Papers by Jhih-Lin Chen
作物、環境與生物資訊, Mar 2017
農作物生產過程遭受強風吹襲而造成損失，防風網的利用是一種低成本及施作簡易
之防災策略。本研究擬建立由計算流體力學(CFD) 評估最適化防風網架設條件，作為提
供農作物防風技術之參考依據。試驗... more 農作物生產過程遭受強風吹襲而造成損失，防風網的利用是一種低成本及施作簡易
之防災策略。本研究擬建立由計算流體力學(CFD) 評估最適化防風網架設條件，作為提
供農作物防風技術之參考依據。試驗結果顯示，試驗田區架設不同網目及高度之防風
網，由實測風速變化以驗證CFD 模擬能力，結果顯示CFD模擬值與實際風場通過防風網
之減弱趨勢相符，可準確掌握風速流場，做為評估防風網效能之有效工具。另由評估結
果，防風網最佳阻風有效長度，水平距離為防風網高度之6 倍，有效高度為防風網高度
之1.3 倍。另由實際防風網在颱風期間之阻風效果案例分析，以70%百吉網阻風率可將18
m s-1 最大陣風降至4 m s-1，防風效果顯著。
Microfluidics and Nanofluidics, 2010
This paper demonstrates a three-dimensional, non-linear, AC electro-osmotic extensional flow indu... more This paper demonstrates a three-dimensional, non-linear, AC electro-osmotic extensional flow induced by the capacitive charging of a face-to-face pair of planar electrodes. These two planar electrodes facing each other had different sizes and shapes. The extensional flow was attributed to the rectification of the stagnation-point flow in the center region by the three-dimensional vortices at the corners of the smaller electrode. The measured flow velocity near the edge of the electrode was on the order of millimeters per second. The shape of the electrode affected the distribution of the electric field and thereby modified the electro-osmotic flow. A change in the shape of the smaller electrode would significantly affect the flow fields and could cause a variation of a factor of 10 in the measured flow velocity. An equivalent electronic circuit of the experimental apparatus was developed. Based on the equivalent electronic circuit, the calculated critical frequency was in good agreement with the measured optimal velocity frequency. The quadratic dependence of the velocity on the voltage drop across the liquid, a characteristic of the capacitive charging process, was also reported in this paper.
Sensors and Actuators B: Chemical, 2013
This paper is the first to report the mixing performance of an AC electro-osmotic (AC-EO) micromi... more This paper is the first to report the mixing performance of an AC electro-osmotic (AC-EO) micromixer based on the two sets of vortices generated by a face-to-face, asymmetric pair of planar electrodes. The larger top electrode of the asymmetric electrode pair was rectangular (30 × 60 mm2) and the much smaller bottom electrode was also rectangular (500 × 700 μm2) and featured two protrusions. Due to the highly three-dimensional flow pattern generated by the unique shape of the face-to-face electrode pair, the mixing enhancement factor (mixing time by diffusion/mixing time by the micromixer) exhibited by the reported micromixer ranged from 290 to 360 and the mixing performance values were uniform across the entire height of the fluid cavity. The usefulness of the mixer in hybridizing single-stranded deoxyribonucleic acids and mixing Escherichia coli with RNA stains was also demonstrated experimentally. A numerical investigation was conducted to study the three-dimensional AC-EO flow patterns induced by the face-to-face, asymmetric electrode pair. This analysis made it possible to identify a detailed flow pattern and the formation mechanism of the vortices. The confluence of inward AC-EO flows from the edges of the bottom-electrode protrusion locally induced a large inward-pumping force and was responsible for the formation of the four vortices at the four corners of the bottom electrode. The numerical and experimental results of this research provide information that will be useful in future applications and research in the area of microfluidic manipulation.
conference paper by Jhih-Lin Chen
本研究以計算流體力學來評估預計建於中東阿聯之魚菜共生溫室設計，其原始通風設計在兩側牆面與屋頂分別配置有百葉窗通風口及自然通風筒，參照了阿聯當地全年測站資料並假設幾種情況，全年平均風向以北風、西北... more 本研究以計算流體力學來評估預計建於中東阿聯之魚菜共生溫室設計，其原始通風設計在兩側牆面與屋頂分別配置有百葉窗通風口及自然通風筒，參照了阿聯當地全年測站資料並假設幾種情況，全年平均風向以北風、西北風為主，大氣溫度30℃與43℃(7~8月)時，全年大氣平均風速在2.5~4 m/s之間，我們配合氣象測站資料去推估溫室在自然通風下內外熱流場剖面的分佈情形；評估結果顯示，在自然通風狀態下，整體溫室平均溫度較室外大氣增加了6~10℃。建議的通風策略為側壁百葉開口與屋頂自然通風筒的開口面積可增大，將能增加通風比，達到溫室內整體的循環通風。側壁百葉開口盡可能與平均大氣風向垂直，才能獲得最佳的氣流交換率，意即溫室在建造時須讓側壁迎風面面向西北風。
本研究利用反應曲面法探討高壓噴霧降溫系統進行不同噴霧溫度、噴頭孔徑與噴霧壓力對溫室內溫度、噴霧粒徑與噴霧流量關係之研究，並將該系統安裝於開頂溫室中，進行設施內部降溫、加濕效率與使用效益面向之評估... more 本研究利用反應曲面法探討高壓噴霧降溫系統進行不同噴霧溫度、噴頭孔徑與噴霧壓力對溫室內溫度、噴霧粒徑與噴霧流量關係之研究，並將該系統安裝於開頂溫室中，進行設施內部降溫、加濕效率與使用效益面向之評估。將分析結果之設施內溫度、噴霧粒徑及噴霧流量三項反應性狀利用中心組合因子設計（central composite design, CCD）建立其迴歸模式，評估高壓噴霧系統之最適操作參數。溫室上方開頂面積與四周側邊下方開口面積分別固定於45%與34%，並將上述三項反應性狀之等高線圖重疊後可得噴霧最適溫度為10~11℃；噴頭最適孔徑為0.16~0.18mm；噴霧最適壓力為96~107 kgf/cm2。依上述之最適操作條件進行實際量測，所得之設施內溫度為29.6℃、噴霧粒徑為15.5μm及噴霧流量為1.42 L/min。本研究所得之實驗結果除了可提供高壓噴霧降溫系統實際操作所需之參考資料，更可發揮開頂溫室之最大降溫效益。
本研究旨在探討栽培環境之單日日照總量對不同型態的立體化層架之影響，全球農業為因應氣候變遷，眾多農作物利用簡易溫室與環控設備來進行栽培，以提升穩定農產品的供應，並希望降低成本增加其經濟效益，常使用... more 本研究旨在探討栽培環境之單日日照總量對不同型態的立體化層架之影響，全球農業為因應氣候變遷，眾多農作物利用簡易溫室與環控設備來進行栽培，以提升穩定農產品的供應，並希望降低成本增加其經濟效益，常使用立體化層架作為生產模式，但其下方層架之日照量會產生不足的情況。因此，本研究在1.3 m × 1.3 m的種植面積下，以坊間常用之A字型層架為基準，設計了三種不同的形式，並量測日照強度與單日日照總量，探討日照利用率之情形。實驗結果顯示：傳統的A字型層架，種植面積可增加39 %，其栽培最大高度為78 cm，上層日照利用率為87 %，但中、下層則減為60 %與48 %。因此，本研究設計出三種立體化層架栽培模式，其種植面積皆可增加113~150 %，口字型三層對稱與口字型五層交錯之層架，其作物高度皆能提升到53 cm，最上層日照利用率為85 %以上，其他層則為40~50 %之間。金字塔型五層層架作物高度為20 cm，其最上層日照利用率為89 %以上，其他層則為31~34 %之間。依據上述的日照量測值，可安排作物於每隔生長時期所需要的日照總量作為分層栽培，有效充分利用不同光照量增進栽培產量，提高農民的經濟效益。
本研究以開頂溫室為對象，利用一般通風型的開頂溫室、風扇水牆與低溫微霧系統三種降溫模式進行蒸發冷卻的降溫試驗，以評估此三種降溫模式之降溫效益。傳統鼓風式噴霧降溫系統，利用擾流風扇搭配常溫細霧，由於... more 本研究以開頂溫室為對象，利用一般通風型的開頂溫室、風扇水牆與低溫微霧系統三種降溫模式進行蒸發冷卻的降溫試驗，以評估此三種降溫模式之降溫效益。傳統鼓風式噴霧降溫系統，利用擾流風扇搭配常溫細霧，由於水霧溫度較高之故，使溫室內降溫效果不及低溫微霧。因此，本研究利用低溫微霧空調系統，以100kgf/cm2壓力噴出10℃低溫微霧，利用熱氣上升冷氣下降原理，將高溫、高濕的氣體排出設施外，有效控制及改善溫室內溫、濕度，達到較佳降溫效果。實驗結果顯示：當中午12時，其室外大氣溫度為34.8℃，沒有任何降溫設備之開頂溫室內溫度受到太陽輻射和熱累積的影響，室內高溫、濕度達38.8℃與50.7％；風扇水牆降溫模式，在10點啟動後，其中午溫室內溫、濕度為31.2℃與78.5％；在此期間，低溫微霧降溫系統的作用下配合開頂溫室的通風性，溫、濕度保持在29.1℃和濕度為75.8％。降溫幅度較大氣溫度下降5~6℃，且無溫度梯度的產生，室內氣溫狀態變化呈現平穩狀態，相較一般通風型的開頂溫室以及風扇水牆系統，低溫微霧系統有較佳的降溫成效。
目前台灣溫室生產在夏季普遍存在著高溫問題，過高的溫度除不利作物生長外對農業從事人員之健康也有不良的影響，為避免溫室內溫度過高，農業生產者常將設施高度提高，但設施高度越高建置成本越高，且其抗風能力... more 目前台灣溫室生產在夏季普遍存在著高溫問題，過高的溫度除不利作物生長外對農業從事人員之健康也有不良的影響，為避免溫室內溫度過高，農業生產者常將設施高度提高，但設施高度越高建置成本越高，且其抗風能力也會受到影響，因此有必要針對設施高度與內部溫度之相關性做合理性評估，本研究之目的在探討溫室設施高度差異與室內溫度間之關聯性，進而建立一套模式以描述設施高度對內部溫度的影響。在地理位置且溫室類型相同但不同高度、季節的條件下利用CFD技術模擬室內溫度變化狀況，使用工具為Fluent軟體及其內建之太陽輻射模組，模擬溫室內熱傳變化情形，並參考實測氣象資料修正太陽輻射值以更符合台灣地區現況，並在3組高度分別為2M、3M、4M的溫室中每隔1M與室外各架設一隻E-type熱電偶溫度計，以期能了解不同高度之溫室內部氣溫的變化情形，並與CFD模擬之結果進行比較與分析，了解在相同條件下，溫室每升高1公尺內部氣溫可下降幾度。
The cooling principle of open-top greenhouse is taking advantage of vertical convection of air ca... more The cooling principle of open-top greenhouse is taking advantage of vertical convection of air caused by thermal buoyancy to expel the hot air from the greenhouse. For cooling in the greenhouse in summer, many studies have demonstrated a significant effect. But the problem of the accumulated heat in the greenhouse is greatly affected by the meteorological environment of the geographical location. Even in the same area, environmental conditions inside the greenhouse vary due to different conditions, such as seasons, temperature difference between day and night, building type, surrounding environment and so on. Therefore, it's difficult to make an overall assessment of the effect provided by the open-top greenhouse in a traditional way. Using CFD (Computational Fluid Dynamics) technology to make the analysis of cooling effect in open-top greenhouse does not require a lot of resources to build physical facilities, but is able to achieve a certain effect. Therefore, the study is conducted to do simulation for the existing open-top greenhouse at the Taiwan Agricultural Research Institute (TARI), Council of Agriculture, Executive Yuan. Meanwhile inside and outside the greenhouse, temperature and humidity sensors of WSN (Wireless sensor network, WSN) transmission interface and a simple meteorological station are set up to record and verify the observations with the simulation results. It is expected to build the techniques of assessing cooling effect by estimating the temperature distribution within the greenhouse according to meteorological data of outdoor environment. Based on the results obtained from this study, it showed that the top temperature in the greenhouse can be dropped by about 3.7 ℃ at noon for the open-top greenhouse without any cooling equipment. The simulation results also showed a consistent trend with those observations. From this study, when the settings of the CFD simulation conditions are properly provided, the simulation of cooling in the greenhouse with CFD has a very high credibility. Hence, it is feasible to analyze in this way. It is suggested that assessment by using CFD technology be conducted first before building a physical greenhouse facility to improve project quality and reduce design errors.
Drafts by Jhih-Lin Chen
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Papers by Jhih-Lin Chen
之防災策略。本研究擬建立由計算流體力學(CFD) 評估最適化防風網架設條件，作為提
供農作物防風技術之參考依據。試驗結果顯示，試驗田區架設不同網目及高度之防風
網，由實測風速變化以驗證CFD 模擬能力，結果顯示CFD模擬值與實際風場通過防風網
之減弱趨勢相符，可準確掌握風速流場，做為評估防風網效能之有效工具。另由評估結
果，防風網最佳阻風有效長度，水平距離為防風網高度之6 倍，有效高度為防風網高度
之1.3 倍。另由實際防風網在颱風期間之阻風效果案例分析，以70%百吉網阻風率可將18
m s-1 最大陣風降至4 m s-1，防風效果顯著。
conference paper by Jhih-Lin Chen
Drafts by Jhih-Lin Chen
之防災策略。本研究擬建立由計算流體力學(CFD) 評估最適化防風網架設條件，作為提
供農作物防風技術之參考依據。試驗結果顯示，試驗田區架設不同網目及高度之防風
網，由實測風速變化以驗證CFD 模擬能力，結果顯示CFD模擬值與實際風場通過防風網
之減弱趨勢相符，可準確掌握風速流場，做為評估防風網效能之有效工具。另由評估結
果，防風網最佳阻風有效長度，水平距離為防風網高度之6 倍，有效高度為防風網高度
之1.3 倍。另由實際防風網在颱風期間之阻風效果案例分析，以70%百吉網阻風率可將18
m s-1 最大陣風降至4 m s-1，防風效果顯著。