薄膜流體接觸器之計算流體力學模擬研究

CFD simulation study of membrane-based fluid contacting separators

陳許豐(Hsu-Feng Chen)

指導教授 ： 張煖

共同指導教授 ： 張正良

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2015年)

https://doi.org/10.6846/TKU.2015.00528

摘要

本研究利用計算流體力學(Computational Fluid Dynamics, CFD)模擬探討薄膜接觸器應用於鹽水脫鹽與二氧化碳吸收之流力與熱質傳特性。薄膜接觸器使用多孔疏水性膜且模組型式包括空通道與具網狀間隔物通道。本研究使用FLUENT軟體之層流模式與VOF(Volume of Fluid)多相模式，薄膜為可滲透邊界條件。模式之驗證是利用文獻實驗數據且獲得相當接近之結果。
具間隔物模組之流力與熱質傳特性皆會受到間隔物配置之影響，而呈現上下震盪之變化，其壓降、熱傳係數與質傳係數均高於空通道。間隔物通道與空通道之濃度邊界層厚度分別約為1 mm與2-4 mm。使用具間隔物通道可大幅提升鹽水脫鹽系統與碳酸丙烯酯之二氧化碳物理性吸收系統之質傳通量。間隔物通道之水利損耗遠高於空通道，後者接近平板通道關聯式預測值。間隔物與空通道之熱傳係數與質傳係數均與文獻報導關聯式之預測值有很大偏差。

關鍵字

計算流體力學 ； 薄膜蒸餾 ； 薄膜吸收 ； 流力 ； 熱傳 ； 質傳 ； 間隔物

並列摘要

In this thesis, the fluid flow, heat and mass transfer characteristics in the membrane contactors for desalination and carbon dioxide physical absorption with propylene carbonate are studied using computational fluid dynamics (CFD) simulation. For desalination, the membrane modules are direct contact type. The membrane contactors simulated use hydrophobic membranes and either empty or spacer-filled channels. The laminar flow model and Volume of Fluid (VOF) multiphase model in FLUENT are employed with the membranes defined as permeable boundary conditions. The model simulation results are fairly close to the literature experimental data
The fluid flow, mass and heat transfer characteristics of spacer-filled channels show fluctuating patterns corresponding to the spacer configurations. The pressure drop, heat and mass transfer coefficients of spacer-filled channels are all higher than the empty channels. The concentration boundary layer thicknesses of spacer-filled and empty channels are approximately 1 mm and 2-4 mm, respectively. For both desalination and carbon dioxide absorption systems, the spacers significantly enhance the transmembrane mass fluxes. The hydraulic power consumptions of spacer-filled channels are much higher than the empty channels, which are close to the correlation for parallel-plate channels. The heat and mass transfer coefficients of both spacer-filled and empty channels are not close to the literature reported correlations.

並列關鍵字

Computational fluid dynamics ； Membrane distillation ； Membrane absorption ； Hydrodynamics ； Heat transfer ； Mass transfer ； Spacer

參考文獻

許建安. (2014). 薄膜蒸餾傳輸特性之計算流體力學研究. 淡江大學化學工程與材料工程學系碩士班學位論文, 1-154.

Ahmad, A. L., Lau, K. K., & Bakar, M. A. (2005). Impact of different spacer filament geometries on concentration polarization control in narrow membrane channel. Journal of Membrane Science, 262(1), 138-152.

Al-Sharif, S., Albeirutty, M., Cipollina, A., & Micale, G. (2013). Modelling flow and heat transfer in spacer-filled membrane distillation channels using open source CFD code. Desalination, 311, 103-112.

Amrei, S. M. H. H., Memardoost, S., & Dehkordi, A. M. (2014). Comprehensive modeling and CFD simulation of absorption of CO2 and H2S by MEA solution in hollow fiber membrane reactors. AIChE Journal, 60(2), 657-672.

Reed, B. W., Semmens, M. J., & Cussler, E. L. (1995). Membrane contactors.Membrane Science and Technology, 2, 467-498.