微落膜反應器之模擬研究

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Title:	微落膜反應器之模擬研究
Other Titles:	Simulation study of micro falling film reactors
Authors:	李協聰;Li, Hsieh-hsung
Contributors:	淡江大學化學工程與材料工程學系碩士班張煖;Chang, Hsuan
Keywords:	微落膜反應器;多相流;CFD;VOF model;接觸角度;膜厚;Micro falling reactors;multiphase flow;CFD;VOF model;Contact angle;Film thickness
Date:	2010
Issue Date:	2010-09-23 17:32:54 (UTC+8)
Abstract:	微落膜反應器可提供遠高於傳統裝置之單位體積介面面積與熱質傳係數，適合於高熱效應之快速反應，也是程序強化之一種重要單元。由於涉及氣液兩相之流動，其模擬較為困難。本論文利用計算流體力學軟體(Computational Fluid Dynamics，CFD)，採用FLUENT內之流體體積(Volume of Fluid, VOF)模式，模擬微落膜反應器內之流力與熱傳特性。比較二維與三維模式之模擬結果，顯示當接觸角度為90°時，二者之結果接近，然而接觸角度為60°時差異則相當大。使用二維模式，本論文完成了各項條件改變之影響分析，包括氣體流量、液體流量、液體黏度、液體密度、表面張力、壓力差、傾斜角度，探討之系統特性則包括收斂之液體流量、液膜厚度與波動程度、速度分佈與壓力分佈。模擬之液膜厚度，與文獻之實驗結果相同，與Kapitza方程式之計算值最接近。模擬之納賽數比文獻之關聯式預測値高了38 ~ 93%。 Micro falling film reactor (MFFR) provides much higher interfacial area per unit volume as well as heat and mass transfer coefficients than traditional devices. MFFR is particularly suitable to highly exothermic and rapid reactions and is one of the important units for process intensification. However, MFFR is difficult to simulate due to the interaction between the gas and liquid phases. The thesis studies the hydrodynamics and heat transfer for a micro structured falling film reactor by CFD (Computational Fluid Dynamics) simulation using the Volume of Fluid (VOF) model in FLUENT. Comparison of the 2D and 3D simulations indicates that 2D and 3D simulations provide similar results for the case of 90° contact angle, but are significantly different for the case of 60°contact angle. By the 2D simulation, the effects of various system parameters, including the fluid flow rates, liquid density and viscosity, surface tension, pressure drop and angle of inclination, on the phase, velocity and pressure profiles, are investigated. The film thickness results are close to that from Kapitza’s equation, which coincides with the conclusion of comparing experimental results from the literature. The Nusselt number results from simulation are higher than the predictions from a correlation for traditional devices by 38-93%.
Appears in Collections:	[Graduate Institute & Department of Chemical and Materials Engineering] Thesis

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