NTO/MMH 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，故推進劑衝擊混合後之燃燒溫度分布會直接影響推進器性能，而NTO/MMH雙基推進器於實際應用上皆以富油燃燒狀態來操作，但是隨著氧化劑對燃料質量流率比增加，兩股噴流會因為動量通量差異過大，使得混合效率下降並且降低其燃燒效率。
本實驗根據Rupe提出的Rupe number ( )，改變噴注器孔徑比(NTO孔徑為0.24~0.49 mm，MMH孔徑固定為0.3 mm)，並固定噴流總質量流率(8 g/s)；進行NTO/MMH模擬溶液之冷流實驗(O/F=1.0~2.0；衝擊角為60°)，並以PLIF技術觀察衝擊點下10 mm處截面噴流質量機率分布，並且使用非均勻度(Patternation_Index)與混合效率(Em)等參數，分析不同孔徑比之噴流霧化混合狀態，並進而計算其絕熱火燄溫度，平均特徵速度。
實驗觀察顯示，相對能量密度較高之噴流，若孔徑較小，則會有穿透集中的現象;而若其孔徑較大，則會出現集中且腰子型分布。而當能量密度相等時，兩股噴流因獲得相同的能量轉換，使得霧化面分布較勻稱，因此有較佳的混合效率。而根據實驗結果表示在不同的O/F ratio狀況下，較佳的混合效率與平均特徵速度，皆是在 =0.5附近。而NTO/MMH反應之絕熱火燄溫度分布，在 =0.5之操作條件時，其高溫區分布亦較均勻。本研究顯示，改變雙衝擊噴流之噴注孔徑比，並滿足Rupe number=0.5之操作條件時，能改善因孔徑相同而動量通量差異造成的混合效率下降，並獲得較好的燃燒效率。因此，Rupe number為雙噴流衝擊霧化混合分布之重要參數。

The spontaneous ignition of impinging propellant jets construct the fundamental of thrust production of MMH/NTO thruster, thus, the impinging mixing of the propellants as well as the temperature distribution in the combustor have direct effect on the thruster performance. In practical design, the thruster is operated at fuel (MMH)-rich conditions. As the increase of the mass flow ratio of NTO to MMH (O/F), the mixing of the propellants becomes difficult and resulting in low combustion efficiency and unacceptable temperature distribution. By applying PLIF technique, this thesis research focused on the experimental observations of the impinging mixing of NTO and MMH simulates at various O/Fs(1.0-2.0) and orifice diameters (0.24mm-0.49mm) with constant total mass flow rate of 8g/s. The impinging angle was fixed at +30/-30. At 10mm downstream of the impinging point, the 2-D probability density distribution of mass of NTO and MMH were constructed, and hence the mixture ratio distribution, the mixing efficiencies (Em), and the patternation index (P.I.) at various conditions were determined. For the purpose to characterize the propulsion performance, the temperature distributions and the average characteristic velocities for various impinging conditions were also deduced.
The experiments showed that the energy densities as well as their ratio of the jets had a vital effect on jet’s breakup and mixing. For impinging jets with different jet’s diameters, the best mixing occurred at unity energy density ratio (Rupe number NR=0.5) of the two jets at the O/Fs investigated. For non-unity energy density ratio conditions, the higher energy density jet presented more concentrated mass distribution. After impingement, kidney-like shape of the 2-D distribution of the higher energy density jet with larger diameter was shown. This research was concluded with that the best mixing, the most uniform temperature distribution, as well as the best characteristic velocity can be achieved by varying the orifice size of the impinging jets to keep unity energy density ratio.

1. Lefebvre, A. H., Fuel Effects on Gas Turbine Combustion -Ignition, Stability and Combustion Efficiency, ASME J. Eng. Gas Turbine Power, Vol. 107,pp. 24-37, 1985.
2. Reeves, C.M., and Lefebvre, A. H., Fuel Effect 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 Paper861541, 1986.
4. Tate, R. W., “Spray Patternation,” Industrial and Engineering Chemistry, Vol. 52, pp. 49A-53A, 1960.
5. Lefebvre, A. H., Atomization and Sprays, Hemisphere Publishing Corporation, pp. 11-45, 1989.
6. N. Dombrowski and P. C. Hooper, “A Study Of Sprays Formed by Two Impinging Jets”, Journal of Fluid Mechanics, Vol. 18,part 3, pp.291-305, 1962.
7. N. Dombrowski and P. G. Hooper, “The Effect of Ambient Density on Drop Formation in Sprays”, Chemical Engineering Science,Vol.17, pp.291-305, 1962.
8. Rupe, J. H., “The Liquid Phase Mixing of a Pair of Impinging Streams”, Jet Propulsion Lab. Progress Report.20-195, California Inst. of Technology, Pasadena, CA,6 Aug 1953.
9. Rupe,J.H.,“A Correlation Between the Dynamic Properties of A Pair of Impinging Streams and the Uniformity of Mixture-Ratio Distribution in the Resulting Spray”, Jet Propulsion Lab. Progress Report.20-209, California Inst. of Technology, Pasadena, CA,28 March 1956.
10. Shuichi Ueda,Yukio Kuroda,and Hiroshi Miyajima,“Bipropellant Performance of N2H4/MMH Mixed Fuel in a Regeneratively Cooled Engine”,Kakuda Research Center,National Aerospace Laboratory,Miyagi 981-15,Journal of Propulsion and Power Vol.10,No.5,Sept.-Oct.1994.
11. Nasser Ashgriz, William Brocklehurst, and Douglas Talley, ”Mixing Mechanisms in a pair of Impinging Jets”, Journal of Propulsion and Power, Vol.17, No.3 May-June 2001.
12. 葉威廷，“噴流孔徑對衝擊霧化混合分布之影響”，成功大學航太所碩士論文，九十五學年度。
13. Schindler,R.C. and Schoenmant,L.,Development of a Five-Pound Thrust Bipropellant Engine,J. Spacecraft,Vol.13.No.7,pp.435-442,1976.
14. 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.
15. 黃柏霖， “5-lbf NTO/MMH 火箭推進劑衝擊霧化模擬之PLIF實驗觀察”，成功大學航太所碩士論文，九十四學年度。
16. 陳威丞，“衝擊噴流霧化混合之分析”，成功大學航太所博士論文，九十六學年度。
17. Eckbreth, A. C., Laser Diagnostics for Combustion Temperature and Species, Gordon and Breach Publisher, 1996.
18. J.C.Russ,The Image Processing Handbook,CRC Press,1992.
19. 田智元，“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。