低推力雙基推進器主要應用於衛星姿態控制與軌道轉換等，MMH/NTO雙基推進器係藉由燃料與氧化劑衝擊碰撞產生自發性燃燒，故推進劑衝擊霧化後之燃燒溫度分布會直接影響推進器性能。本研究針對低推力(～5lbf)NTO/MMH推進器，以物理性質與NTO/MMH相似之模擬溶液(Simulants)進行冷流場之衝擊霧化實驗(mtotal 8g/sec；O/F=1.0~2.4；衝擊角為60°；噴孔直徑0.3mm)，並以PLIF技術觀察衝擊點下10mm處截面之雷射激發螢光訊號，經適當分析得其二維機率分布、混合比分布、絕熱火焰溫度分布與燃燒效率。實驗觀察顯示噴流之相對動量通量比與物理性質差異造成不同的二維機率與混合比分布；相對動量通量較高者，其質量分布較為集中(O/F=1.0時，MMH較集中；O/F=1.4~2.4時，NTO較集中)。但當相對動量通量比高至1.7(O/F=1.6)時，動量通量較低之MMH(絕對動量通量降低使雷諾數變小)因流體動力不穩定性(Hydrodynamic instability)降低使得噴流亦較不易碎裂霧化。當O/F=1.18時(動量通量比約為0.93)，整體與個別噴流的霧化截面皆具最佳的對稱性與均勻度(似橢圓形分布)，但O/F=1.79時(動量通量比約為2.14)，雖然整體與個別NTO的霧化截面偏移且高度集中，但其絕熱火焰溫度分布有其最佳燃燒效率。本研究亦以黏滯係數約「溶液B」1.8倍之「溶液C」進行同質(溶液C)與異質(溶液B與C)衝擊霧化實驗(固定動量比為1)。實驗結果顯示衝擊噴流的完全發展霧化模式會因黏滯係數增加而延遲發生；而「異質」衝擊噴流觀察得知於較低總流量6g/s時，噴流B與噴流C有不對稱(似腰子形)的霧化機率分布，且噴流C較噴流B為集中。隨著噴流動量通量增加(噴流的流體動力不穩定性增加)，噴流B與C的機率分布愈趨接近且均勻。但由於噴流B與C間黏滯係數的差異，故黏滯係數較大之噴流C仍維持較集中的機率分布。實驗觀察顯示黏滯係數與絕對動量通量(皆控制流場雷諾數)皆影響流體於噴管內部的流場型態(層流或紊流)，而紊流之流體動力不穩定性程度較層流高，較易因衝擊而碎裂霧化。故黏滯係數與絕對動量通量對衝擊後之噴流模式、霧化液滴分布皆有重要影響。

Low-thrust bipropellant propulsion systems are mainly applied on the attitude and altitude controls of satellites. The hypergolic phenomenon of NTO/MMH impingement constructs the required combustion for thrust generation and the flame temperature distribution has significant effect on thruster’s performance. This research utilized simulants which matching the physical properties (density, surface tension and viscosity) of NTO/MMH to perform the cold-flow impinging experiments of a 5-lbf rocket. The O/F ratios of NTO and MMH were varied from 1.0 to 2.4 while the total mass flow rate (~8g/sec), impinging angle(60°) and injector orifice(0.3mm) were kept constants. PLIF technique was adopted to observe the 2-dimensional probability distributions of mass for either or both liquids. The distributions of local mixture ratios and adiabatic flame temperatures were deduced from mass distributions. The experimental results revealed that the ratio of momentum flux and differences of physical properties affected the mass and mixture ratio distributions. The liquid jet with a larger momentum flux was more concentrated. However, when the ratio of momentum flux reached 1.7(O/F=1.6), the break-up of MMH jet having a lower momentum flux was less dispersed for its lack of hydrodynamic instability at very low speed. Although the most uniform and symmetrical mass distribution of spray appeared at O/F=1.2 that corresponding to the ratio of momentum flux close to unity, the pseudo combustion efficiency estimated from the adiabatic flame temperature distribution was not the optimum. The optimum combustion efficiency occurred at O/F=1.8 (the ratio of momentum flux2.1), where the total and NTO mass distributions were not uniformly dispersed and shifted from the centerline. This thesis research also performed the study of the effect of viscosity on the breakup of impinging jets. Like- and unlike -doublet impingements of test solution B (= 0.8510-3Ns/m2) and solution C (= 1.5910-3Ns/m2) were performed with various total mass flow rates while keeping the ratio of momentum flux to unity. The observations of the like-doublet impingements showed that a higher jet velocity was required to reach the fully-developed spray pattern for the higher viscosity fluid. The results of the unlike-doublet impingements revealed that the mass distribution of spray C (higher viscosity fluid) was more concentrated (more difficult to be dispersed) than that of spray B at low total mass flow rates (6.0g/sec) and both sprays were concaved to the side of the low viscosity jet. The difference of the uniformity of mass distributions due to their viscosity difference between two fluids became vague as the increase of the flow rates, however still distinguishable at the highest rate of 12.0g/sec. The analysis of the observations indicated that either viscosity or momentum flux affects the flow pattern inside the tube, that is, either laminar or turbulent flows. And, turbulent flow is easier to be atomized due to its higher hydrodynamic instability than laminar flow. As a result, viscosity and momentum flux, which are directly related to jet’s Reynolds number, have crucial effects on the spray pattern of impinging jets.

1.Lefebvre, A. H., Fuel Effects on Gas Turbine Combustion－Ignition, Stability, and Combustion Efficiency, ASME J. Eng. Gas Turbines Power, Vol. 107, pp. 24-37, 1985.
2.Reeves, C. M., and Lefebvre, A. H., Fuel Effects on Aircraft Combustor Emissions, ASME Paper 86-GT-212, 1986.
3.Rink, K. K., and Lefebvre, A. H., Influence of Fuel Drop Size and Combustor Operating Conditions on Pollutant Emissions, SAE Technical Paper 861541, 1986.
4.Lefebvre, A. H., Atomization and Sprays, Hemisphere Publishing Corporation, pp. 11-45, 1989.
5.Bidone, G., Experience sur la Forme et sur la Direction des Veines et des Courants d’Eau Lances par Diverses Ouvertures, Imprimerie Royale, Turin, pp. 1-136, 1829.
6.Savart, F., Ann. Chim. Phys., Vol. 53, pp. 337-386, 1833.
7.Schweitzer, P. H., Mechanism of Disintegration of Liquid Jets, J. Appl. Phys., Vol. 8, pp. 513-521, 1937.
8.Sterling, A. M., The Instability of Capillary Jets, Ph. D. thesis, University of Washington, 1969.
9.McCarthy, M. J., and Molloy, N. A., Review of Stability of Liquid Jets and the Influence of Nozzle Design, Chem. Eng. J., Vol. 7, pp. 1-20,1974.
10.Sterling, A. M., and Sleicher, C. A., The Instability of Capillary Jets, J. Fluid Mech., Vol. 68, pp. 477-495,1975.
11.M.F. Heidmann and R.J.Priem, ”A Study of Sprays Formed by Two Impinging Jets”, NACA-TN-3835, March 1957
12.江滄柳、賴維祥、黃文榮，同質衝擊噴流特性之研究，成功大學航太所博士論文，八十六學年度。
13.D. Grapper, N. Dombrowski, W. P. Jepson and G. A. D. Pyott, ”A Note on the Growth of Kelvin-Helmholtz Waves on Thin Liquid Sheets”, Journal of Fluid Mechanics, Vol. 57, part 4, pp.671-672, 1973.
14.N. Dombrowski and P. G. Hopper, “The Effect of Ambient Density on Drop Formation in Sprays”, Chemical Engineering Science, Vol. 17, pp. 291-305, 1962.
15.N. Dombrowski and P. G. Hopper, “A Study if the Sprays Formed by Impinging Jets in Laminar and Turbulent Flow”, Journal of Fluid Mechanics, Vol. 18, part 3, pp.392-400, 1964.
16.N. Dombrowski and W. R. Johns, “The Aerodynamics Instability and Disintegration of Viscous Liquid Sheets”, Chemical Engineering Science, Vol. 18, pp. 203-214, 1963.
17.W.H. Nurick, ”Orifice Cavitation and Its Effects on Spray Mixing”, Journal of Fluid Engineering, pp. 681-687, December 1976.
18.M. C. Kline and R. D. Woodward, ” Imaging of Impinging Jet Breakup and Atomization Process Using Copper-Vapor-Laser-Sheet-Illuminated Photography”, Non-Intrusive Combustion Diagnostics, Kuo and Parr Eds., Begell House, INC., pp. 552-568, 1994.
19.賴維祥、黃祖宏，液體物理性質對衝擊式注油器霧化特性之研究，成功大學航太所碩士論文，八十六學年度。
20.陳威丞、袁曉峰，異質噴流衝擊霧化之觀察，成功大學航太所碩士論文，八十九學年度。
21.L. B. Zung, and J. R. White, ” Combustion Process of Impinging Hypergolic Propellants”, NASA-CR-1704.
22.B. R. Lawver,” Photographic Observation of Reactive Stream Impingement”, NASA-79-0154.
23.Kihoon Jung, Youngbin Yoon and San-Soon Hwang, ”Spray Characteristics of Impinging Jet Injectors Using Imaging Techniques”, 36th AIAA Joint Propulsion Conference, Jun AIAA, 2000.
24.Renaud Lecourt, Robert Foucaud, Gerard Lavergne, Pierre Berthoumieu and Pierre Millan, ”Hypergolic Propellant Burning Spray Visualization by Laser Sheet Method: Application to Droplet Size and Liquid Concentration Measurement”,Fed-Vol.172, Experimental and Numerical Flow Visualization, ASME 1993.
25.王修哲、賴維祥，同質與異質衝擊式注油器霧化特性研究，成功大學航太所碩士論文，九十學年度。
26.Yuan, T. and Chen, C., “Observations of the Spray Phenomena of Unlike-doublet Impinging Jets”, 11th International Symposium on Flow Visualization, 2004 (USA).
27.Sankar, S. V., Maher, K.E., Robart, D. M., Bachalo, W. D., Rapid Characterization of Fuel Atomizers Using an Optical Patternator, Journal of Engineering for Gas Turbine and Power, Vol. 121, pp. 409-414, 1999.
28.Eckbreth, A. C., Laser Diagnostics for Combustion Temperature and Species, Gordon and Breach Publisher, 1996.
29.Schindler, R. C. and Schoenmant, L., Development of a Five-Pound Thrust Bipropellant Engine, J. Spacecraft, Vol. 13. No. 7, pp. 435-442, 1976.
30.Stechman, R. C. and Smith, J. A., Monomethyl Hydrazine vs. Hydrazine Fuels: Test Results Using Flight Qualified 100 lbf and 5 lbf Bipropellant Engine Configurations, AIAA-83-1257, 1983.
31.Talley, D. G., J. F., Verdieck, Lee, S. W., Mcdonell, V. G. and Samuelsen, G. S., Accounting for Laser Sheet Extinction in Applying PLLIF to Sprays, AIAA-96-0469, 1996.
32.J. C. Russ, The Image Processing Handbook, CRC Press, 1992.
33.田智元、葉俊良，液態推進燃料噴注模擬實驗與分析，大葉大學機械所碩士論文，八十九學年度。
34.Robert W. Fox and Alan T. McDonald, Introduction to Fluid Mechanics, John Wiley & Sons, Inc., pp. 360, 1998.
35.P.R.K. Chetty, Satellite Technology and Its Applications, TAB BOOKS Inc., pp. 230-244, 1988.
36.鍾易全、袁曉峰，衝擊噴流之混合現象觀察，成功大學航太所碩士論文，九十二學年度。