臺灣博碩士論文加值系統

　　本研究探討具渦漩效應之內混式霧化器之設計參數對霧化特性之影響，所探討的項目包括：氣體入口直徑、液體入口直徑、霧化器出口直徑與渦漩氣流之方向等參數，噴霧粒度分布以Malvern公司雷射繞射式RT-Sizer粒徑分析儀量測。
　　研究結果顯示霧化氣體之入口面積及噴嘴出口面積為控制氣體流量及噴霧粒度之重要參數。當霧化氣體之入口面積及噴嘴出口面積增加時，噴霧粒徑變小，粒子分佈範圍亦較窄。這是由於增加霧化氣體入口面積及噴嘴出口面積會增加霧化氣體流量及霧化之能量所致。究結果亦顯示，霧化氣體入口面積及噴嘴出口面積之變化為其面積比Do/Da所約制，只有面積比Ao/Aa小於1.0時，噴嘴可以產生較高之效能。這是由於在此等條件下，有利於霧化氣體在噴口位置產生加速及高速霧化之作用。另外，當液體入口面積增加，液體流量隨之增加，故知液體入口面積噴霧產生量之控制參數。而且在相同之氣液質量比下，當液體入口直徑增加，霧化器具有較佳之霧化性能。
　　旁通氣流所產生的渦漩流動方向亦為控制霧化特性之影響參數，吾人可以加入反向旁通氣流來提昇此噴嘴之霧化性能，這是由於反向旁通氣流與主氣流間之剪力作用會產生渦流，提高氣液兩相間能量與質量之傳遞現象，故顯著提昇霧化器之霧化性能。進一步分析氣液質量比對霧化效率之影響，顯示反向旁通氣流具有較高之霧化效率，故可當作一種新的霧化特性控制機制。

　This research program investigates the design parameters of the internal-mixing atomizer with swirling effects. The effects of the length scale of the orifice, gas inlet, and liquid inlet on the particle size were explored. The swirling flows generated by the bypass flow near the nozzle exit were designed as the same and opposite directions to the swirling flow of the main stream. They were designed to enhance the atomization performance. The particle size distribution of the spray was measured by Malvern RT-Sizer.
　Results show that the controlling parameters of the atomization gas flow rate and the particle size are the areas of the gas inlet and the orifice of the nozzle. By increasing the areas of the gas inlet and the orifice we can reduce the particle size and narrow down the particle size distribution. This is due to the increase in gas flow rate and hence the higher atomization energy. However, the changes of gas inlet and outlet areas are governed by a critical number of the area ratio Ao/Aa. Results show that higher atomization performance can only be achieved when the critical number is less than 1.0. Higher atomization efficiencies under this condition are due the acceleration of the atomization gas at the nozzle outlet. It is also found that the liquid flow rate increase as the inlet area of the liquid was increased under the same gas flow rates. It turns out that the spray production rate can be controlled by the inlet area of the liquid phase.
　The operation direction of the swirling flow near the nozzle exit exhibits another controlling parameter to the atomization performance. One can enhance the atomization processes when the swirling flow direction was opposite to the main stream. It is believed that the higher shear stress between the swirling flows under opposite flow directions enhances the transport processes between the gas and liquid phases. This in turn results in the reduction of the particle size of the spray. The dependence of the atomization efficiency to GLR demonstrates the existence of such an atomization mechanism.

摘要
英文摘要
誌謝
目錄 Ⅰ
表目錄 Ⅲ
圖目錄 Ⅳ
符號說明 Ⅸ

第一章 緒論 1
1-1 簡介 1
1-2 文獻回顧 2
1-2-1 液體碎化過程 2
1-2-2 噴霧流場中之空氣動力現象 5
1-2-3 雙流體式霧化器 6
1-3 研究動機 10

第二章 實驗設備及儀器 12
2-1 實驗設備 12
2-1-1 霧化器測試台架 12
2-1-2 液體供應系統 12
2-1-3 噴嘴所需高壓氣體供應系統 13
2-1-4 抽氣整流系統 13
2-1-5 霧化裝置 13
2-2 量測儀器 14
2-2-1 RT-Sizer粒徑分析儀 14
2-3主要量測參數 15

第三章 實驗步驟及方法 18
3-1 實驗量測條件 18
3-2 流量的量測 18
3-3 RT-Sizer粒徑分析儀的量測 19
3-4 數據取樣與分析 20

第四章 結果與討論 21
4-1 入氣口直徑對霧化特性之影響 21
4-1-1入氣口直徑對流量之影響 21
4-1-2入氣口直徑對氣液質量比之影響 22
4-1-3入氣口直徑對噴霧粒徑之影響 23
4-1-4入氣口直徑對霧化效率之影響 24
4-2霧化器出口直徑對霧化特性之影響 25
4-2-1霧化器出口直徑對流量之影響 26
4-2-2霧化器出口直徑對氣液質量比之影響 27
4-2-3霧化器出口直徑對噴霧粒徑之影響 27
4-2-4霧化器出口直徑對霧化效率之影響 29
4-3液體入口直徑對霧化特性之影響 30
4-3-1液體入口直徑對流量之影響 30
4-3-2液體入口直徑對氣液質量比之影響 31
4-3-3液體入口直徑對噴霧粒徑之影響 31
4-3-4液體入口直徑對霧化效率之影響 33
4-4正向、反向旁通氣流與無旁通氣流霧化器間之比較 35
4-4-1正向、反向旁通氣流與無旁通氣流配置對流量之影響 35
4-4-2正向、反向旁通氣流與無旁通氣流配置對氣液質量比之影響 37
4-4-3正向、反向旁通氣流與無旁通氣流配置對噴霧粒徑之影響 38
4-4-4正向、反向旁通氣流與無旁通氣流配置對霧化效率之影響 40

第五章 結論 43

參考文獻 45

自述 93

1. A. H. Lefebvre, “Gas Turbine Combustion,” Chapter10, Hemisphere Publishing Corporation, New York, 1983.

2. A. H. Lefebvre, “Atomization and Sprays,” Hemisphere Publishing Corporation, New York, 1989.

3. R. A. Castleman Jr., “The Mechanism of the Atomization of Liquids,” Burean of Standards Journal of Research, Vol.6, pp.369-376, 1930.

4. N. Dombrowski and W. R. Johns, ”The Aerodynamic Instability and Disintegration of Viscous Liquid Sheets,” Chem. Eng. Sci., Vol.18, pp.203-214, 1963.

5. B. E. Stapper, W. A. Sowa and G. S. Samuelsen, “An Experimental Study of the Effects of Liquid Properties on the Breakup of a Two-dimensional Liquid Sheet,” ASME, Journal of Engineering for Gas Turbines and Power, Vol.114, pp.39-45, 1992.

6. R. P. Fraser, “Liquid Fuel Atomization,” Sixth Symposium (International) on Combustion, Rein-hold, New York, pp.687-701, 1957.

7. M.C. Butler Ellis and C.R. Tuck, “How Adjuvants Influence Spray Formation with Different Hydraulic Nozzle, “ Crop Protection, Vol.18, pp.101-109, 1999.

8. M.C. Butler Ellis, C.R. Tuck and P,C.H. Miller, “How Surface Tension of Surfactant Solution Influences the Characteristics of Sprays Produced by Hydraulic Nozzle Used for Pesticide Application,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 180, pp.267-276, 2001.

9. G. D. Crapper, N. Dombrowski, W. P. Jepson and G. A. D. Pyott, ”A Note on the Growth of Kelvin-Helmholtz Waves on Thin Liquid Sheets,” J. Fluid Mech., Vol.57, part 4, pp.671-672, 1973.

10. H. C. Simmons, “The Atomization of Liquid, Principles and Methods,” Parker Hannifin Report No.8, pp.61-92, 1982.

11. C.H. Lee and R.D. Retiz, “An Experimental Study of the Effect of Gas Density on the Distortion and Breakup Mechanism of Drops in High Speed Gas Stream,” International Journal of Multiphase Flow., Vol.26, pp.299-244, 2000.

12. 許耀仁, “氣衝式平面噴嘴液膜霧化特性之研究,” 國立成功大學碩士論文, 1993.

13. J.H. Chin, D. Nickolaus and A.H. Lefebvre, “Influence of Distance on the Spray Characteristics of Pressure-Swirl Atomizer,” ASME, Journal of Engineering for Gas Turbines and Power, Vol.108, pp.219-224,1986.

14. 趙金榮, “相差都卜勒粒子分析儀應用於燃油噴嘴特性之研究”, 國立成功大學碩士論文, 1988.

15. 蔡清洲, “漩渦噴流中氣液兩相交互作用實驗分析,” 國立成功大學碩士論文, 1989.

16. 洪嘉宏, “中空錐形噴霧中連續相及離散相之動力特性研究,” 國立成功大學博士論文, 1991.

17. 楊坤和, “研究型氣助式噴霧特性研究,” 國立成功大學碩士論文, 1992.

18. 賴維祥, “噴霧發展過程中粒子之輸送現象及其紊流條調制之研究,” 國立成功大學博士論文, 1995.

19. 徐明生, “雙流體式平面噴嘴霧化特性之研究,” 國立成功大學碩士論文, 1995.

20. A. A. Rizkalla and A. H. Lefebvre, “Influence of Liquid Properties on Airblast Atomizer Spray Characteristics,” J. Eng. Power, pp.173-179, April 1975.

21. A. A. Rizkalla and A. H. Lefebvre, “The Influence of Air and Liquid Properties on Airblast Atomization,” J. Fluids Eng., Vol.97, pp.316-320, 1975.

22. N. K. Rizk and A. H. Lefebvre, “Influence of Atomizer Design Feature on Mean Drop Size,” AIAA Journal, Vol.21, No.8, pp.1139-1142, 1983.

23. J. Beck, A. H. Lefebvre and T. Koblish, “Airblast Atomization at Conditions of Low Air Velocity,” Paper No, AIAA, 89-0217, 1989.

24. J. E. Beck, A. H. Lefebvre and T. R. Koblish, “Liquid Sheet Disintegration by Impinging Air Streams,” Atomization and Sprays, Vol.1, No.2, pp.155-170, 1991.

25. J. E. Beck and A. H. Lefebvre, “Airblast Atomization at Conditions of Low Air Velocity,” J. Propulsion, Vol.7, No.2, March-April 1991.

26. M. Aligner and S. Witting, “Swirl and Counterswirl Effects in Prefilming Airblast Atomization,” Trans. ASME, J. Eng. Power, Vol.102, pp.706-710, 1980.

27. T. Sattlemayer and S. Witting, “Internal Flow Effects in Prefilming Airblast Atomizers Mechanisms of Atomization and Droplet Spectra,” ASME Journal of Engineering for Gas Turbine and Power, Vol.108, pp.465-472, 1986.

28. C. Press, A. K. Gupta and H. G. Semerjian, “Aerodynamic Effects on Fuel Spray Characteristics: Air-assist Atomizer,” HTD, Vol.104, pp.111-119, 1988.

29. J. D. Whitlow and A. H. Lefebvre, “Effervescent Atomizer Operation and Spray Characteristics,” Atomization and Spray, Vol.3, pp.137-155, 1993.

30. 王承光, “氣助式及氣衝式平面噴嘴中霧化空氣對噴霧特性之研究,” 國立成功大學碩士論文, 1996.

31. S. K. Chen and A. H. Lefebvre, “Spray Cone Angles of Effervescent Atomizers,” Atomization and Spray, Vol.4, pp.291-301, 1994.

32. S. D. Sovani, P. E. Sojka and A. H. Lefebvre, “Effervescent Atomization,” Progress in Energy and Combustion Science, Vol.27 pp.483-521, 2001.

33. M. V. Panchagnula and P. E. Sojka, “Spatial Droplet Velocity and Size Profiles in Effervescent Atomizer-Produced Sprays,” Fuel, Vol.78 pp.729-741, 1999.

34. B. Leroux, O. Delabroy and F. Lacas, “Influence of Superpulsating Mode on Atomization Properties in Coaxial Air-assisted Atomizers,” Eighth International Conference on Liquid Atomization and Spray Systems, July 2000.

35. A. Kufferath, B. Wende and W. Leuckel, ”Influence of Liquid Flow Conditions on Spray Characteristics of Internal-Mixing Twin-Fluid Atomizers,” International Journal of Heat and Fluid Flow, Vol.20 pp.513-519, 1999.

36. L. J. Guo, G. J. Li, B. Chen, X. J. Chen, D. D. Papailiou and Th. Panidis, “Study on Gas-Liquid Two-Phase Spraying Characteristics of Nozzles for the Humidification of Smoke,” Experimental Thermal and Fluid Science, Vol.26 pp.715-722, 2002.

37. 林彰廷, “多噴頭效應在氣助式噴嘴中之霧化特性研究,” 國立成功大學碩士論文, 2003.

38. 曾瑛仁, “具奇點結構之內混式霧化器噴霧特性研究,” 2004中國航空太空學會年會暨航太學會/民航學會聯合學術研討會, 台灣,台中,December 2004