Shock compression of liquid hydrazine

Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used by the Air Force and NASA for aerospace propulsion and power systems. Because the propellant modules that contain the hydrazine can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted in an attempt to investigate the detonability of liquid hydrazine; however, the experiments results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. We also present the methodology of our approach, which includes chemical kinetic experiments, chemical equilibrium calculations, and characterization of the equation of state of liquid hydrazine

Etude de la transition choc-détonation du nitrométhane par spectrométrie d'émission

This study is part of a research program on the detonation of high explosives. The objective of this work is to clarify the mechanism of shock initiation of nitromethane (NM), by spectral analysis in the range 0.3-0.85 µm. NM is a liquid explosive, transparent in the visible and near-infrared range. The experiments consist in plane shock impact on explosive targets at 8.6 GPa. Time-resolved radiance profiles and intensity spectra show that chemical species have several optical characteristics depending on the phases of the shock to detonation transition. Shocked NM remains transparent and its temperature is higher than 2500 K because of local chemical reactions. The reactions products produced during the superdetonation formation are semi-transparent: they are optically thick for wavelengths higher than 0.6 µm. The study shows that detonation products behind the detonation wave do not behave like a blackbody in the visible range. Detonation products are semi-transparent and optically thick. A model for the absorption coefficient is proposed for a water vapour and carbon clusters mixture. It is based on a Rayleigh scattering regime and equation of radiative tranfer (ERT) for an emitting and absorbing medium. The resolution of the ERT for semi-transparent gases by an inversion method enables to determine the temperature profiles in the explosive. The method is tested on simple cases of detonation.Ce travail de thèse porte sur l'étude des mécanismes d'amorçage par choc du nitrométhane (NM), explosif liquide, transparent dans le domaine visible et dans le proche infrarouge. Afin de réaliser l'analyse spectrale des produits de réaction du NM en vue de déterminer les profils de température, un banc de spectrométrie d'émission a été mis au point dans le domaine UV-Visible 0,3-0,85 µm. Des essais d'impacts plans à 8,6GPa ont été réalisés. L'étude temporelle et spectrale de la luminance émise durant la TCD montre que les milieux en présence présentent différentes caractéristiques optiques. Le NM sous choc est transparent alors que la température de luminance mesurée est de 2500K, du fait de la présence de réactions chimiques localisées. Les espèces chimiques produites lors de la formation de l'onde de superdétonation constituent un milieu semi-transparent, milieu optiquement mince aux courtes longueurs d'onde, inférieures à 0,6 µm et optiquement épais pour les longueurs d'onde comprises entre 0,6 et 0,85 µm. En détonation quasi-stationnaire, l'étude spectrale dans le domaine visible montre que les produits de détonation n'ont pas le comportement d'un corps noir, mais celui d'un milieu semi-transparent et optiquement épais. Un modèle d'absorption est proposé sur la base d'un milieu constitué de vapeur d'eau et de particules de carbone qui suivent le régime de diffusion Rayleigh. A partir des mesures de luminance, l'inversion mathématique de l'équation de transfert radiatif d'un milieu semi-transparent homogène et non diffusant permet de retrouver les profils de température dans l'épaisseur d'explosif. Elle est validée sur des cas synthétiques de détonation

Indexes of the Proceedings for the Ten International Symposia on Detonation 1951-93

The Proceedings of the ten Detonation Symposia have become the major archival source of information of international research in explosive phenomenology, theory, experimental techniques, numerical modeling, and high-rate reaction chemistry. In many cases, they contain the original reference or the only reference to major progress in the field. For some papers, the information is more complete than the complementary article appearing in a formal journal; yet for others, authors elected to publish only an abstract in the Proceedings. For the large majority of papers, the Symposia Proceedings provide the only published reference to a body of work. This report indexes the ten existing Proceedings of the Detonation Symposia by paper titles, topic phrases, authors, and first appearance of acronyms and code names