Abstract The hypergolic interaction and ignition delay times of catalytically promoted solidified ethanol (CPSE) formulated using organic gellant, namely, methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC), has been investigated using rocket grade hydrogen peroxide (90% RGHP; H2O2) as an oxidizer, for the use in hybrid rocket engines. Using iso-conversional Friedman method, the apparent activation energy (Ea) is found to be in the range of 9.06–14.01 kJ/mol for unloaded solidified ethanol samples. The hypergolic ignition delay (ID) of the CPSE fuels with H2O2 are investigated using manganese (III) acetylacetonate (Mnacac) as a catalyst using the drop-test method and found that the ID lies in the range of 49–307 ms. Five-stage events are identified based on the signals from the high-speed camera, photodiode, and microphone obtained from the drop-test. Stage I: prior to of H2O2 drop impact; Stage II: inertial spreading of H2O2 drop over CPSE pellet; Stage III: onset of exothermic decomposition reaction H2O2 droplet by Mnacac particles which leads to the formation of aerosol; Stage IV: local explosion of aerosol and ignition of CPSE pellet occur results in two types of aerosol-CPSE fuel interaction; Stage V: a weak self-sustained flame from CPSE fuel. A key finding of the study reveals that a minimum catalyst concentration ( [ C ] M n 3 + , L ) is required to ignite CPSE fuel using H2O2 and ID decreases with an increase in the [ C ] M n 3 + . Similarly, there exists an upper catalyst loading ( [ C ] M n 3 + , U ) above which ID is increased due to the increase in Mnacac particle size by agglomeration. [ C ] M n 3 + , L and [ C ] M n 3 + , U depends on the type and concentration of the gellant and the availability of active hydroxyl (–OH) group in the gellant. Finally, SEM-EDS analysis of the residue indicates the formation of oxides of manganese with a small amount of carbon (~1.66 to 2.53 wt%), hinting complete combustion of the gellant particles.

中文翻译：

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混合火箭用过氧化氢固化乙醇燃料自燃延迟研究

摘要 使用火箭级过氧化氢（90% RGHP；H2O2）作为有机胶凝剂，即甲基纤维素 (MC) 和羟丙基甲基纤维素 (HPMC) 配制的催化固化乙醇 (CPSE) 的自燃相互作用和点火延迟时间已被研究。一种氧化剂，用于混合火箭发动机。使用等转化弗里德曼方法，发现卸载的固化乙醇样品的表观活化能 (Ea) 在 9.06–14.01 kJ/mol 的范围内。使用跌落测试方法使用乙酰丙酮锰 (III) (Mnacac) 作为催化剂研究了含 H2O2 的 CPSE 燃料的自燃延迟 (ID)，发现 ID 位于 49-307 ms 的范围内。根据来自高速相机、光电二极管、和从跌落测试中获得的麦克风。阶段 I：在 H2O2 下落撞击之前；第二阶段：H2O2 滴在 CPSE 颗粒上的惯性扩散；第三阶段：Mnacac 颗粒开始放热分解反应 H2O2 液滴，导致气溶胶的形成；第四阶段：气溶胶的局部爆炸和 CPSE 颗粒的点火导致两种类型的气溶胶-CPSE 燃料相互作用；阶段 V：来自 CPSE 燃料的微弱自持火焰。该研究的一个关键发现表明，使用 H2O2 点燃 CPSE 燃料需要最低催化剂浓度 ([C] M n 3 + , L)，ID 随着 [C] M n 3 + 的增加而降低。类似地，存在催化剂载量上限（[C] M n 3 + , U ），高于该上限，由于附聚导致 Mnacac 粒径增加，ID 增加。[ C ] M n 3 + , L 和 [ C ] M n 3 + , U 取决于胶凝剂的类型和浓度以及胶凝剂中活性羟基 (-OH) 基团的可用性。最后，残留物的 SEM-EDS 分析表明锰的氧化物与少量碳（~1.66 至 2.53 wt%）形成，暗示胶凝剂颗粒完全燃烧。