臺灣博碩士論文加值系統

本研究的主題在觀察十二烷液滴於高溫環境場燃燒飛行過程的火焰特性，與撞擊高溫熱石英平板的擴張與碎裂行為。在本實驗中，加熱平板被放置在距進口端三種不同的撞擊位置，其撞擊的熱平板板溫分別為720、509與407 (oC)；液滴直徑介於400到1400(μm)之間；液滴韋伯數介於150到1800之間。本研究中發現，十二烷液滴被點燃後，；當其強制對流項與自然對流項平衡時，火焰形成球對稱火焰。在靠近石英平板的過程中，火焰會逐漸地向液滴後方移動；液滴撞擊石英平板瞬間，其火焰位於液滴後方。在石英板上液膜的擴張型態可分為：碟狀液膜擴張、皇冠狀液膜擴張。液滴碎裂型態則可分為：不均勻碎裂、均勻碎裂。液滴碎裂型態與韋伯數相關，較大的韋伯數能產生均勻碎裂。

This investigation explores the flame transition process and impinging phenomenon of a burning dodecane drop in a convective high-temperature gaseous environment. In the experiment, the plate was inserted at three different positions in the high-temperature flow. And the temperature of the impinging plate was 720, 509 or 407 (oC). The drop diameter ranged from 400 to 1400 μm. Weber number ranged from 150 to 1800. A stream of burning dodecane drops moved with the high-temperature gaseous flow and impinged onto the plate. By changing the drop diameter, the Weber number was varied. The drop was ignited after a certain distance into the combustion chamber. When the forced convection term equaled the natural convection term, the flame became a spherical flame. As the drop approached the heated plate, the flame moved toward the trailing side of the drop because the drop was accelerated by gravity. The gas flow slowed down as the drop approached the plate because of the stagnation-point flow near the plate. The drop impinged the quartz plate with the flame completely leaving the drop. After impact, the drop experienced expansion and contraction to disintegrate. There were two different expansion types, namely crown film expansion and plate film expansion. And there were two disintegration types, namely uniform disintegration and non-uniform disintegration depending on the Weber number (We).

總目錄 ••••••••••••••••••••••••••••••••••••••••••••••• I
表目錄 ••••••••••••••••••••••••••••••••••••••••••••••• IV
圖目錄 ••••••••••••••••••••••••••••••••••••••••••••••• V
符號說明•••••••••••••••••••••••••••••••••••••••••••••• VII
第一章 緒論••••••••••••••••••••••••••••••••••••••••••• 1
1-1 前言••••••••••••••••••••••••••••••••••••••• 1
1-2 文獻回顧 •••••••••••••••••••••••••••••••••• 2
1-3 研究目的••••••••••••••••••••••••••••••••••• 5
第二章 實驗設備與研究方法 ••••••••••••••••••••••••••• 7
2-1 液滴產生系統 •••••••••••••••••••••••••••••• 7
2-2 燃燒室系統••••••••••••••••••••••••••••••••• 7
2-3 影像擷取系統••••••••••••••••••••••••••••••• 8
2-4 計算模擬方法••••••••••••••••••••••••••••••• 8
2-4-1 物理模型••••••••••••••••••••••••••••• 10
2-4-2 基本假設••••••••••••••••••••••••••••• 10
2-4-3 統御方程式••••••••••••••••••••••••••• 11
2-4-4 邊界條件••••••••••••••••••••••••••••• 12
2-4-5 網格建置 •••••••••••••••••••••••••••• 12
2-4-6 計算流體力學簡介••••••••••••••••••••• 14
2-4-7 FLUENT簡介 •••••••••••••••••••••••• 15
2-4-8 離散法則 •••••••••••••••••••••••••••• 15
2-4-9 空間離散••••••••••••••••••••••••••••• 16
2-4-10 壓力基準求解器 •••••••••••••••••••••• 18
2-4-11 計算方式••••••••••••••••••••••••••••• 18
2-4-12 動網格生成方式••••••••••••••••••••••• 20
2-4-13 運動模型••••••••••••••••••••••••••••• 20
第三章 燃燒液滴撞擊熱板的火焰轉換分析•••••••••••••••• 24
3-1 火焰轉換特性分析••••••••••••••••••••••••••• 26
3-2 韋伯數對於火焰之影響••••••••••••••••••••••• 31
3-3 氧濃度對於火焰之影響••••••••••••••••••••••• 33
3-4 結論••••••••••••••••••••••••••••••••••••••• 33
第四章 燃燒液滴撞擊熱板的撞擊分析•••••••••••••••••••• 35
4-1 板溫720oC之燃燒液滴的撞擊現象分析•••••••••• 36
4-2 板溫509oC之燃燒液滴的撞擊現象分析•••••••••• 37
4-3 板溫407oC之燃燒液滴的撞擊現象分析•••••••••• 38
4-4 結果與討論••••••••••••••••••••••••••••••••• 38
4-5 結論••••••••••••••••••••••••••••••••••••••• 40
第五章 總結•••••••••••••••••••••••••••••••••••••••••• 42
第六章 參考文獻•••••••••••••••••••••••••••••••••••••• 44
第七章 圖表•••••••••••••••••••••••••••••••••••••••••• 48

1.Rein, M., “Phenomena of liquid drop impact on solid and liquid surfaces, Fluid Dynamics Research, Vol. 12, p. 61-93, 1993.
2.Šikalo, Š. and E. Ganić, “Phenomena of droplet–surface interactions, Exp. Them Fluid Sci., Vol. 31, p. 97-110, 2006.
3.Rayleigh, L., “The theory of sound, 2 vols, London, I, Vol. 877, 1945.
4.Pawloski, L., “The Science and Engineering of Thermal Spray Coatings, Wisley, 1995.
5.Dykhuizen, R., “Review of impact and solidification of molten thermal spray droplets, J. Thermophys Heat Transfer, Vol. 3, p. 351-361, 1994.
6.Roisman, I.V., K. Horvat, and C. Tropea, “Spray impact: Rim transverse instability initiating fingering and splash, and description of a secondary spray, Phys. Fluids, Vol. 18, p. 102104, 2006.
7.Sivakumar, D. and C. Tropea, “Splashing impact of a spray onto a liquid film, Phys. Fluids, Vol. 14, p. L85, 2002.
8.Mudawar, I. and K. Estes, “Optimizing and predicting CHF in spray cooling of a square surface, Journal of Heat Transfer, Vol. 118, p. 672, 1996.
9.Pasandideh-Fard, M., et al., “Cooling effectiveness of a water drop impinging on a hot surface, International journal of heat and fluid flow, Vol. 22, p. 201-210, 2001.
10.Post, S.L. and J. Abraham, “Modeling the outcome of drop–drop collisions in Diesel sprays, International Journal of Multiphase Flow, Vol. 28, p. 997-1019, 2002.
11.Cossali, G., A. Coghe, and M. Marengo, “The impact of a single drop on a wetted solid surface, Exp. Fluids, Vol. 22, p. 463-472, 1997.
12.Rioboo, R., et al., “Experimental investigation of splash and crown formation during single drop impact on wetted surfaces, Exp. Fluids, Vol. 35, p. 648-652, 2003.
13.Li, H., et al., “Effects of surface conditions on the flattening behavior of plasma sprayed Cu splats, Surface and Coatings Technology, Vol. 200, p. 5435-5446, 2006.
14.Dewitte, J., P. Berthoumieu, and G. Lavergne, “An Experimental Study of Droplet–Hot Wall Interactions and a Survey of the Splashing Regime, 2005.
15.Ghafouri-Azar, R., et al., “Interactions between molten metal droplets impinging on a solid surface, International journal of heat and mass transfer, Vol. 46, p. 1395-1407, 2003.
16.Karl, A. and A. Frohn, “Experimental investigation of interaction processes between droplets and hot walls, Phys. Fluids, Vol. 12, p. 785, 2000.
17.Miklavcic, S., R.G. Horn, and D.J. Bachmann, “Colloidal interaction between a rigid solid and a fluid drop, The Journal of Physical Chemistry, Vol. 99, p. 16357-16364, 1995.
18.Thiel, P.A. and T.E. Madey, “The interaction of water with solid surfaces: fundamental aspects, Surface Science Reports, Vol. 7, p. 211-385, 1987.
19.Bertola, V., “Drop impact on a hot surface: effect of a polymer additive, Exp. Fluids, Vol. 37, p. 653-664, 2004.
20.Range, K. and F. Feuillebois, “Influence of surface roughness on liquid drop impact, Journal of Colloid and interface Science, Vol. 203, p. 16-30, 1998.
21.Sobolev, V.V., J.M. Guilemany, and J. Therm, “Spray Technol, Wiley, 1999.
22.Coddet, C., et al., “Spray Technol, Wiley, 1999.
23.Wachters, L., et al., “The heat transfer from a hot wall to impinging mist droplets in the spheroidal state, Chemical Engineering Science, Vol. 21, p. 1231-1238, 1966.
24.Ueda, T., T. Enomoto, and M. Kanetsuki, “Heat transfer characteristics and dynamic behavior of saturated droplets impinging on a heated vertical surface, Bulletin of JSME, Vol. 22, p. 724-732, 1979.
25.Makino, K. and I. Michiyoshi, “The behavior of a water droplet on heated surfaces, International journal of heat and mass transfer, Vol. 27, p. 781-791, 1984.
26.Akao, F., et al., “Deformation Behaviours of a Liquid Droplet Impinging onto Hot Metal Surface, Trans. Iron Steel Inst. Jpn., Vol. 20, p. 737-743, 1980.
27.Chandra, S. and C. Avedisian, “On the collision of a droplet with a solid surface, Proceedings: Mathematical and Physical Sciences, Vol., p. 13-41, 1991.
28.Chandra, S. and C. Avedisian, “Observations of droplet impingement on a ceramic porous surface, International journal of heat and mass transfer, Vol. 35, p. 2377-2388, 1992.
29.Anders, K., N. Roth, and A. Frohn, “The velocity change of ethanol droplets during collision with a wall analysed by image processing, Exp. Fluids, Vol. 15, p. 91-96, 1993.
30.Karl, A., K. Anders, and A. Frohn, “Experimental investigation of droplet deformation during wall collisions by image analysis, ASME, New York, NY,(USA). Vol. 172, p. 135-141, 1993.
31.Jiang, Y., A. Umemura, and C. Law, “An experimental investigation on the collision behaviour of hydrocarbon droplets, Journal of Fluid Mechanics, Vol. 234, p. 171-190, 1992.
32.Hatta, N., et al., “Collision dynamics of a water droplet impinging on a rigid surface above the Leidenfrost temperature, ISIJ international, Vol. 35, p. 50-55, 1995.
33.Fujimoto, H. and N. Hatta, “Deformation and rebounding processes of a water droplet impinging on a flat surface above Leidenfrost temperature, Journal of fluids engineering, Vol. 118, p. 142, 1996.
34.Yao, S.C. and K.Y. Cai, “The dynamics and Leidenfrost temperature of drops impacting on a hot surface at small angles, Exp. Them Fluid Sci., Vol. 1, p. 363-371, 1988.
35.Kincaid, D., K. Solomon, and J. Oliphant, “Drop size distributions for irrigation sprinklers, Transactions of the ASAE, Vol. 39, p. 839-845, 1996.
36.Fedorchenko, A.I., A.B. Wang, and Y.H. Wang, “Effect of capillary and viscous forces on spreading of a liquid drop impinging on a solid surface, Phys. Fluids, Vol. 17, p. 093104, 2005.
37.Ko, Y. and S. Chung, “An experiment on the breakup of impinging droplets on a hot surface, Exp. Fluids, Vol. 21, p. 118-123, 1996.
38.Kang, B. and D. Lee, “On the dynamic behavior of a liquid droplet impacting upon an inclined heated surface, Exp. Fluids, Vol. 29, p. 380-387, 2000.
39.Bernardin, J.D., C.J. Stebbins, and I. Mudawar, “Mapping of impact and heat transfer regimes of water drops impinging on a polished surface, International journal of heat and mass transfer, Vol. 40, p. 247-267, 1997.
40.Bernardin, J.D., C.J. Stebbins, and I. Mudawar, “Effects of surface roughness on water droplet impact history and heat transfer regimes, International journal of heat and mass transfer, Vol. 40, p. 73-88, 1996.
41.Chaves, H., A.M. Kubitzek, and F. Obermeier, “Dynamic processes occurring during the spreading of thin liquid films produced by drop impact on hot walls, International journal of heat and fluid flow, Vol. 20, p. 470-476, 1999.
42.施德壽和吳澤松, “生質柴油液滴撞擊不同陶瓷鍍膜材質之表面動態變化探討, 中華民國燃燒學研討會, 2012.
43.陶文銓, “數值熱傳學, 西安交通大學出版社, 2004.
44.Sazhin, S.S., “Advanced models of fuel droplet heating and evaporation, Progress in Energy and Combustion Science, Vol. 32, p. 162-214, 2006.