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Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
International Journal of Energetic Materials and Chemical Propulsion
ESCI SJR: 0.149 SNIP: 0.16 CiteScore™: 0.29

ISSN Печать: 2150-766X
ISSN Онлайн: 2150-7678

International Journal of Energetic Materials and Chemical Propulsion

DOI: 10.1615/IntJEnergeticMaterialsChemProp.v4.i1-6.650
pages 693-705

EXPERIMENTAL STUDIES OF ALUMINUM AGGLOMERATION IN SOLID ROCKET MOTORS

J. Duterque
Energetics Department ONERA - FRANCE

Краткое описание

In a solid propellant containing an inert binder (polybutadiene), an oxidizer (ammonium perchlorate) and aluminum (15/ 20%), Al is introduced during the propellant formulation as single particles, the median diameter of which is typically between 5 and 40 microns. During the propellant combustion, some of the aluminum particles leave the combustion surface without agglomeration, while others coalesce and give globules, with diameters very different from the initial particle sizes. The relative proportions of unagglomerated particles and globules are poorly known.
The diameter and the mass fraction of large globules which leave the combustion surface immediately govern the Al combustion time and the diameter and mass fraction of the large Al2O3 caps. Understanding of this last point is essential for large motors because these residues are liable to form Al2O3 slag which accumulates at the motor aft end.
The experimental set-up is a pressurizable bomb (<10 MPa). The sample combustion surface is filmed with a high speed camera (≈ 2000 f/s). Film utilization allows the determination of Al globule diameters just before ignition. For a classical composite propellant, a median value of 125 μm was found, the combustion pressure being 4 MPa. By modifying some parameters (propellant formulation, combustion pressure), some factors able to modify the globule size were determined.