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Liang D.,Zhejiang University | Liu J.,Zhejiang University | Xiao J.,Institute of Aerospace Chemotechnology | Xi J.,Zhejiang University | And 3 more authors.
Acta Astronautica | Year: 2015

The microstructure of amorphous boron and the primary combustion products of boron-based fuel-rich propellant (hereafter referred to as primary combustion products) was analyzed by scanning electron microscope. Composition analysis of the primary combustion products was carried out by X-ray diffraction and X-ray photoelectron spectroscopy. The energy release properties of amorphous boron and the primary combustion products were comparatively studied by laser ignition experimental system and thermogravimetry-differential scanning calorimetry. The primary combustion products contain B, C, Mg, Al, B4C, B13C2, BN, B2O3, NH4Cl, H2O, and so on. The energy release properties of primary combustion products are different from amorphous boron, significantly. The full-time spectral intensity of primary combustion products at a wavelength of 580 nm is ~2% lower than that of amorphous boron. The maximum spectral intensity of the former at full wave is ~5% higher than that of the latter. The ignition delay time of primary combustion products is ~150 ms shorter than that of amorphous boron, and the self-sustaining combustion time of the former is ~200 ms longer than that of the latter. The thermal oxidation process of amorphous boron involves water evaporation (weight loss) and boron oxidation (weight gain). The thermal oxidation process of primary combustion products involves two additional steps: NH4Cl decomposition (weight loss) and carbon oxidation (weight loss). CL-20 shows better combustion-supporting effect than KClO4 in both the laser ignition experiments and the thermal oxidation experiments. © 2015 IAA. Source


Liang D.,Zhejiang University | Liu J.,Zhejiang University | Xiao J.,Institute of Aerospace Chemotechnology | Xi J.,Zhejiang University | And 2 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

The application of a metal additive is an effective way to improve the performance of B-based propellants. This study focused on the effect of metal additives on the energy release properties of primary combustion products of B-based propellants (hereafter referred to as primary combustion products) to facilitate an understanding of the stages of the secondary combustion of B-based propellants. Mg-Al alloy (MA), Mg metal, Al metal, and Ti metal were used to prepare the primary combustion product samples. A comparative analysis was also made of samples (with MA) obtained under different gas generator pressures. X-ray diffraction, X-ray photoelectron spectroscopy, and inductively coupled plasma chromatography were used to analyze the sample components. The ignition, combustion, and thermal oxidation properties of the samples were studied with a laser ignition experimental system and a thermobalance, respectively. The primary combustion product samples mainly contained C, B13C2, B4C, B2O3, H3BO3, NH4Cl, BN, B, and their respective metal additives. The degree of primary combustion of the samples increased with the gas generator pressure. The presence of MA effectively increased the combustion intensity of the samples. The average combustion temperature of the samples with added MA reached 1440.36 °C. The ignition delay time of the samples ranged between 61 and 146 ms. The self-sustaining combustion time of the samples ranged between 1174 and 1254 ms. MA and Ti both helped to shorten the ignition delay time and prolong the self-sustaining combustion time. The samples obtained under higher gas generator pressures exhibited inferior combustion characteristics. MA decreased the initial oxidation temperature of C (492.6 °C), and Ti decreased the initial oxidation temperature of B (738.1 °C). Mg could improve the oxidation efficiency of B at high-temperature conditions. Among the four metal additives, MA was the most beneficial to the energy release of the primary combustion products, whereas Al had the weakest effect. © 2015 Akadémiai Kiadó, Budapest, Hungary. Source


Ren X.-T.,Institute of Aerospace Chemotechnology | Du T.,Hubei Hangpeng Chemical Power Technology Ltd. | He J.-X.,Institute of Aerospace Chemotechnology | Lu Y.-H.,Institute of Aerospace Chemotechnology | And 4 more authors.
Hanneng Cailiao/Chinese Journal of Energetic Materials | Year: 2015

Bis(2, 2, 2-trinitroethyl)amine(BTNA) was synthesized according to literatures and characterized by elemental analysis, infrared radiation and differential scanning calorimetry. Using Growth Morphology methods contained in Morphology module of Materials Studio 6. 0, the crystal morphology and crystallization behavior of BTNA were calculated, and the relationship between the structures of important crystal faces and media of crystalization were analyzed. Theoretical research shows that the face (111) is the most important crystal surface if crystallization was carried out in the solvents with strong polarity. The ratio of appearance area of (002), (102) and (020) increases, and the importance of faces (200) and (021) decreases. While the importance of weak polar surface will increase in non-polar or weak polar solvents. By recrystallizing BTNA from dichloromethane (weak polar solvent), it is found that the crystalloid is more uniform and the aspect ratio is smaller compared with that from water, which indicates that the experimental result is consistent with the simulation ones. ©, 2015, Institute of Chemical Materials, China Academy of Engineering Physics. All right reserved. Source

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