High Test Peroxide (HTP) is a well-known green and energetic material, widely used in propulsion systems in a variety of applications, including hypergolic systems. This experimental work mixed fumed silica with liquid HTP to synthesize Gelled HTP (GHTP). A high-speed camera and a time-resolved infrared camera were employed to analyze liquid/gel phase mixing, ignition, and flame spread through drop tests, adopting a promising low toxicity liquid fuel as a GHTP hypergolic pair. Liquid/gel impinging jets in ambient air were also performed, simulating a basic element of a hybrid liquid/gel propulsion system. Prior to ignition, GHTP revealed a lower mixing ratio compared to HTP, which ultimately led to an ignition delay time of 20.6 ±6.4 ms, while HTP reached 14.6 ±3.7 ms when 1 wt% of catalyst was used. The flame area, used as a parameter to quantify gas-phase reaction, also showed sensitivity to liquid/gel phase mixing. Using a less concentrated HTP solution, ignition of GHTP/liquid fuel seemed to occur around 6 s faster than liquid HTP/liquid fuel in impinging jets, probably due to differences in propellant residence time and the vapor formation process. A theoretical performance analysis considering GHTP as an oxidizer in a hybrid liquid/gel hypergolic system revealed that the gelled propellant, made with the addition of 6 wt% of fumed silica, can achieve 96% of liquid HTP’s specific impulse with the selected fuel. Furthermore, the theoretical density specific impulse of the hybrid gel/liquid system would significantly surpass that of the liquid/liquid system if 10 wt% of aluminum were mixed with GHTP. To take advantage of the hybrid system, a new propulsion system composed of pistons coupled to propellant tanks is proposed to properly infuse the gelled and liquid propellants. The results from this experimental work, together with theoretical analysis, suggest that the hybrid liquid/gel system may be suitable for military applications.

中文翻译：

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凝胶过氧化氢：通过跌落和撞击射流测试与低毒燃料发生自燃反应


高测试过氧化物 (HTP) 是一种众所周知的绿色高能材料，广泛用于各种应用的推进系统，包括自燃系统。本实验工作将气相二氧化硅与液体 HTP 混合合成凝胶 HTP (GHTP)。采用高速摄像机和时间分辨红外摄像机通过跌落测试分析液/凝胶相混合、点火和火焰传播，采用有前途的低毒液体燃料作为 GHTP 自燃对。还进行了环境空气中的液体/凝胶撞击射流，模拟了混合液体/凝胶推进系统的基本元件。在点火之前，GHTP 与 HTP 相比显示出较低的混合比，最终导致点火延迟时间为 20.6 ±6.4 ms，而当使用 1 wt% 催化剂时，HTP 达到 14.6 ±3.7 ms。火焰面积用作量化气相反应的参数，也显示出对液体/凝胶相混合的敏感性。使用浓度较低的 HTP 溶液，在撞击射流中，GHTP/液体燃料的点火似乎比液体 HTP/液体燃料快 6 秒左右，这可能是由于推进剂停留时间和蒸气形成过程的差异。将 GHTP 作为液体/凝胶混合自燃系统中的氧化剂进行的理论性能分析表明，添加 6 wt% 气相二氧化硅制成的凝胶推进剂在所选燃料下可达到液体 HTP 96% 的比冲。此外，如果 10 wt% 的铝与 GHTP 混合，混合凝胶/液体系统的理论密度比冲将显着超过液体/液体系统的理论密度比冲。 为了利用混合系统的优势，提出了一种由连接到推进剂罐的活塞组成的新推进系统，以正确注入凝胶和液体推进剂。这项实验工作的结果以及理论分析表明，混合液体/凝胶系统可能适合军事应用。