通風策略於農作物與建築規劃之模擬分析

The simulation of ventilation strategies for crop and architectural arrangement

張育豪(Yu-Hao Chang)

指導教授 ： 蔡建雄

國立屏東科技大學/工學院/車輛工程系所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00170

摘要

在溫室通風系統中，通風效果受到外界環境、溫室建築結構設計及作物擺設所影響，為了提升對環境資源的利用與降低對能源的浪費，本研究利用計算流體動力學的方式輔助溫室的通風系統設計，建立一套有效的通風模式。
在蔬果溫室的模擬結果中，開窗面積越大有助於提升溫室通風量與層架內的平均速度，但對於層架內風速均勻度則無太大影響，當風向-45°時，層架內風速均勻度維持在0.2-0.7之間。風速的影響則同開窗面積影響，當風向45°時，不同風速變化的層架風速均勻度範圍為0.3-0.7之間，但風速越大，可提升單位面積的通風量。在不同風向時最先影響的層架亦不相同，最先影響的層架具有較高的平均風速，但風速均勻度較差。在通風量評估，迎風面積越大通風量越高，但以垂直窗口之風向具有較佳單位面積通風量數值。外推窗角度的通風影響得知，外推窗具提升與降低溫室通風量功能，以外推角度平行風向時可得到最高的通風量，且外推窗設計可改善最先影響層架內的風速均勻度，範圍從0.6-0.8下降至0.3-0.6。研究中也顯示排風扇散熱速率受到整體入風窗口面積影響，在相同排風扇風量與數量情況下，入風窗口面積越大散熱速率越快。

在農作物通風特性模擬結果中，顯示靈芝表面通風特性受到擺設角度的影響，在擺設角度180度時靈芝受到的遮蔽作用的影響較小，表面熱對流係數分布較高也均勻。研究中也顯示風向角度對萵苣在不同時期所產生的通風影響亦不相同，受限於植株大小與水槽寬度，幼苗期的萵苣在風向90度時，葉子正面與背面同時可以獲得較高的熱對流係數，成熟期的萵苣在風向-90度時，葉子正面及背面獲得的較佳的熱對流係數。

關鍵字

計算流體力學 ； 均勻度 ； 通風 ； 溫室 ； 農作物

並列摘要

The efficiency of ventilation in the greenhouse is determined by the external environment and the structure of the greenhouse. In order to enhance the use of the resource and reduce the waste of energy. A simulation model by CFD was established in this study to assist in designing ventilation system.Because of the influence of window structure, air flow is rapid and concentrated when through the window. The average velocity of the district where closer the windward window is higher than farther ones. On the contrary, the uniformity of velocity in the area becomes higher. The simulation results indicate the angle of window can’t only effectively drop the uniformity of velocity, but also improve the ventilation flux. The simulation result of installing exhaust fan has pointed out that in the same ventilation flux of exhaust fans, the efficiency of heat dissipation is determined by size of intake.Though the simulative result of the crop, the display manners of ganoderma lucidum which affect efficiency of ventilation are analyzed. It has better efficiency of ventilation when the display manners of ganoderma lucidum are facing the wind. In the result of lettuce ventilation analysis,the way which wind blows from top to bottom has better efficiency of ventilation
both sides of leaf because the sheltering effect is lower than the other way. When lettuce is ripe, the reverse of the leaf has a higher distribution of heat transfer coefficient in the way which wind blows from bottom to top.

並列關鍵字

CFD ； uniformity ； ventilation ； crop ； greenhouse

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