Analysis of agglomeration behaviors of aluminized composite propellants

Abstract

To improve the performance of aluminized propellants, it is important to study the mechanism of agglomeration and approve the methods of inhibiting agglomeration. In this study, organic fluoride was added to the propellants and the dynamic combustion process of the propellants was obtained through visual combustion test system. At the same time, an algorithm which can detect the size of particles out of focus more accurately is also proposed. Then, the agglomeration behaviors, as well as the size distribution of initial condensed products and final condensed products, during the combustion of propellants are discussed. The influence of organic fluoride additive on the evolution of condensed products and the distribution of their sizes were also analyzed. The results show that the condensed products had a coral structure, and underwent the stages of exposure, accumulation, splicing, separation, and combustion to evolve into oxidation cap structures. When organic fluoride is added, special flocculent products were formed instead of coral-like products and the AlF3 was found in the condensed products. Besides, detailed behaviors of condensed products have been found in the gas. The products with an oxidation cap still subsequently interacted with one another in the gas, including through re-fusion and re-separation. The distribution of the initial products was relatively concentrated and stable while that of the final products exhibited a prominent trend of increasing first, then decreasing, and gradually stabilizing. Besides, with the addition of organic fluoride, the main combustion products were converted α - Al2O3 and θ - Al2O3 to γ - Al2O3 and δ - Al2O3, indicating that the addition of organic fluoride significantly improved the performance of the aluminized propellants in terms of suppressing the size of the condensed products.