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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.i1-6.90
pages 70-80

MECHANISTIC STUDIES OF LOW-PRESSURE FLAMES SUPPORTED BY NITROGEN OXIDES

J. J. Cor
Center for Combustion Research, University of Colorado, Boulder, Colorado, USA
C. B. Dreyer
Center for Combustion Research, University of Colorado, Boulder, Colorado, USA
M. C. Branch
Center for Combustion Research, University of Colorado, Boulder, Colorado, USA

Краткое описание

The development of detailed models of solid propellant combustion requires detailed information on the gas-phase chemistry occurring above the propellant surface. Different flame systems have been identified as important to study in order to gain greater understanding of solid propellant gas-phase chemistry. In particular, systems which need study are flames of carbon monoxide and hydrocarbons burning with nitrogen oxides. Since both premixed and diffusion flame chemistries exist above the propellant surface, premixed and diffusion flames involving these reactants need to be studied. In the past decade, several experimental studies have been made of premixed flames consisting of these reactants. More recently, counterflow diffusion flames consisting of these reactants have been studied as well. In the present work, several different premixed and counterflow diffusion flames have been modeled using a common, 275-reaction mechanism.
Solid propellant combustion models require gas-phase chemical kinetic mechanisms which are as small as possible. Therefore, for each premixed flame system studied, sensitivity and rate generation analyses have been used to identify which reactions in the detailed mechanism are critical to each system. Based on these analyses, and comparisons with the experimental data, reduced mechanisms, consisting of only the essential chemical reactions for each flame system, have been developed. These reduced mechanisms have been combined into a comprehensive, reduced mechanism consisting of 42 reactions. In general, this reduced mechanism models the flames' chemistry as accurately as the full mechanism does.
The full and reduced mechanisms have also been used to model methane-nitrous oxide and carbon monoxide-nitrous oxide counterflow diffusion flames. From comparisons with the experimental data, it is determined that, in general, the full mechanism and the reduced mechanism model the diffusion flame chemistry as accurately as they modeled the premixed flame chemistry. Also, in the diffusion flames, there is reasonable agreement between the modeling results using the full and reduced mechanisms.
The problem of N2O decomposition remains a key area requiring further study. The rate constants for this reaction had to be modified to model the CO-N2O flames and the CH4-N2O diffusion flame accurately. The reason for this discrepancy is still to be determined, but future studies of the N2O decomposition reaction are suggested.


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