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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.i1-6.1040
pages 1018-1027


Claudio Zanotti
TEMPE - National Research Council Via Cozzi 53, 20125 Milano, Italy
Piero Giuliani
TEMPE - National Research Council Via Cozzi 53, 20125 Milano, Italy
Masahiro Kohno
Institute of Space and Astronautical Science, 3-1-1 Yoshinodai Sagamihara, Kanagawa 229, Japan

Краткое описание

The solid rocket motors for high altitude applications operate under external vacuum conditions and for that reason, during their life, the inner motor pressure can reach values, which are lower than the measured Pressure Deflagration Limit (PDL) in laboratory tests. Although this condition should not allow any combustion process inside the motor, a small residual thrust is still active due to unexpected gases production. The motor's operating time becomes longer than the estimated one, and therefore this occurrence cannot be neglected in the motor design. The thermal insulator degradation, coupled to the propellant combustion or high temperature decomposition at pressures below the PDL, can be the main causes of this unpredicted motor performance. For those reasons, an experimental study to analyze the wall-effect due to the thermal protection presence, in contact with the burning propellant, has been carried out in order to find out which parameters are more sensible to this operating configuration. Results have demonstrated that the average propellant temperature increases when the burning surface approaches the thermal insulator because of the large value of the thermal wave thickness, especially when metallized propellents are used. Moreover, the radiant energy scattered by the inner part of the nozzle, or by the exposed thermal protection, is another possible cause that yields the propellant to bum, or gasify, below PDL. To verify this possibility, the degradation behavior of the thermal protections has been analyzed and results indicate that the energy amount emitted by these hot materials is enough to sustain the propellant combustion process below PDL.