本研究旨在探討在不同氣體流量條件下，使用薄膜式散氣盤進行曝氣時所形成的兩相流動行為及其對溶氧（DO）變化的影響。實驗設計採用直徑26.8公分的薄膜式散氣盤，置於底部為60 x 60公分的方形水槽內，曝氣密度為11%。實驗包括兩種風量條件：10 L/min和45 L/min，並觀察氣泡柱的形成和兩相流流動形態變化，使用溶氧儀測量水體中不同位置的溶氧濃度變化。
數值模擬方面，採用ANSYS Fluent 2021軟體，測試了標準k-ϵ模型、RNG k-ϵ模型及Realize k-ϵ模型等紊流模型，並比較了Tomiyama模型、Schiller-Naumann模型和Grace模型等不同阻力模型的模擬結果與實驗結果之間的差異。結果顯示，在氣占比和速度分布方面，三種紊流模型的模擬結果無顯著差異，因此選擇標準k-ϵ模型進行後續模擬。在阻力模型方面，雖然Schiller-Naumann、Grace和Tomiyama三種模型無顯著差異，但Tomiyama模型模擬的氣泡分率分布範圍與實驗較為吻合，因此選用Tomiyama模型進行分析。
實驗結果顯示，不同風量條件下的氣泡運動和溶氧變化具有顯著差異。在10 L/min風量條件下，氣泡尺寸介於0.70到2.68 mm且粒徑分布近似常態分布，氧傳係數k_L a為0.015-0.017 1/min；在45 L/min風量條件下，氣泡尺寸介於0.71到3.03 mm，水體擾動明顯增強且k_L a提升至0.035-0.039 1/min。氣泡的長寬比小於1 mm時約為0.7-0.8，大於2 mm時落在0.5-0.6，顯示其形狀並非理想球體，因而更適合使用考量氣泡形狀之阻力模型。
數值模擬結果顯示，氣泡速度在數值和實驗結果中相當一致。在45 L/min曝氣條件下，無氣泡區域之水體流速不論數值或實驗結果都小於0.1 m/s。實驗中，水槽高0.3 m處水體有類似向氣泡柱方向補注的情況，而在實際觀察中，水槽0.2到0.4 m處可見漩渦或水平擾動現象，此說明數值模擬在了解氣泡柱整體流場方面的有效性。
研究顯示，適當的紊流模型和阻力模型選擇對模擬薄膜式散氣盤的兩相流特性至關重要。實驗與數值模擬結果的一致性為曝氣系統的設計和優化提供了可靠的參考依據。未來的研究應進一步探討不同曝氣條件下的氣泡流特性及溶氧變化，以提升污水處理系統的效能。

This study aims to investigate the characteristics of two-phase flow and dissolved oxy-gen (DO) changes formed by aeration using a membrane diffuser under different gas flow conditions. The experimental setup uses a 26.8 cm diameter membrane diffuser placed in a square tank with a bottom dimension of 60 x 60 cm and an aeration density of 11%. The experiments include two airflow conditions (10 L/min and 45 L/min) to observe the formation of bubble plumes and changes in two-phase flow patterns, while measuring DO concentrations at different locations in the water using a dissolved oxy-gen meter. Numerical simulations were conducted using ANSYS Fluent 2021 software, testing standard k-ε, RNG k-ε, and Realizable k-ε turbulence models, and comparing the results of Tomiyama, Schiller-Naumann, and Grace drag models with experimental data. The results indicate significant differences in bubble movement and DO changes under different airflow conditions. Under the 10 L/min airflow condition, bubble sizes range from 0.70 to 2.68 mm with a near-normal distribution and an oxygen transfer co¬efficient (k_L a) of 0.015-0.017 1/min. Under the 45 L/min condition, bubble sizes range from 0.71 to 3.03 mm, water disturbances are significantly enhanced, and k_L a increases to 0.035-0.039 1/min. The numerical simulation results are consistent with experimental data, confirming the effectiveness of numerical simulations in studying gas-liquid two-phase flow. The study provides valuable references for optimizing aeration system de¬sign and improving aeration efficiency.

1. Al Ba'ba'a, H. B. and R. S. Amano. “A study of optimum aeration efficiency of a lab‐scale air‐diffused system.” Water and Environment Journal 31(3): 432-439. 2017.
2. ANSYS.Inc . "ANSYS Fluent Theory Guide." 2021.
3. ANSYS.Inc . "ANSYS Meshing Users Guide." 2021.
4. Ashley, K. I., Mavinic, D. S., & Hall, K. J. “Bench-scale study of oxygen trans-fer in coarse bubble diffused aeration.” Water Research, 26(10), 1289-1295. 1992.
5. Bhuyar, L. B., Thakre, S. B., & Ingole, N. W. “Design characteristics of curved blade aerator wrt aeration efficiency and overall oxygen transfer coefficient and comparison with CFD modeling.” International Journal of Engineering, Sci-ence and Technology 1(1), 1-15. 2009.
6. Bishop, R. F.. "Thermo-fluid Dynamic Theory of Two-Phase Flow." Physics Bulletin 26(12): 544-544. 1975.
7. Borchers, O., C. Busch, A. Sokolichin and G. Eigenberger. "Applicability of the standard k–ε turbulence model to the dynamic simulation of bubble columns. Part II:: Comparison of detailed experiments and flow simulations." Chemical Engineering Science 54: 5927-5935. 1999.
8. Cartland Glover, G., S. Generalis and N. Thomas. "CFD and Bubble Column Reactors: Simulation and Experiment." Chemical Papers- Slovak Academy of Sciences 54: 361. 2000
9. Cheung, S. C. P., G. H. Yeoh and J. Y. Tu. "On the numerical study of isothermal vertical bubbly flow using two population balance approaches." Chemical Engineering Science 62(17): 4659-4674. 2007.
10. Clift, R., J. R. Grace and M. E. Weber. "Bubbles, drops, and particles." Dry. Technol. 11: 263-264. 1978.
11. Cockx, A., Do-Quang, Z., Audic, J. M., Liné, A., & Roustan, M.. Global and lo-cal mass transfer coefficients in waste water treatment process by computation-al fluid dynamics. Chemical Engineering and Processing: Process Intensifica-tion, 40(2), 187-194. 2001.
12. Deckwer, W. D. and A. Schumpe. "Improved tools for bubble column reactor design and scale-up." Chemical Engineering Science 48: 889-911. 1993.
13. Doran, P. M.. Chapter 10 - Mass Transfer. Bioprocess Engineering Principles (Second Edition). P. M. Doran. London, Academic Press: 379-444. 2013
14. Drew, D. A.. "Mathematical Modeling of Two-Phase Flow." Annual Review of Fluid Mechanics 15(1): 261-291. 1983
15. Ekambara, K. and M. T. Dhotre. "CFD simulation of bubble column." Nuclear Engineering and Design 240(5): 963-969. 2010
16. Fayolle, Y., Cockx, A., Gillot, S., Roustan, M., & Héduit, A.. Oxygen transfer prediction in aeration tanks using CFD. Chemical Engineering Science, 62(24), 7163-7171. 2007
17. Forret, A., J. M. Schweitzer, T. Gauthier, R. Krishna and D. Schweich. "Influence of scale on the hydrodynamics of bubble column reactors: An experimental study in columns of 0.1, 0.4 and 1 m diameters." Chemical Engineering Science - CHEM ENG SCI 58: 719-724. 2003
18. Gillot, S., S. Capela-Marsal, M. Roustan and A. Heduit. "Predicting oxygen transfer of fine bubble diffused aeration systems--model issued from dimensional analysis." Water Res 39(7): 1379-1387. 2005
19. Gimbun, J., C. D. Rielly and Z. K. Nagy. "Modelling of mass transfer in gas–liquid stirred tanks agitated by Rushton turbine and CD-6 impeller: A scale-up study." Chemical Engineering Research and Design 87(4): 437-451. 2009
20. Glover, G. C., Printemps, C., Essemiani, K., & Meinhold, J.. Modelling of wastewater treatment plants–how far shall we go with sophisticated modelling tools?. Water science and Technology, 53(3), 79-89. 2006
21. Gresch, M., Armbruster, M., Braun, D., & Gujer, W.. Effects of aeration patterns on the flow field in wastewater aeration tanks. Water research, 45(2), 810-818. 2011
22. Karpinska, A. M., & Bridgeman, J.. CFD-aided modelling of activated sludge systems–A critical review. Water research, 88, 861-879. 2016
23. Khuntia, S., S. K. Majumder and P. Ghosh. "Microbubble-aided water and wastewater purification: A review." Reviews in Chemical Engineering 28(4-6): 191-221. 2012
24. Koynov, A., G. Tryggvason and J. G. Khinast. "Characterization of the localized hydrodynamic shear forces and dissolved oxygen distribution in sparged bioreactors." Biotechnology and Bioengineering 97(2): 317-331. 2007
25. Launder, B. E. and D. B. Spalding. "The numerical computation of turbulent flows." Computer Methods in Applied Mechanics and Engineering 3(2): 269-289. 1974
26. Laupsien, D., A. Cockx and A. Line (2017). "Bubble Plume Oscillations in Viscous Fluids." Chemical Engineering & Technology 40(8): 1484-1493. 2017
27. Le Moullec, Y., Potier, O., Gentric, C., & Leclerc, J. P. (2011). Activated sludge pilot plant: comparison between experimental and predicted concentration pro-files using three different modelling approaches. Water Research, 45(10), 3085-3097. 2011
28. Lee, S. (2018). "Evaluation of oxygen transfer from bubble and free surface in bubble reactors using CFD." Chemical Engineering Research and Design 140: 251-260. 2018
29. Lewis, W. K. and W. G. Whitman (1924). "Principles of Gas Absorption." Industrial & Engineering Chemistry 16(12): 1215-1220. 1924
30. Liu, Y., E. R. Upchurch and E. M. Ozbayoglu (2021). "Experimental Study of Single Taylor Bubble Rising in Stagnant and Downward Flowing Non-Newtonian Fluids in Inclined Pipes." Energies 14(3). 2021
31. McClure, D. D., C. Wang, J. M. Kavanagh, D. F. Fletcher and G. W. Barton (2016). "Experimental investigation into the impact of sparger design on bubble columns at high superficial velocities." Chemical Engineering Research and Design 106: 205-213. 2016
32. Merchuk, J. C. and S. Ben-Zvi (1992). "A novel approach to the correlation of mass transfer rates in bubble columns with non- Newtonian liquids." Chemical Engineering Science 47(13): 3517-3523. 1992
33. Mudde, R. F. (2005). "Gravity-driven bubbly flows." Annual Review of Fluid Mechanics, 37 37. 2005
34. Murai, Y., Y. Oishi, Y. Takeda and F. Yamamoto (2006). Turbulent shear stress profiles in a bubbly channel flow assessed by particle tracking velocimetry. Experiments in Fluids. 2006
35. NORTEK.Inc (2018). "The Comprehensive Manual for Velocimeters." 2018
36. Pittoors, E., Y. Guo and S. W. H. Van Hulle (2014). "Oxygen transfer model development based on activated sludge and clean water in diffused aerated cylindrical tanks." Chemical Engineering Journal 243: 51-59. 2014
37. Portela, A. M. K. (2014). New design tools for activated sludge process (Doc-toral dissertation, Universidade do Porto (Portugal)). 2014
38. Prakash, R., S. Kumar Majumder and A. Singh (2020). "Bubble size distribution and specific bubble interfacial area in two–phase microstructured dense bubbling bed." Chemical Engineering Research and Design 156: 108-130. 2020
39. Raffel, M., C. Willert, S. Wereley and J. Kompenhans (2007). Particle Image Velocimetry: A Practical Guide. 2007
40. Raffel, M., F. Scarano, C. E. Willert, C. J. Kähler, S. T. Wereley and J. Kompenhans (2018). "Particle Image Velocimetry." 2018
41. Ranade, V. V. (1992). "Flow in bubble columns: some numerical experiments." Chemical Engineering Science 47(8): 1857-1869. 1992
42. Ranade, V. V. (1997). "An efficient computational model for simulating flow in stirred vessels: a case of Rushton turbine." Chemical Engineering Science 52(24): 4473-4484. 1997.
43. Rehman, U., Audenaert, W., Amerlinck, Y., Maere, T., Arnaldos, M., & Nopens, I.. How well-mixed is well mixed? Hydrodynamic-biokinetic model integration in an aerated tank of a full-scale water resource recovery facility. Water Science and Technology, 76(8), 1950-1965. 2017.
44. Riboux, G., F. Risso and D. Legendre. "Experimental characterization of the agitation generated by bubbles rising at high Reynolds number." Journal of Fluid Mechanics 643: 509-539. 2009.
45. Sánchez, F., Rey, H., Viedma, A., Nicolás-Pérez, F., Kaiser, A. S., & Martínez, M.. CFD simulation of fluid dynamic and biokinetic processes within activated sludge reactors under intermittent aeration regime. Water research, 139, 47-57. 2018.
46. Schierholz, E. L., J. S. Gulliver, S. C. Wilhelms and H. E. Henneman. "Gas transfer from air diffusers." Water Res 40(5): 1018-1026. 2006.
47. Shah, Y. T., B. G. Kelkar, S. P. Godbole and W.-D. Deckwer. "Design parameters estimations for bubble column reactors." AIChE Journal 28(3): 353-379. 1982.
48. Shih, T.-H., W. W. Liou, A. Shabbir, Z. Yang and J. Zhu. "A new k-ϵ eddy viscosity model for high reynolds number turbulent flows." Computers & Fluids 24(3): 227-238. 1995.
49. Sokolichin, A. and G. Eigenberger. "Applicability of the standard k–ε turbulence model to the dynamic simulation of bubble columns: Part I. Detailed numerical simulations." Chemical Engineering Science 54: 2273-2284. 1999.
50. Stenstrom, M. K., H. R. Vazirinejad and A. S. Ng. "Economic-Evaluation of Upgrading Aeration Systems." Journal Water Pollution Control Federation 56(1): 20-26. 1984.
51. Taborda, M. A. and M. Sommerfeld. "Reactive LES-Euler/Lagrange modelling of bubble columns considering effects of bubble dynamics." Chemical Engineering Journal 407. 2021.
52. Temesgen, T., Bui, T. T., Han, M., Kim, T. I., & Park, H.. Micro and nanobubble technologies as a new horizon for water-treatment techniques: A review. Ad-vances in colloid and interface science, 246, 40-51. 2017.
53. Tomiyama, A., I. Kataoka, I. Zun and T. Sakaguchi. "Drag Coefficients of Single Bubbles under Normal and Micro Gravity Conditions." JSME International Journal Series B 41(2): 472-479. 1998.
54. Uby, L.. "Next steps in clean water oxygen transfer testing - A critical review of current standards." Water Res 157: 415-434. 2019.
55. USEPA.. Design Manual–Fine Pore Aeration Systems. Cincinnati, Ohio, United States. 1989.
56. Versteeg, H. K. and W. Malalasekera. "An Introduction to Computational Fluid Dyanmics: The Finite Volume Method, 2nd ed.". 2007.
57. WEF & ASCE Design municipal wastewater Plants , 4th Edition , 1998
58. Westerweel, J., G. E. Elsinga and R. J. Adrian. "Particle Image Velocimetry for Complex and Turbulent Flows." Annual Review of Fluid Mechanics 45(1): 409-436. 2013.
59. Xu, N., Fan, L., Pang, H., & Shi, H.. Feasibility study and CFD‐aided design for a new type oxidation ditch based on airlift circulation. The Canadian Journal of Chemical Engineering, 88(5), 728-741. 2010.
60. Yakhot, V., S. A. Orszag, S. Thangam, T. B. Gatski and C. G. Speziale. "Development of turbulence models for shear flows by a double expansion technique." Physics of Fluids A: Fluid Dynamics 4(7): 1510-1520. 1992.
61. Yeoh, G. H., C. P. Cheung and J. Tu. Multiphase flow analysis using population balance modeling: bubbles, drops and particles, Butterworth-Heinemann. 2013.
62. 內政部營建署，污水處理廠生物處理單元微生物族群處理效能與薄膜細泡式散氣設備曝氣效率及檢測驗證應用先期評估計畫，期末成果報告，112年7月，2023。
63. 內政部營建署，污水處理廠重要設備規範(上冊)110年版，2021。
64. 內政部營建署，污水處理廠重要設備規範解說(下)增修版，2022。
65. 唐家鵬，FLUENT+14.0超级学习手册，人民郵電出版社，中國， 2013。