻抗便不可忽略。並使用孔隙阻力模式探討溫室內部作物對風壓通風之影響，對比模擬結果與實驗量得之風速來校驗孔隙阻力模式中之係數，因此數值模式可正確地預測溫室內部風場且量化溫室內作物對於風壓通風之影響。此外，本研究亦探討單斜室溫室在不同開口設置及風向下對風壓通風之影響，研究結果顯示當溫室背風面底部與屋頂皆有開口時通風量最大，且屋頂開口能夠有效的增加通風量。;This study uses wind tunnel experiment and a Large Eddy Simulation (LES) model to investigate the wind-driven ventilation of greenhouses with vegetation inside. The simulation results are validated by wind tunnel experiments. Then the numerical model is used to examine the influences of opening configuration, indoor vegetation on the ventilation rate. The simulation results reveal that the windward pressure was independent of the greenhouse length, while the suction pressure on the leeward side of the single greenhouse is larger than that of multi-span greenhouse. In other words, the pressure difference of single-span greenhouse is larger than that of multi-span greenhouse, and lead to a larger ventilation rate. In addition, multi-span greenhouse has larger internal resistance than that of single-span greenhouse. The ventilation rate can be predicted by a resistance model. The numerical results indicate that the porous drag model is able to predict the velocity distribution inside the greenhouse, and the resistance model can be used to assess the influences of vegetation on the ventilation rate. The results also demonstrate that the ventilation rate is influenced by the inlet and outlet opening areas. Furthermore, the roof opening can substantially increase the ventilation rate in multi-span monoslope greenhouses.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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