W2為含觸媒之煤油基燃料，能與高濃度過氧化氫搭配作為自燃性雙基推進劑。具有高推進效能(Isp〜300sec)、無毒及高自主性之特性。為W2/過氧化氫推進劑組合所發展之液旋式噴注器具有機構簡單、易加工的優點，但其點火延遲不穩定、火焰之集中度仍有待改善。因此本研究設計液滴接觸實驗針對液旋式噴注器之點火機制進行探討，期望能透過研究結果對噴注器之點火延遲進行改良。
本研究應用液滴接觸實驗以高速攝影機(影格率10,000fps)觀察單滴W2(0.0146g)由不同高度(20cm/2.67gcm/s-60cm/4.65gcm/s)滴落衝擊25g厚度約7mm之過氧化氫(〜95.0wt%)液膜之點火過程。實驗觀察顯示，W2液滴與過氧化氫液膜接觸至點火可分為衝擊噴濺、液態觸媒反應及氣態點火反應三階段，而W2液滴動量(或衝擊高度)影響液滴接觸產生之撞擊坑面積，直接影響液態觸媒反應釋熱率與氣態點火反應的產生，為控制點火延遲時間的主要因素，但當撞擊坑面積過大時，W2局部濃度過低，會使得局部觸媒反應釋熱率減少，點火延遲因而增長。
本研究亦應用液滴接觸實驗之結果進行液旋式噴注器設計改進，改變W2噴霧角(40°-89°)，提昇W2噴霧衝擊過氧化氫液膜之正向動量，實驗結果顯示，點火延遲由3052.44 ms縮短至582.10 ms，驗證了推進劑接觸面積增加，增加單位時間熱生成，使點火延遲縮短之設計理念。

W2 is a kind of kerosene-base fuel with catalyst, and it can react with hydrogen peroxide as a hypergolic propellant combination. An injector which is called liquid cyclonic injector is developed for this propellant combination. However, the ignition delay of this injector is unstable. In this research, the droplet test is designed to study the ignition mechanism of the injector to improve the ignition delay of this injector.
The drop test observation shows the droplet of W2 from impacting the hydrogen peroxide liquid film to ignition can be divided to three steps: impact splash, liquid catalytic reaction, and gaseous ignition reaction. The area of the impact crater, which is affected by the momentum of the W2 droplet, affects the heat release rate from liquid catalytic reaction and leading the gaseous ignition reaction. It is the main factor controlling the ignition delay time. When the area is too large, the local concentration of W2 is too low to reduce the heat release rate of the local catalyst reaction and increase the ignition delay.
The result of the droplet contact experiment is used to improve the design of the liquid cyclonic injector. The spray angle of the W2 increases to increase the normal momentum of W2 spray impacting hydrogen peroxide liquid film. The result shows the ignition delay is shorten from 3052.44 ms to 582.10 ms. The design concept is verified by the result.

1.G.P. Sutton, and O. Biblarz, “Rocket Propulsion Element”, Seven Edition, John Wiley and Sons, Inc, U.S.A, p.4, p.6~8, p.250, p.254, p.257~259, 2001
2.M.J.L. Turner, “Rocket and Spacecraft Propulsion”, Third Edition, Praxis Publishing Ltd, Chichester, UK, p.73, p.102~103, 2009
3.B.M. Melof and M.C. Grubelich, “Investigation of Hypergolic Fuels with Hydrogen Peroxide”, 37th AIAA / ASME / SAE / ASEE Joint Propulsion Conference and Exhibit 8-11 July 2001
4.J. Rusek, K. Palmer, D. Bower, “United States Patent Application Publication Pub. No.: US 2005/0022911A1”, 2005
5.J.E. Funk, S.D. Heister, R. Humble and N. Purcell, “Development Testing of Non-Toxic, Storable Hypergolic Liquid Propellant”, 35th Joint Propulsion Conference and Exhibit 20, Los Angeles, CA, U.S.A., June 1999 - 24 June 1999
6.T.L. Pourpoint and W.E. Anderson, “Hypergolic Reaction Mechanisms Of Catalytically Promoted Fuels With Rocket Grade Hydrogen Peroxide”, Combustion Science and Technology, 2007
7.A.M. Kanury., “Introduction to Combustion Phenomena, Gordon and Breach”, Gordon and Breach Science Publishers, Inc., p.90, 1977
8.T.L. Pourpoint, “Hypergolic Ignition of A Catalytically Promoted Fuel With Rocket Grade Hydrogen Peroxide”, Doctor of Philosophy, Purdue University West Lafayette, December 2005
9.I.-H. She, T. Yuan, and Y.-T. Chen, “Auto-ignition of Kerosene/Hydrogen Peroxide Bipropellant”, AASRC Conference, Yunlin ,2015
10.P.-C. Shih and T. Yuan, “Enhancement of Liquid Mixing Between Propellants in Liquid Cyclonic Injector”, AASRC Conference, 2019
11.J. Xue, M. A. Jog, S. M. Jeng, E. Steinthorsson and M. A. Benjamin “Effect of Geometric Parameters on Simplex Atomizer Performance” , AIAA Journal, Vol. 42, No. 12, p.2408~2415, December 2004
12.Z. Kang, Z.-G. Wang, Q. Li and P. Cheng, “Effects of Trumpet on the Flow Characteristics of Pressure Swirl Injectors”, Journal of Propulsion and Power, Vol. 34, No. 4, p.947~959, July–August 2018
13.A. M. Worthington, “A Study of Splashes”, Longmans, Green, and Co., 39 Paternoster Row, London, New York, Bombay, and Calcutta, p.16, p.18, p.35, p.36, p.38, p.41, p.72, 1908
14.R. Mikkelsen, M. Versluis, E. Koene, G.-W. Bruggert, D. van der Meer, K. van der Weele, and D. Lohse, “Granular Eruptions: Void Collapse and Jet Formation”, Physics of Fluids 14, S14 ,2002
15.T. Pourpoint, W.E. Anderson, “Physical and Chemical Processes Controlling Fuel Droplet Ignition”, AIAA, 40th, 2004