二硝酰胺铵(Ammonium dinitramide, ADN)是一种水溶性很好的高能绿色无机盐，其毒性低，对环境污染小。将其作为氧化剂与甲醇(Methanol, CH3OH)溶于水可以配置成ADN基液体推进剂，被认为有潜力取代使用广泛的单组元液体推进剂无水肼，应用于卫星的姿控发动机之中。本文针对ADN基液体推进剂的燃烧特性及其应用开展了相关的研究，综合运用实验研究、理论建模、模拟仿真等手段，系统地研究了推进剂从液相变为气相的蒸发热解过程、详细的气相化学反应机理、推进剂燃烧的火焰结构以及其在真实姿控发动机推力室内部的燃烧过程等四个主要问题。首先，针对ADN基液体推进剂由液相变为气相的蒸发热解过程，使用热重分析仪和居里点裂解仪分别在均匀慢速升温和急速升温这两种条件下进行了实验研究，并使用傅里叶变换红外光谱分析仪测量产物气体的组分和浓度。实验结果表明，在推进剂由液相变为气相的过程中，甲醇和水发生蒸发过程，而ADN发生热解反应，甲醇的蒸发过程和ADN的热解过程并不同步。为进一步分析ADN基液体推进剂的气相燃烧过程，建立了包含50组分235步化学反应的ADN-CH3OH详细气相化学反应机理，机理中ADN与甲醇之间的相互作用是通过ADN热解产生的氮氧化物气体小分子对于甲醇及其生成的含碳自由基的氧化过程来实现的。同时结合已有的实验数据对化学机理进行了验证。进一步，比对真实姿控发动机推力室的结构和尺寸，搭建了使用ADN基液体推进剂的模型燃烧室实验平台。在此平台上，以去离子水为介质，详细研究了喷注器的喷注雾化效果和液体在催化床多孔介质内的渗透流动过程。针对推进剂在常压条件下的燃烧过程，研究了催化床内的火焰传播过程和下游燃烧室内的火焰形态，测量了燃烧室内沿火焰轴向的温度分布；比对详细气相化学反应机理模拟得到的一维预混燃烧火焰的计算结果，总结出ADN基液体推进剂燃烧的火焰结构。针对姿控发动机推力室内部的燃烧过程，开发了相应的数值模拟方法，以Fluent软件作为求解器，研究了使用ADN基液体推进剂的姿控发动机在稳态运行工况和脉冲运行工况下推力室内部的流动燃烧情况，并结合热试车实验结果对发动机运行过程中推力室内发生的物理化学过程进行了讨论与分析。

Ammonium dinitramide (ADN) is a water-soluble high-energy green inorganic salt with reduced toxicity and environmental impact. A promising way for developing the ADN-based liquid propellant is to dissolve the oxidant ADN in a methanol(CH3OH)/water mixture. This kind of liquid propellant is considered to have the potential to replace the widely used monopropellant hydrazine and has applications in small space thrusters that control and adjust the orbits and attitudes of satellites. In this thesis, we investigated the combustion characteristics and applications of the ADN-based liquid propellant. Four major issues, including the evaporation and pyrolysis of the propellant from the liquid to the gas phase, the detailed mechanism of the gas-phase chemical reactions, the flame structure of the propellant and its combustion process in a small thruster of the attitude control engine, were investigated systematically by experimental and numerical methods. The evaporation and pyrolysis processes of the ADN-based liquid propellant from the liquid to the gas phase were investigated by a thermo-gravimetric analyzer and a Curie point pyrolysis unit, under slow and rapid heating rates, respectively. And the gas-phase products were detected and measured by a Fourier transform infrared spectroscopy. The results showed that during the phase transition from the liquid to the gas, methanol and water evaporated from the propellant, while ADN decomposed. The evaporation process of methanol and the decomposition process of ADN were not synchronous. To analyze the combustion process of the ADN-based liquid propellant, a detailed gas-phase ADN-CH3OH chemical reaction mechanism was established, containing 50 components and 235 reactions. In this mechanism, the interaction between ADN and methanol is accomplished through the oxidation process of methanol and other carbonous compounds by the ADN decomposition products. This chemical mechanism was verified by comparing the numerical results with the existed experimental data. Furtherly, a model combustion experiment system for the ADN-based liquid propellant was built, refering to the structure and size of the real thruster. With the help of this experiment system, we used the deionized water as the medium to test the atomization effect of the injector and investigated the liquid flowing process in the catalytic bed (porous media). In the combustion experiment of the propellant at 1 atm, we investigated the flame propagation process in the catalytic bed and the flame structere in the downstream combustion chamber, measuring the flame axial temperature distribution. By comparing the experimental results with the premixed flame numerical results based on the detailed gas-phase chemical mechanism, the flame structure of the ADN-based liquid propellant was concluded. A numerical method was developed and accomplished on the commercial software Fluent to investigate the combustion process of ADN-based liquid propellant in the thruster of the attitude control engine. The operating parameters of the thruster in steady operations and pulse operations were calculated and compared with the hot fire test. Then based on their comparisons, the physical and chemical processes of the ADN-based liquid propellant in the thruster were discussed and analyzed.