近年來，由於傳統的MMH/NTO推進劑組合具有高毒性及高腐蝕性，國際間近年來致力發展如煤油與過氧化氫這類的無毒綠色推進劑組合。其中煤油與過氧化氫之推進劑組合雖然具有高熱值、便宜、低毒性的特點，然而此組合並不具有自燃特性。因此本研究室以煤油作為基底加入醋酸錳作為均勻相觸媒調配出W2。液旋式噴注機構具有構造簡單的特性，更能限制氣相反應空間，用以減少熱散失、聚集熱能，進而自燃點火。
本研究為了改善液旋式噴注機構的點火延遲時間及穩定性，透過在反應壁面增鍍表面觸媒的方式使過氧化氫能更快速分解。為了使異相觸媒(銀、氧化銀、白金、二氧化錳、三氧化二錳和四氧化三錳)穩定附著於反應壁面，本研究自行開發燒結的程序。
本研究為了測試過氧化氫與不同異相觸媒的活性，設計了兩種實驗；第一種為過氧化氫(95%)與不同異相觸媒的反應時間測試，可從此定義過氧化氫與異相觸媒的反應過程，並計算反應時間；第二種為過氧化氫(20%)與不同異相觸媒的長時間分解速率測量。從以上兩者的結果可知氧化銀的活性最好，二氧化錳為次之。
本研究將氧化銀和二氧化錳觸媒實際應用於反應壁面中，並進行熱流點火實驗，分析有異相觸媒噴注器之點火延遲時間和比較與無異相觸媒噴注器的點火延遲時間。從結果得知有異相觸媒噴注器的點火延遲時間會逐漸增快到0.3秒至0.4秒趨於穩定。並與無異相觸媒噴注器比較後，發現有異相觸媒噴注器可以使點火延遲時間逐漸增快並且可以更加穩定。

SUMMARY
The combination of hydrogen peroxide and W2, which uses kerosene as a substrate to add manganese acetate as a homogeneous phase catalyst, is a promising bipropellant because of its high propulsive performance, low cost, low toxicity and hypergolic characteristics. The liquid cyclonic injector has the characteristics of simple structure, and can more restrict the gas phase reaction space, thereby reducing heat dissipation, collecting heat energy, and then igniting itself.
In order to improve the ignition delay and stability of the liquid cyclonic injector, the hydrogen peroxide can be decomposed more rapidly by plating the surface catalyst on the reaction wall. Besides, to stably adhere the heterogeneous catalysts (silver, silver oxide, platinum, manganese dioxide, dimanganese trioxide and trimanganese tetraoxide) to the reaction wall, the study develops its own sintering procedure.
This study designs two experiments, including drop test and decomposition rate measurement, to test the activity of hydrogen peroxide and different heterogeneous catalysts. From the results of two experiments, it is known that the activity of silver oxide is the best, and manganese dioxide is the second.
In this study, silver oxide and manganese dioxide catalysts are actually applied to the reaction wall, and conduct a heat-fire experiment to analyze the ignition delay of the heterogeneous catalyst injector and compare the ignition delay with the non-phase-contact catalyst injector. It is known from the results that the ignition delay of the heterogeneous catalyst injector gradually reduces to 0.3 seconds to 0.4 seconds and tends to be stable. After comparison with the non-phase-contact catalyst injector, it was found that the heterogeneous catalyst injector can gradually reduce the ignition delay time and can be more stable.
INTRODUCTION
In 2015, I-Hsuan She used a kerosene as subtrate and used manganese acetate as a hydrogen peroxide catalyst to formulate fuel, namely W2, which had a density of 0.81 g/cm^3 and a calorific value of about 32.3 KJ/g. The ignition time of W2 and high concentration hydrogen peroxide was about 20 ms (24 degrees Celsius, O/F = 0.8). For reducing the ignition delay time of W2 and hydrogen peroxide propellant combination, an injection mechanism had been developed, which was named liquid cyclonic injector. The concept of the liquid cyclonic injector is that the fuel and the oxidant are injected into the small cylindrical chamber at a high flow rate for spiral movement, so that the propellants can be rapidly mixed and the contact time is increased to promote the reaction heat release. Ignition occurs when the gas-phase temperature reaches its auto-ignition point. Jyun-Ci Guo used W2/hydrogen peroxide as propellants and used a liquid cyclonic injector for ignition experiments, and further studied its geometry and operating conditions. It was found that if the liquid cyclonic injector was designed to have a cavity diameter of 10 mm and injection orifice of 0.3mm, a shorter and stable ignition delay time could be obtained under the operating conditions of O/F=4 and total mass flow rate of 6 g/s to 7 g/s. Also, Jyun-Ci Guo observed the combustion products attached on wall of injector could promote the decomposition of hydrogen peroxide and the heat release rate so that the shorter ignition delay and wider ignition range were observed.
EXPERIMENTAL METHODS
This research is divided into three parts, the first one is to sinter manganese oxide on the surface, named manganese oxide preparation. And the second is drop test and decomposition rate measurement, to understand the activity of hydrogen peroxide for different heterogeneous catalysts. Finally, the best activity of heterogeneous catalysts would be applied to the liquid cyclonic injector and used in the hot-fire experiment, which ignition delay and ignition stability are discussed.
RESULTS AND DISCCUSION
In the results of manganese oxide preparation, it is found that after detection of manganese dioxide (Fig. 21), 35.5% are Pyrolusite-MnO2, and 17.6% of Ramsdellite-MnO2. The difference between the two is in the crystal structure. Also, the test results show that the manganese trioxide (Fig. 22) and trimanganese tetraoxide (Fig.23) is 100% pure substance.
The heterogeneous catalyst, manganese dioxide, dimanganese trioxide, trimanganese tetraoxide, silver, silver oxide and platinum, are done the activity tests with hydrogen peroxide. And tests can be divided into two types. The first one is a drop test in which 95% of hydrogen peroxide droplets (average 0.027 g/drop) are dropped on heterogeneous catalysts. The reaction time for decomposition of hydrogen peroxide and the reaction process defined by decomposition are tested. The second type is the decomposition rate measurement by placing a stainless-steel plate with a heterogeneous catalyst into an Erlenmeyer flask containing 20% and 20 ml by volume of hydrogen peroxide. The pressure generated by the releasing in oxygen is measured. From this, different heterogeneous catalysts react with hydrogen peroxide under long-term changes can be observed.
From the results of the drop test (Fig. 30), the activity of hydrogen peroxide on different heterogeneous catalysts is AgO>MnO2>Mn2O3>Mn3O4>Ag>Pt . From the decomposition rate measurement results (Fig. 35), the activity of hydrogen peroxide on different heterogeneous catalysts is AgO>MnO2>Mn2O3>Mn3O4. Above two results are compatible. In this experiment, the active silver oxide and manganese dioxide in the heterogeneous catalyst are best, so they are selected for the liquid cyclonic injector to carry out the hot-fire experiment, and the ignition delay time was analyzed.
In the hot-fire experiment, when comparing the average values of the first ignition delay times of two heterogeneous catalysts (Table 22 and Table 23), it is observed that the manganese dioxide catalyst injector is slightly faster than the silver oxide catalyst. In the subsequent ignition experiment, it is presumed that a large amount of manganese oxide, transformed from manganese acetate in the high temperature, is attached to the surface catalyst, so that the ignition delay tends to be reduced continuously. This trend tends to be stable from about 0.3 seconds to 0.4 seconds. Compare the ignition delay of the heterogeneous catalyst injector and the injector without the heterogeneous catalyst (Table 24), regardless of whether the non-phase catalyst injector is clean or not, there is a significant jitter at the ignition delay, and there are half the number of ignition failures. It can be seen that the liquid cyclonic injector with the heterogeneous catalyst can gradually reduce the ignition delay and can be more stable.
CONCLUSION
After multiple ignitions of the heterogeneous catalyst injector, the surface of the heterogeneous catalyst is heavily attached by manganese oxide, which contributes to the reduction of the ignition delay, and tends to stabilize from 0.3 seconds to 0.4 seconds, but the experimental results show that the ignition delay cannot be effectively reduced, only 5%-9% can be shortened, but the stability of the ignition delay time would be increase.
 

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