臺灣博碩士論文加值系統

　　本研究目的在以實驗研究、數值方法和理論分析三大部分來探討沖擊噴流流場中火焰特性，以了解一負拉伸火焰(曲面火焰)在正拉伸流場(停滯面流場)中的燃燒特性。
　　由實驗研究的結果發現，建立於沖擊噴流流場中的錐形火焰會存在一火焰多重性濃度區間(double-solution zone)，經由甲烷濃度調整方式的不同(由富油降至貧油或者由貧油增加至富油)，火焰面於同樣的流場設定下，會有兩種存在的位置以及形態。於此濃度區間內，火焰若受到外在機械性干擾，則火焰形態可在平面火焰與錐形火焰間變換，即火焰於此區間內為不穩定狀態。火焰多重性濃度區間會明顯受到流速以及停滯面板到噴嘴出口距離的影響，與停滯面種類則較無關聯性。在較低流速或較低停滯面與噴嘴出口距離下，火焰多重性濃度區間會減小。火焰重複區間的不穩定性會影響到火焰形態，因此在設計沖擊噴流燃燒器上須予以考慮，特別是貧油燃燒的狀況。
　　火焰面拉伸率估算結果顯示，沖擊噴流流場中的甲烷錐形火焰其整體火焰面承受負拉伸作用，但停滯面流的流場正拉伸作用會使得負拉伸效應減弱；當火焰呈現開口狀或者是平面火焰形態時，火焰面才會承受正拉伸作用。
　　理論分析與實驗研究所得到的結果相互吻合，對於一沖擊噴流中的富油甲烷錐形火焰(Le>1)而言，流場正拉伸與下游停滯面熱損失均為負效應，會使得火焰燃燒強度減弱；而對於沖擊噴流中的貧油甲烷錐形火焰(Le<1)而言，下游熱損失仍為負效應，但是流場正拉伸則是正效應。

　　This investigation is aimed at studying the characteristics of laminar conical premixed flames in an impinging jet flow experimentally, numerically, and theoretically with emphasis on the effects of negative flame stretch from flame curvature, positive stretch from the flow field and preferential diffusion.
　　The results show that flame shapes exhibit double-solution characteristics in a certain range of methane concentration. Experimentally, by following different paths of adjusting methane concentration (decreasing from rich to lean or increasing from lean to rich), two different flame configurations (planar or conical flame) may exist at the same flow conditions: burner-to-plate distance, inlet velocity and methane concentration. At the higher (or lower) critical methane concentration, the transition from a flat flame to a conical flame (or from a conical flame to a flat flame) occurs. When the operating condition is in this region, the flame is unstable since an externally mechanical disturbance may transform the flame shape back and forth between conical flame and flat flame, i.e., flames in the double solution region are unstable. The double solution region is strongly influenced by the burner-to-plate separation distance (H/d) and inlet velocity. Lower H/d or lower inlet velocity decreases the double solution region; In other words, the flame is relatively stable at lower H/d or lower inlet velocity. Instability in the double solution region may strongly affect the flame shapes. Therefore, the design of low-Reynolds-number heating devices, such as domestic gas burners, should take the double solution region into consideration, especially for those used in lean premixed flame applications.
　　Stretch calculation along a conical flame in an impinging flow shows the conical flame still endures negative stretch. However, the effect of positive flow stretch due to the impinging flow reduces the extent of negative stretch. When the methane flame is outward open-tip or flat, it then receives positive stretch.
　　Theoretical analysis reveals that for a negatively-stretched conical flame in a positively-stretched flow, positive stretch is a positive effect to the lean methane flame (Le<1), but negative to rich methane flame (Le>1). The downstream heat loss is a negative effect to both rich and lean methane flame (Le>1 and Le<1). Experimental results agree well with the theoretical and numerical analysis qualitatively.

總目錄 I
表目錄 IV
圖目錄 V
符號說明 VIII
一、前言 1
1-1 沖擊噴流流場 2
1-2 沖擊噴流火焰 5
1-3 研究目的 14
二、實驗設備與方法 17
2-1 沖擊噴流燃燒器系統 17
2-2 高溫熱電偶溫度量測系統 18
2-3 影像處理系統 19
2-4 實驗參數及研究方法 19
三、冷流場數值分析 23
3-1 基本假設 23
3-2 統御方程式 24
3-3 邊界條件 26
四、火焰面理論預測 30
五、火焰面拉伸率估算 36
六、正拉伸流場中負拉伸火焰理論分析 39
6-1 幾何描述與基本假設 40
6-2 統御方程式 41
6-3 擴散區展開 45
6-4 反應區展開 46
6-5 最後解 47
6-6 參考數值與預測模式 50
七、結果討論 53
7-1 火焰型態 54
7-2 火焰轉變過程 63
7-3 冷流場數值分析 66
7-4 火焰面預測 69
7-5 火焰面拉伸率估算 71
7-6 火焰面溫度變化 74
7-7 正拉伸流場中負拉伸火焰分析 77
八、結論 81
九、參考文獻 84
十、圖表 93

1.Narayanan, V., Seyed-Yagoobi, J., and Page, R.H., "An Experimental Study of Fluid Mechanics and Heat Transfer in an Impinging Slot Jet Flow," Int. J. Heat Mass Transfer, Vol. 47, pp. 1827-1845, 2004.
2.Sforza, P.M., Steiger, M.H., and Trentacoste, N., "Studies on Three-dimensional Viscous Jets," AIAA J. Vol. 4, pp. 800-806, 1966.
3.Trentacoste, N., and Sforza, P.M., "Further Experimental Results for Three-dimensional Viscous Jets ," AIAA J. Vol. 5, pp. 885-891, 1967.
4.Narayanan, V., Seyed-Yagoobi, J., and Page, R.H., "An Experimental Study of Fluid Mechianics and Heat Transfer in an Impinging Slot Jet Flow," Int. J. Heat Mass Transfer, Vol. 47, pp. 1827-1845, 2004.
5.Livinggood, J.N.B., and Hrycak, P. "Impingement Heat Transfer from Turbulent Air Stream Jets to Flat Plates," NASA TM X-2778, 1973.
6.Sung, C.J., Liu, J.B., and Law, C.K., "On the Scalar Structure of Nonequial Diffusive Premixed Flames in Counterflow," Combust. Flame, Vol. 106, pp. 168-183, 1996.
7.Seshadri, K., "The Asymptotic Structure of a Counterflow Premixed Flame for Large Activation Energies," Int. J. Eng. Sci., Vol. 21, pp. 103-111, 1983.
8.Darabiha, N., Candel, M., and Marble, E., "The Effect of Strain Rate on a Premixed Laminar Flame," Combust. Flame, Vol. 64, pp. 203-217, 1986.
9.Lin, T.H., and Sohrab, S.H., "On the Transition of Diffusion to Premixed Flames Flames in Conserved Systems," Combust. Flame, Vol. 68, pp. 73-79, 1987.
10.Hou, S.S., Yang, S.S., and Lin, T.H., "An experimental study on combustion characteristics of flames in a coaxial flow with a stagnation point," Int. J. Heat Mass Transfer, Vol. 47, pp. 947-958, 2004.
11.Schlichting, H., Boundary Layer Theory, Seventh Ed., McGraw-Hill, New York, pp. 94-111, 1979.
12.Karimipanah, T., and Awbi., H.B., "Theoretical and Experimental Investigation of Impinging Jet Ventilation and Comparison with Wall Displacement Ventilation," Building and Environment, Vol. 37, pp. 1329-1342, 2002.
13.Donaldson, C.D., and Snedeker, R.S., "A Study of Free Jet Impingement. Part 1. Mean Properties of Free and Impinging Jets," J. Fluid Mech., Vol. 45, pp. 281-319, 1971.
14.Donaldson, C.D., Snedeker, R.S., and Margolis, D.P., "A Study of Free Jet Impingement. Part 2. Free Jet Turbulent Structure and Impingement Heat Transfer," J. Fluid Mech., Vol. 45, pp. 477-512, 1971.
15.Lytle, D., and Webb, B.W., "Air Jet Impingement Heat Transfer at Low Nozzle-plate Spacing," Int. J. Heat Mass Transfer, Vol. 37, pp. 1687-1697, 1994.
16.Tong, A.Y., "A Numerical Study on the Hydrodynamics and Heat Transfer of a Circular Liquid Jet Impinging onto a Substrate," Numerical Heat Transfer, Vol. 44, pp. 1-19, 2003.
17.Dong, L.L., Cheung, C.S., and Leung, C.W., "Heat Transfer From an Impinging Premixed Butane/Air Slot Flame Jet," Int. J. Heat Mass Transfer, Vol. 45, pp. 979-992, 2002.
18.Dong, L.L., Leung, C.W., and Cheung, C.S., "Heat Transfer of a Row of Three Butane/Air Flame Jets Impinging on a Flat Plate," Int. J. Heat Mass Transfer, Vol. 46, pp. 113-125, 2003.
19.Byrne, J.F., "The Influence of Atmospheric Oxygen on Bunsen Flames," Fourth Symposium (International) on Combustion, The Combustion Institute, pp. 345-348. 1952.
20.Kimura, I., and Ukawa, H., "Studies on the Bunsen Flames of Fuel-Rich Mixtures," Eighth Symposium (International) on Combustion, The Combustion Institute, pp. 521-523, 1960.
21.Lewis, B., and von Elbe, G., Combustion Flames and Explosion of Gases, Third Edition, Academic Press, New York, pp. 274-301, 1987.
22.Wagner, T.C., and Ferguson, C.R., "Bunsen Flame Hydrodynamics," Combust. Flame, Vol. 59, pp. 267-272, 1985.
23.Sung, C.J, Yu, K.M., and Law, C.K., "On the Geometry and Burning Intensity of Bunsen Flames," Combust. Sci. and Tech., Vol. 100, pp. 245-270, 1994.
24.Law, C.K, Ishizuka, S., and Cho, P., "On the Opening of Premixed Bunsen Flame Tips," Combust. Sci. and Tech., Vol. 28, pp. 89-96, 1982.
25.Mizomoto, M., Asaka, Y., Ikai, S., and Law, C.K, "Effects of Preferential Diffusion on the Burning Intensity of Curved Flames," Twentieth Symposium (International) on Combustion, The Combustion Institute, pp. 1933-1939, 1984.
26.Mizomoto, M., and Yoshida, H., "Effects of Lewis Number on the Burning Intensity of Bunsen Flames," Combust. Flame, Vol. 70, pp. 47-60, 1987.
27.Law, C.K, Cho, P., Yoshida, H., and Mizomoto, M., "Flame curvature and Preferential Diffusion in the Burning Intensity of Bunsen Flames," Twenty-first Symposium (International) on Combustion, The Combustion Institute, pp. 1803-1809, 1986.
28.Echekki, T. and Mungal, M.G., "Flame Speed Measurements at the Tip of a Slot Burner: Effects of Flame Curvature and Hydrodynamic Stretch," Twenty-Third Symposium (International) on Combustion, The Combustion Institute, pp. 455-461, 1990.
29.Bradley, D., Gaskell, P.H., Kwan K.C., and Scott, M.J, "Two- dimensional Mathematical Modeling of Laminar, Premixed, Methane-air Combustion on an Experimental Slot Burner," Twenty-Sixth Symposium (International) on Combustion, The Combustion Institute, pp. 915-921, 1996.
30.Kim, Y.D., and Matalon, M., "Propagation and Extinction of a Flame in a Stagnation-Point Flow," Combust. Flame, Vol. 73, Issue 3, pp. 303-313, 1988.
31.Ishizuka, I., and Law, C.K., "An Experimental Study on Extinction and Stability of Stretched Premixed Flames," Nineteenth Symposium (International) on Combustion, The Combustion Institute, pp. 327-335, 1982.
32.Sato, J., "Effects of Lewis Number on Extinction Behavior of Premixed Flames in a Stagnation Flow," Nineteenth Symposium (International) on Combustion, The Combustion Institute, pp. 1541-1548, 1982.
33.Tsuji, H., and Yamaoka, I., "Structure and Extinction of Near-limit Flames in a Stagnation Flow," Nineteenth Symposium (International) on Combustion, The Combustion Institute, pp. 1533-1540, 1982.
34.Chao, B.H., and Law, C.K., "Asymptotic Theory of Flame Extinction with Surface Radiation," Combust. Flame, Vol. 92, pp. 1-24, 1993.
35.Sato, J., and Tsuji, H., "Extinction of Premixed Flames in a Stagnation Flow Considering General Lewis Number," Combust. Sci. Tech., Vol. 33, pp. 193-205, 1983.
36.Yamaoka, I., Tsuji, H, and Harigaya, Y, "Extinction and Structure of Methane/Very Lean Methane-Air Counterflow Diffusion Flames," Twenty-first Symposium (International) on Combustion, The Combustion Institute, pp. 1837-1842, 1986.
37.Sohrab, S.H., Ye, Z.Y., and Law, C.K., "An Experimental Investigation on Flame Interaction and the Existence of Negative Flame Speeds," Twentieth Symposium (International) on Combustion, The Combustion Institute, pp. 1957-1965, 1984.
38.Yamamoto, K., and Ishizuka, S., "Temperatures of Positively and Negatively Stretched Flames," JSME Int. J. Series B, Vol. 46, No. 1, pp. 198-204, 2003.
39.Yokomori, T., and Mizomoto, M., "Flame Temperatures along a Laminar Premixed Flame with a Non-uniform Stretch Rate," Combust. Flame, Vol. 135, pp. 489-502, 2003.
40.Sinibaldi, J.O., Driscoll, J.F., Mueller, C.J., Donbar, J.M., Carter, C.D., "Propagation Speeds and Stretch Rates Measured along Wrinkled Flames to Access the Theory of Flame Stretch," Combust. Flame, Vol. 133, pp. 323-334, 2003.
41.Kitano, M., and Otsuka, Y., "On Flammability Limits and Flame Shapes of Counter Flow Premixed Flames," Combust. Sci. and Tech., Vol. 48, pp. 257-271, 1986.
42.Ishizuka, S., and Law, C.K., "An Experimental Study on Extinction and Stability of Stretched Premixed Flames," Nineteenth Symposium (International) on Combustion, The Combustion Institute, pp. 327-335, 1982.
43.Hou, S.S., Yang, S.S., Chen S.J., and Lin, T.H, "Interactions for Flames in a Coaxial Flow with a Stagnation Point," Combust. Flame, Vol. 132, pp. 58-72, 2003.
44.Egolfopoulos, F.N., Zhang, H., and Zhang, Z., "Wall Effects on the Propagation and Extinction of Steady, Strained, Laminar Premixed Flames," Combust. Flame, Vol. 109, pp. 237-252, 1997.
45.Vagelopoulos, C.M, and Egolfopoulos, F.N., "Direct Experimental Determination of Laminar Flame Speeds," Twenty-Seventh Symposium (International) on Combustion, The Combustion Institute, pp. 513-519, 1998.
46.Hou, S.S., Ko, Y.C., "Effects of Heating Height on Flame Appearance, Temperature Field and Efficiency of an Impinging Jet Flame," Energy Conversion, Vol. 45, pp. 1583-1595, 2004.
47.Zhang, Y., and Bray, K.N.C., "Characterization of Impinging Jet Flames," Combust. Flame, Vol. 116, pp. 671-674, 1999.
48.Zhang, Y., Rogg, B., and Bray, K.N.C., "Temporally and Spatially Resolved Investigation of Flame Propagation and Extinction in the Vicinity of Walls," Combust. Sci. Tech., Vol. 113, pp. 255-271 (1996).)
49.Foat, T., Yap, K.P., and Zhang, Y., "The Visualization and Mapping of Turbulent Premixed Impinging Flames," Combust. Flame, Vol. 125, pp.839-851, 2001.
50.Schuller, T., Durox, D, and Candel, S., "Dynamics of and Noise Radiated by a Perturbed Impinging Premixed Jet Flame," Combust. Flame, Vol. 128, pp. 88-110, 2002.
51.林建昌，"停滯面噴霧燃燒器之設計實作及柴油燃燒分析，" 國立成功大學機械工程研究所碩士論文，民國84年6月。
52.Patankar, S.V., Numerical Heat Transfer and Fluid Flow, Hemisphere, New York, 1980.
53.汪慶雲，"紊流效應對燃燒現象影響之研究，" 國立成功大學航空太空工程研究所碩士論文，民國77年6月。
54.Sheu, W.J., and Sivashinsky, G.I., "Nonplanar Flame Configurations in Stagnation Point Flow," Combust. Flame, Vol. 84, pp. 221-224, 1991.
55.Zhu, D.L., Egolfopoulos, F.N., and Law, C.K., "Experimental and Numerical Determination of Laminar Flame Speeds of Methane/(Ar, N2, CO2)-Air Mixtures as Function of Stoichiometry, Pressure, and Flame Temperature," Twenty-Second Symposium (International) on Combustion, The Combustion Institute, pp. 1537-1545, 1988.
56.Karlovitz,B., Denniston, D. W., Jr., Knappascharefer, D.H., and Wells, F.E., "Studies in Turbulent Flames," Fourth Symposium (International) on Combustion, The Combustion Institute, pp. 613-620, 1953.
57.Markstein, G.H., Nonsteady Flame Propagation, Pergamon Press, Oxford, 1964.
58.Williams, F.A., Combustion Theory, Menjamin-Cummins, Palo Alto, CA, 1985.
59.Buckmaster, J.D., "The Quenching of Two-Dimensional Premixed Flames," Acta Astronautica, Vol. 6, pp. 741-769, 1979.
60.Chung, S.H., and Law, C.K., "An Invariant Derivation of Flame Stretch," Combust. Flame, Vol. 55, pp. 123-125, 1984.
61.Bradley, D., Lau, A.K.C., and Lawes, M., "Flame Stretch Rate as a Determinant of Turbulent Burning Velocity," Trans. R. Soc. Lond. A338, pp. 359-3887, 1992.
62.Matalon, M. "On Flame Stretch," Combust. Sci. and Tech., Vol. 31, pp. 169-181, 1983.
63.Takeno, T., Nishioka, M., and Ishizuka, S., "A Theoretical Study of Extinction of a Tubular Flame," Combust. Flame, Vol. 66, pp. 271-283, 1986.
64.Ju, Y., Masuya, G., Liu, F., Hattori, Y., and Riechelmann, D., "Asymptotic Analysis of Radiation Extinction of Stretched Premixed Flames," Int. J. Heat Mass Transfer, Vol. 43, pp. 231-239, 2000.
65.Hou, S.S., "The Interaction between Internal Heat Loss and External Heat Loss on the Extinction of Stretched Spray Flames with Nonunity Lewis Number," Int. J. Heat Mass Transfer, Vol. 46, pp. 311-322, 2002.
66.Sohrab, S.H., and Law, C.K., "Extinction of Premixed Flames by Stretch and Radiative Loss," Int. J. Heat Mass Transfer, Vol. 27, pp. 291-300, 1984.
67.Liu, F., Smallwood, G.J., Gulder, O.L., and Ju, Y., "Asymptotic Analysis of Radiative Extinction in Counterflow Diffusion Flames of Nonunity Lewis Number," Combust. Flame, Vol. 121, pp. 275-287, 2000.
68.Seiser, R., Seshadri, K., Piskernik, E., and Linan, A., "Ignition in the Viscous Layer between Counterflowing Streams: Asymptotic Theory with Comparison to Experiments," Combust. Flame, Vol. 122, pp. 339-349, 2000.
69.Sivashinsky, G.I., "The Diffusion Stratification Effect in Bunsen Flames," J. Heat Transfer, Vol. 96, pp. 530-535, 1974.
70.Sivashinsky, G.I., "Structure of Bunsen Flames," J. Chem. Phy., Vol. 62, No. 2, pp. 638-643, 1975.
71.Buckmaster, J., "A Mathematical Description of Open and Closed Flame Tips," Combust. Sci. Tech., Vol. 20, pp. 33-40, 1979.
72.Liu, C.C., and Lin, T.H., "The Interaction between External and Internal Heat Losses on the Flame Extinction of Dilute Sprays," Combust. Flame, V.85, p.468-478, 1991.
73.Reid, R.C., Prausnitz, J.M., and Sherwood, T.K., The Properties of Gases and Liquids, Third Edition, McGraw Hill, New York, 1977.