Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Central European Journal of Energetic Materials

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Effect of Aluminum Content on the Combustion Performance of HTPB/AP/Al Propellants under High Combustion Pressure

Han Jin-chao, Hu Song-qi, Chu Cheng-long, Liu Lin-lin

Central European Journal of Energetic Materials

2023

Vol. 20, no. 1

14--35

Combustion mechanisms of propellants under high combustion pressure are extremely important for the development of high-pressure solid rocket motors. The combustion characteristics of three HTPB propellants prepared with an aluminum content of 1%, 10%, and 18% were evaluated in this study by analyzing the extinguished propellant surface, the combustion flame, and the temperature profile in the combustion pressure range of 12-30 MPa. The results showed that the burning surface temperature of the three propellants increased from 425 to 535 and to 643 ℃ as the aluminum content was increased from 1% to 18%, resulting in a faster thermal decomposition rate of the binder than the thermal decomposition rate of the AP particles. Consequently, the morphology of the extinguished propellant surface evolved from concave into convex, and the higher the aluminum content, the more obvious became the convex morphology. The combustion flame height of the three propellants showed a downward trend when the combustion pressure was increased from 12 to 18 MPa, enhancing the heat feedback to the burning surface. The burning surface temperature of the three samples increased by 75, 105 and 189 ℃, respectively, with the increase in combustion pressure, resulting in a more distinct degree of concave and convex morphology of the extinguished propellant surface. In addition, this demonstrated that the local heat and mass transfer might play a dominant role under high pressures.

Effects of Metal Oxides on the Thermal Decomposition Kinetics and Mechanisms of HAN/PVA Based Propellants

Hu Song-qi, Liu Xue-li, Liu Lin-Lin, Kang Bo, Zhang Yan

Central European Journal of Energetic Materials

2021

Vol. 18, no. 3

322-338

The thermal decomposition processes of HAN/PVA-based propellants have been investigated using a simultaneous thermogravimetric analysis (TGA) – differential scanning calorimetry (DSC), coupled with Fourier-Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (MS) system. The activation energy (Ea), pre-exponential factor A and reaction mechanism function f(α) of the decomposition processes have been determined by non-isothermal and Malek methods. The results showed that the decomposition process of an HAN/PVA sample occurs mainly in the temperature range 202.2~220.1 °C, with a mass loss, heat release and Ea of about 84.8%, 1474.18 and 88.76 kJ·mol–1, respectively. Of the seven metal oxides studied as catalysts, Al2O3, V2O5 and Fe2O3 have significant catalytic effects on an HAN/PVA-based propellant, in lowering the decomposition temperature, with Ea changing from 88.8 to 83.7, 85.6 and 113.6 kJ·mol–1, respectively. The f(α) of both HAN/PVA and HAN/PVA/Al2O3 samples can be expressed as f(α) = (1 – α)2, whereas f(α) = α or f(α) = α/2 fit well for the HAN/PVA/V2O5 and HAN/PVA/Fe2O3 samples.