以電化學量測法與計算流力模擬法微觀探討內置間隔網流道內之輸送現象

Transport Phenomena in Spacer-filled Channel - An Inside Understanding by Electrochemical Measurement and CFD Simulation.

林敬恩(Ching-En Lin)

指導教授 ： 童國倫

中原大學/工學院/化學工程研究所/碩士(2007年)

https://doi.org/10.6840/cycu200700301

摘要

過去針對間隔網薄膜模組內之質傳研究中，大多只探討整體的質傳現象，卻忽略了間隔網小單元內的局部輸送行為。因此本研究利用一種電化學技術－流體動態式伏安法，微觀探討流道內之局部輸送現象。此外，藉由計算流力之輔助分析，更進一步了解固液交界面之分布情形與流道內之流體行為。
本文內容針對不同流道和間隔網流道入口數探討對局部剪應力大小、質傳速率、表面濃度變化及濃度邊界層厚度之影響。研究發現從間隔網小單元內之局部剪應力大小與分佈情形顯示，在距離4/5間隔網纖維間距位置時，最大的局部剪應力值出現在間隔網小單元內之中間線兩側。而在彎曲式流道系統內，從實驗獲得的質傳速率與局部剪應力加上數值模擬結果顯示，內側壁面所得到的質傳效果都比外側壁面高。
綜合以上實驗技術及計算流力之研究，電化學實驗提供諸多瞭解液體界面微觀現象的訊息，數值模擬則提供系統內的巨觀現象，因此本文提供了有助於了解其他薄膜模組內微觀探討流體流態及質傳效率之分析方法。

關鍵字

電化學方法 ； 極限電流 ； 局部剪應力 ； 計算流力 ； 間隔網

並列摘要

Understanding the transport phenomena in a spacer-filled channel was conducted using computational fluid dynamic (CFD) and electrochemical techniques. The spacer serves as vortex promoters for reducing polarization phenomena near the membrane surface. No any effort has been placed on the location of unit cell in the spacer-filled channel on hydrodynamic and concentration boundary layers near the membrane surface.
Purposes of this work were focused on the effects of different channels and the sums of entrance on the mass transfer rate, shear stress and flow filed by CFD and experimental equipment. Results showed that the maximum wall shear stress was occurred beside the 4/5 position of the center line of the unit cell. The mass transfer rate of the inner wall was higher than that of outer wall in the curved channel.
Therefore, a platform was constructed based on the CFD approach and technique of electrochemical measurement for microcosmic study of membrane module design.

並列關鍵字

electrochemical method ； spacer ； computational fluid dynamics ； local shear stress. ； limiting current

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