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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.v5.i1-6.290
pages 274-283

ACOUSTIC EMISSION OF UNDERWATER BURNING SOLID ROCKET PROPELLANTS

S. Rampichini
Laboratorio di Termofisica, Dipartimento di Energetica Politecnico di Milano, 20133 Milan, MI, Italy
D. Ruspa
Laboratorio di Termofisica, Dipartimento di Energetica Politecnico di Milano, 20133 Milan, MI, Italy

Краткое описание

Samples of an ammonium perchlorate-based composite solid propellant (AP-HTPB) were ignited and burned in a combustion chamber, filled with water, and pressurized by gas (air or nitrogen) under pressures up to 20 atm. Low frequency (< 3.5 kHz) spontaneous acoustic emission from the combustion process was picked up by a submerged microphone and handled by common electronic circuitry. The acoustic combustion signal was first analyzed in the time domain to obtain information about steady burning rates. Notches purposely cut on the propellant strand can easily be identified by inspecting the sound emission trace. Steady burning rates measured by different acoustic techniques show no appreciable differences with respect to standard techniques (video recording and fuse wires) implemented for combustion under water or nitrogen. The acoustic combustion signal was also studied in the frequency domain and its dependence on mass burning rate experimentally deduced. By a spectrogram analysis, important features of the whole combustion process (including ignition delays, burnouts, and local extinctions) can be studied.