2-Azido-N,N-Dimethylethanamine (DMAZ) and tetramethylethylenediamine (TMEDA) are promising green propellants for hypergolic applications, and blending DMAZ with TMEDA can achieve short ignition delay time (IDT) and comparable specific impulse to hydrazine-based fuels simultaneously. There are reports of a synergistic effect between DMAZ and TMEDA, but its mechanism is not well understood. In this work, drop tests and gas-phase autoignition experiments were combined to provide insights of this synergistic effect from different aspects. The drop tests of DMAZ/TMEDA blends with white-fuming nitric acid were conducted in a confined transparent chamber with controlled O2 concentration. Results show that the hypergolic ignition is much faster for blends with 20–40 wt% DMAZ under all O2 concentration conditions, and higher concentration of O2 in the environment significantly promotes the hypergolic ignition process. To further investigate the chemistry between DMAZ/TMEDA with O2, gas-phase IDTs were measured using a rapid compression machine and a shock tube in a wide temperature range of 500–1100 K and at pressure of 10 bar. TMEDA shows a higher reactivity at lower temperatures (<690 K), while the autoignition of DMAZ is much faster at higher temperatures (>690 K). A synergistic effect between DMAZ and TMEDA was also observed in the gas-phase autoignition, i.e., fuel blend with 30 % DMAZ showed equal or even lower IDTs than pure TMEDA at lower temperatures. The newly measured IDTs of DMAZ/TMEDA were further adopted to validate a previously developed chemical kinetic model for pure TMEDA and DMAZ, which exhibits good predictions for the blending effects nonetheless. Kinetic analyses reveal that the low-temperature reactivity contributed from the TMEDA can be enhanced by the heat release from DMAZ decomposition, causing the synergistic effect in gas-phase autoignition of DMAZ/TMEDA blends.

中文翻译：

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了解绿色推进剂 2-叠氮基-N,N-二甲基乙胺和四甲基乙二胺的协同效应：从跌落测试到气相自燃


2-叠氮基-N,N-二甲基乙胺 (DMAZ) 和四甲基乙二胺 (TMEDA) 是用于自燃应用的有前途的绿色推进剂，将 DMAZ 与 TMEDA 混合可以同时实现短点火延迟时间 (IDT) 和与肼基燃料相当的比冲。有报道称 DMAZ 和 TMEDA 之间具有协同作用，但其机制尚不清楚。在这项工作中，跌落测试和气相自燃实验相结合，从不同方面提供了这种协同效应的见解。 DMAZ/TMEDA 混合物与白烟硝酸的跌落测试是在 O2 浓度受控的密闭透明室中进行的。结果表明，在所有 O2 浓度条件下，含有 20-40 wt% DMAZ 的混合物的自燃点火速度要快得多，并且环境中较高浓度的 O2 显着促进了自燃点火过程。为了进一步研究 DMAZ/TMEDA 与 O2 之间的化学反应，使用快速压缩机和激波管在 500–1100 K 的宽温度范围和 10 bar 的压力下测量气相 IDT。 TMEDA 在较低温度 (<690 K) 下表现出较高的反应活性，而 DMAZ 在较高温度 (>690 K) 下自燃速度要快得多。在气相自燃中还观察到 DMAZ 和 TMEDA 之间的协同效应，即在较低温度下，含有 30% DMAZ 的燃料混合物显示出与纯 TMEDA 相同甚至更低的 IDT。进一步采用新测量的 DMAZ/TMEDA 的 IDT 来验证先前开发的纯 TMEDA 和 DMAZ 的化学动力学模型，该模型仍然对混合效果表现出良好的预测。 动力学分析表明，TMEDA 的低温反应性可以通过 DMAZ 分解释放的热量得到增强，从而导致 DMAZ/TMEDA 共混物气相自燃的协同效应。