以NTO/MMH為推進劑之雙基推進器因推進劑本身具有自發性燃燒現象，以及具有較高之比衝值(Isp>285 sec)，故被大量應用於衛星姿態控制與軌道轉換。本研究以NTO/MMH雙基推進器之噴注機構為研究目標，使用物理性質與NTO/MMH接近之模擬液為工作流體，以PLIF技術觀察不同環境壓力下之衝擊霧化現象。
根據NTO/MMH雙基推進器之設計，噴注器核心之之NTO與MMH質量流率比值(O/F)約為1.8；本研究設計之噴注單元的衝擊角固定為60；NTO噴注孔口直徑為0.52mm、質量流率為4.64g/s；而MMH噴注孔口直徑為0.4mm、質量流率為2.56g/s。實驗以PLIF技術觀察衝擊點下方10mm處截面霧化液滴之二維質量機率分布，分析其混合比分布，並經計算得其霧化、混合效率、絕熱火焰分布急及平均特徵速度。實驗結果顯示，環境壓力提升將提高噴流之空氣動力不穩定性(Aerodynamic Instability)，使得原本較穩定之MMH模擬液噴流可較有效之霧化，並與NTO模擬液產生較佳之混合，計算所得之平均特徵速度也隨壓力提高而提升。
本實驗另外針對噴流質量流率改變對於衝擊霧化之影響進行實驗觀察。以前述推進器設計之推進劑質量流率為標準，在85%至110%標準質量流率之間，進行衝擊霧化混合實驗觀察。結果顯示，在常壓時，最佳混合出現於100%之設定流率；當環境壓力提高時，衝擊噴流之混合皆較常壓為高，而最佳之混合則出現於107%流率。而在火箭所設計之燃燒室壓力環境下(100psi200psi)，調整推進劑流率於所設定之93%至110%之間，對NTO/MMH模擬液衝擊混合及燃燒特性將不致有明顯影響。

NTO/MMH thruster has been commonly adopted in spacecraft’s attitude and altitude control because of its high specific impulse (>285sec) and relatively simple system design for the hypergolic characteristics of the propellants. This research utilized the simulants that matched the physical properties of NTO and MMH as the work fluids to perform single-pair doublet impinging spray observations to justify the pressure effects on jets’ break-up and mixing as well as the performance of an existing NTO/MMH injector design.
In the injector design of NTO/MMH thruster, the mass flow rate ratio (O/F) in the combustion core was control at about 1.8 to avoid excess temperature rise. In this research, the mass flow rate of NTO simulant was set to be 4.64g/s from a 0.52mm diameter orifice, and the mass flow rate of MMH stimulant was 2.56g/s from a 0.4mm diameter orifice. The impinging angle of the two orifices was kept at 60. Besides analyzing the photo images of the spray fans, this study observed the probability distributions of mass of the cross section of the spray fan at the 10mm downstream of impinging point with PLIF technique to analyze the mixture ratios distribution, the mixing efficiency, the adiabatic flame temperature distribution, and the average characteristic velocity . The experimental result showed that the aerodynamic instability of jets increased with environmental pressure. Especially on the relatively stable jet of MMH stimulant, the increase of environmental pressure effectively increased the efficiency of atomization of MMH stimulant, thus increased the mixing efficiency of the impinging spray as well as the calculated average characteristic velocity.
This research also observed the impingements of NTO/MMH simulants within 85% to 110% of the above mentioned designed mass flow rates. From the analysis of the average characteristic velocity, environmental pressure stronger affected the performance of the injector at atmospheric pressure, and the most adequate mixing occurred at 100% of the designed mass flow rates . As the environmental pressure was raised, better mixing was shown. Under the designed pressure of the rocket combustor (100psi200psi), the most adequate mixing occurred at about 107% of the designed mass flow rates . The result showed that metering the mass flow rates of propellants between 93% with 110% of designed flow rates would not significantly affect the performance of the designed injector.

參考文獻
1. 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，中華民國九十四年。
2. 陳威丞、袁曉峰，”衝擊噴流霧化混合之分析”，成功大學航太所博士論文，中華民國九十六年。
3. 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，中華民國九十五年。
4. 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.
5. Heidmann, M. F., Priem, R. J., and Humphrey, J. C., “A Study if the Sprays Formed by Two Impinging Jets”, NACA-TN-3835, March, 1957
6. 黃祖宏、賴維祥，”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，中華民國八十七年。
7. Rupe, J. H., “The Liquid Phase Mixing of a Impinging Streams,” Jet Propulsion Lab. Progress Report.20-195, California Inst. Of Technology, Pasadena, CA,6 Aug 1953.
8. 林瑋倫，”噴流孔徑對雙衝擊霧化之影響”，成功大學航太所碩士論文，中華民國九十七年。
9. Yuan, T. and Chen, C., “An Observation of the Spray Phenomena of Unlike-triplet Impinging Jets,” 13th Annual National Conference on Combustion, Taiwan, 2002.
10. Chen, W. C., “The Analysis on the Breakup and Mixing of the Impinging Jets,” Ph. D Thesis, Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan, R.O.C., 2007.
11. Yuan, T., Chen, C., and Huang, B., “The Comparison of the Hot-Fire and Cold-Flow Observations of NTO/MMH Impinging Combustion,” AIAA-2007-0781.
12. 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.
13. Strakey, P. A., and Talley, D. G., “ Spray Characteristics of Impinging Jet Injector at High Back-Pressure,” Eighth International Conference on Liquid on Liquid Atomization and Spray Systems, Pasadena, CA, USA, July 2000.
14. 楊順傑、賴維祥，”同質酒精衝擊式霧化特性之研究”，成功大學航太所碩士論文，中華民國九十四年。

15. 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.
16. Eckbreth, A.C., Laser Diagnostics for Combustion Temperature and Species, Gordon and Breach Publisher, 1996.
17. Lefebvre,A. H., Atomization and Sprays, Hemisphere Publishing Corporation, pp. 11-45, 1989.