本研究提出了計算流體動力學（Computational Fluid Dynamics）和螺旋環不規則填料流體力學行為的實驗驗證。不規則填料已廣泛應用化工業界，如吸收、提取等。到目前為止，發展新型不規則填料結構是需高度經驗的。即便隨著計算能力的提高，文獻中也很難找到關於不規則填料的文章。填料結構的不規則性和堆疊的幾何形狀使得可接受的網格生成和收斂非常困難，因為當大量堆疊時，不規則堆疊的結構是非常複雜的。在本研究中開發螺旋環不規則填料中的逆流氣液流動CFD模型。重力模擬用於生成不規則堆疊結構。而利用一種簡單的回饋控制來控制氣體入口流量，從而獲得特定的壓力。多相模型被用來計算氣體和液體的相互作用，其中表面張力和壁面接觸角被認為是關鍵因素。CFD模型透過實驗室級的吸收塔進行驗證。結果與拉西環相比，螺旋結構確實增加了液氣界面面積，持液率，且壓力降更低，可以承受更大的液氣進料流率比。總結，本研究發展了一種可以獲得合理的填料流體力學行為的CFD模型，而設計微觀結構加入填充料單元，將提升其流體動力學性能表現。這些CFD模擬結果可作為合理的填充料設計基礎。

This study presented computational fluid dynamics (CFD) and experimental validation of hydrodynamic behavior of helical rings random packing. Random packings have been widely used in chemical industries in absorbers, strippers etc. Up till now, development of novel random packing structure has essentially been empirical. Even with the increased computing power, CFD simulations of random packings are hard to find in the literature. The random nature of the packing structures, and the stacked geometry make acceptable grid generation and convergence very difficult because the structure of random packing is complicated when large amounts of it are stacked in a column. In this work, a CFD model was developed to simulate countercurrent gas-liquid flow in random packings formed by helical rings. Gravity simulation was used to generate stacking structures. A simple feedback control scheme was applied to control the gas inlet flow rate so that a particular pressure. Multiphase model was employed to compute the gas and liquid interaction in which the surface tension and wall contact angle were found as key factors. The predictions of the CFD model were validated with a lab-scale packed-bed absorber. It was found that the helical structure did increase the interfacial area, liquid hold-up when compared to Raschig rings, and such predictions can be validated by our in-house experiment. The model also showed that helical rings will have lower pressure drop and can sustain a larger liquid-gas ratios compared to Raschig rings . In summary, our study found that CFD simulations can obtain reasonable predictions of hydrodynamic behaviour of packings, and the inclusion of microstructures into a packing element will improve its hydrodynamic properties. These results showed that CFD can be used as a basis for rational packing design.

圖目錄 iv
表目錄 viii
摘要 ix
Abstract x
誌謝辭 xii
第一章 緒論 1
1.1文獻回顧 1
1.1.1CFD模擬規則填料 1
1.1.2 CFD模擬不規則填料 4
1.2研究動機與目的 6
第二章 模擬方法 7
2.1模擬軟體簡介 8
2.2數值方法介紹 9
2.3統御方程式 10
2.3.1連續方程式(Continuity Equation) 11
2.3.2動量守恆方程式(Momentum conservation equation) 12
2.3.3紊流方程式(Turbulence equation) 13
2.3.4表面張力(Surface tension) 14
2.3.5升力(Lift force) 14
2.3.6牆面潤滑力(Wall lubrication) 15
2.3.7拖曳力(Drag force) 15
2.4幾何設計 16
2.4.1填充物設計 16
2.4.2流場計算域設計 17
2.4.3填充物堆疊 19
2.4.4網格切割 21
2.5邊界條件設定 22
2.6穩態計算方法(steady-state calculation) 25
2.7 暫態計算方法(transit calculation) 26
第三章 實驗方法 27
第四章 結果與討論 29
4.1拉西環結果 29
4.1.1拉西環壓力降實驗結果 30
4.1.2拉西環模擬殘差 32
4.1.3拉西環模擬結果 35
4.2螺旋環結果 41
4.2.1螺旋環壓力降實驗結果 41
4.2.2螺旋環網格類型比較 42
4.2.3螺旋環模型交互作用影響討論 43
4.2.4螺旋環模擬殘差 45
4.2.5螺旋環模擬結果 48
4.2.6氣液接觸面積模擬討論 52
4.3拉西環與螺旋環結果比較 54
第五章 結論 56
Nomenclature 58
參考文獻 60

[1] N. McDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G.Jackson, C. S. Adjiman, C. K. Williams, N. Shah, and P. Fennell, "An overview of CO2 capture technologies," Energy & Environmental Science, vol. 3, pp. 1645-1669, 2010.
[2] J. Hodson, Fletcher J, Porter K. Fluid mechanical studies of structured distillation packings. Paper presented at: Institution of Chemical Engineers Symposium Series, 1997.
[3] Klöker, M., Kenig, E.Y., Gorak, A., “On the development of new
column internals for reactive separations via integration of CFD and
process simulation”, Catalysis Today, 79 (1-4), 479-485, 2003.
[4] Klöker, M., Kenig, E.Y., Piechoia, R., Burghoff, S., Egorov, Y.,
"CFD-based study on hydrodynamics and mass transfer in fixed
catalyst beds”, Chem. Eng. Technol., 28 (1), 31-36, 2005.
[5] Egorov, Y., Menter, F., Kloker, M., Kenig, E.Y., “On the combination
of CFD and rate-based modelling in the simulation of reactive separation processes”, Chem. Eng. Process., 44 (6), 631-644, 2005.
[6] Valluri, P., Matat, O. K., Hewitt, G. F., & Mendes, M. A. Thin film flow over structured packings at moderate Reynolds numbers. Chemical Engineering Science, 60, 1965-1975, 2005.
[7] A. Ataki and H. J. Bart, "Experimenatal and CFD simulaition study for the wetting of a structured packing element with liquids," Chemical Engineering & Technology, vol. 29, pp. 336-347, 2006.
[8] Chen, J., Liu, C., Yuan, X., & Yu, G. CFD simulation of flow and mass transfer in structured packing distillation columns. Chinese Journal of Chemical Engineering, 17, 381-388, 2009.
[9] Chen JB, Liu CJ, Li YK, Huang Y, Yuan XG, Yu GC. Experimental
investigation of single-phase flow in structured packing by LDV.
Chin J Chem Eng. 15:821–827, 2007.
[10] Haroun, Y., Raynal, L., & Legendre, D. Mass transfer and liquid hold-up determination in structured packing by CFD. Chemical Engineering Science, 75, 342-348, 2012.
[11] Raynal, L., Boyer, C., Ballaguet, J.P. Liquid holdup and pressure drop determination in structured packing with CFD simulations. The Canadian Journal of Chemical Engineering 82, 871-879,2004.
[12] Iliuta, I., & Larachi, F. Mechanistic model for structured-packing-containing columns: irrigated pressure drop, liquid holdup, and packing fractional wetted area. Industrial & engineering chemistry research, 40, 5140-5146, 2001.
[13] Petre, C. F., Larachi, F., Iliuta, I., & Grandjean, B. Pressure drop through structured packings: Breakdown into the contributing mechanisms by CFD modeling. Chemical Engineering Science, 58, 163-177, 2003.
[14] Larachi, F. ç., Petre, C. F., Iliuta, I., & Grandjean, B. Tailoring the pressure drop of structured packings through CFD simulations. Chemical Engineering and Processing: Process Intensification, 42, 535-541, 2003.
[15] Mahr B, Mewes D. Two-phase flow in structured packings: modeling and calculation on a macroscopic scale. AIChE J. 54:614–624, 2010.
[16] Pham, D.A., Lim, Y., Jee, H., Ahn, E., Jung, Y. Porous media Eulerian computional fluid dynamics(CFD) model of amine absorber with structured-packing for CO2 removal. Chemical Engineering Science 132, 259-270, 2015.
[17] A. Hoffmann, I. Ausner, J. U. Repke, and G. Wozny, "Fluid dynamics in multiphase distillation processes in packed towers," Computers & Chemical Engineering, vol. 29, pp. 1433-1437, 2005.
[18] Raynal, L., and A. Royon-Lebeaud. "A multi-scale approach for CFD calculations of gas–liquid flow within large size column equipped with structured packing." Chemical Engineering Science 62.24, pp. 7196-7204, 2007.
[19] Atmakidis, T., & Kenig, E. Y. Numerical analysis of mass transfer in packed-bed reactors with irregular particle arrangements. Chemical Engineering Science, 81, 77-83, 2012.
[20] Lopes, R. J., & Quinta-Ferreira, R. M. CFD modelling of multiphase flow distribution in trickle beds. Chemical Engineering Journal, 147, 342-355, 2009.
[21] Boccardo, G., Augier, F., Haroun, Y., Ferre, D., & Marchisio, D. L. Validation of a novel open-source work-flow for the simulation of packed-bed reactors. Chemical Engineering Journal, 279, 809-820, 2015.
[22] Ookawara, Shinichi, et al. "High-fidelity DEM-CFD modeling of packed bed reactors for process intensification." Proceedings of European Congress of Chemical Engineering (ECCE-6), Copenhagen. 2007.
[23] Y. Jiang, M. Khadilkar, M. Al-Dahhan, and M. Dudukovic, "CFD of multiphase flow in packed-bed reactors: I. k-Fluid modeling issues," AIChE Journal, vol. 48, pp. 701-715, 2002.
[24] A. Jafari, P. Zamankhan, S. Mousavi, and K. Pietarinen, "Modeling and CFD simulation of flow behavior and dispersivity through randomly packed bed reactors," Chemical Engineering Journal, vol. 144, pp. 476-482, 2008.
[25] A. A. Motlagh and S. Hashemabadi, "3D CFD simulation and experimental validation of particle-to-fluid heat transfer in a randomly packed bed of cylindrical particles," International Communications in Heat and Mass Transfer, vol. 35, pp. 1183-1189, 2008.
[26] H. Bai, J. r. Theuerkauf, P. A. Gillis, and P. M. Witt, "A coupled DEM and CFD simulation of flow field and pressure drop in fixed bed reactor with randomly packed catalyst particles," Industrial & Engineering Chemistry Research, vol. 48, pp. 4060-4074, 2009.
[27] Ahipo, Y., Auroux, D., Cohen, L. D., & Masmoudi, M. A hybrid scheme for contour detection and completion based on topological gradient and fast marching algorithms-Application to inpainting and segmentation. In International Conference on Scale Space and Variational Methods in Computer Vision, 386-397, 2011.
[28] Launder, B. E., & Spalding, D. The numerical computation of turbulent flows. Computer methods in applied mechanics and engineering, 3, 269-289, 1974.
[29] J. U. Brackbill, D. B. Kothe, and C. Zemach, "A continuum method for modeling surface tension," Journal of Computational Physics, vol. 100, pp. 335-354, 1993.
[30] D. A. Drew and R. T. Lahey. In Particulate Two-Phase Flow. Butterworth-Heinemann. Boston, MA509–566. 1993.
[31] Yang, Li. "CFD Modeling of Multiphase Counter-Current Flow in Packed Bed Reactor for Carbon Capture." ,2015.
[32] Ma, Y., Cao, X., Feng, X., Ma, Y., & Zou, H. 2007. Fabrication of super-hydrophobic film from PMMA with intrinsic water contact angle below 90. Polymer, 48, 7455-7460.
[33] Billet, R., & Schultes, M. Modelling of packed tower performance for rectification, absorption and desorption in the total capacity range. In the 3rd Korea-Japan Symposium, 1993.
[34] Billet, R., & Schultes, M. Prediction of mass transfer columns with dumped and arranged packings: updated summary of the calculation method of Billet and Schultes. Chemical engineering research and design, 77, 498-504, 1999.
[35]Bravo, J. L., & Fair, J. R. 1982. Generalized correlation for mass transfer in packed distillation columns. Industrial & Engineering Chemistry Process Design and Development, 21, 162-170, 1982.
[36]Onda, K., Takeuchi, H., & Okumoto, Y. Mass transfer coefficients between gas and liquid phases in packed columns. Journal of chemical engineering of Japan, 1, 56-62, 1968.
[37]Stichlmair, J., Bravo, J., & Fair, J. General model for prediction of pressure drop and capacity of countercurrent gas/liquid packed columns. Gas Separation & Purification, 3, 19-28, 1989.
[38]Dixon, A. G., Nijemeisland, M., & Stitt, E. H. Systematic mesh development for 3D CFD simulation of fixed beds: Contact points study. Computers & Chemical Engineering, 48, 135-153, 2013.