THEORIE DE LA DETONATION IDEALE. EXPLOSIFS NON-IDEAUX ET REGIMES DE DETONATION NON-IDEALE

Dans une première partie, on présente le modèle de la détonation idéale en insistant sur les hypothèses physiques qui président à la résolution des équations de la mécanique des milieux continus. L'exposé du principe du calcul des caractéristiques de la détonation idéale est suivi de celui de l'état actuel de la confrontation prévision numérique - expérience dans le domaine des explosifs condensés. La deuxième partie est consacrée à la détonation en cartouche cylindrique de diamètre fini prise comme exemple d'un régime de détonation non-idéale stationnaire et comme introduction au rôle des hétérogénéités physiques sur les processus d'excitation des réactions chimiques. Une approche semblable appliquée à la construction de la détonation sera présentée à la suite de cet exposé par le Dr. NUNZIATO. Dans une troisième partie, on examinera quelques cas de compositions non-idéales, leur détonation dans des géométries non-idéales et on en conclura à l'importance d'une meilleure connaissance des mécanismes réactionnels.In a first part is presented the model of the Ideal Detonation. Emphasis is placed on the physical assumptions made in the setting and resolution of the continuum mechanics equations to be used. The basic elements of the Ideal Detonation parameters computations as well as the results achieved so far in comparing the numerical predictions with the experimental findings in the case of the condensed explosives will be reported. The second part will concern the detonation of cylindrical cartridges of a limited diameter taken as an example of a non-ideal stationnary detonation. The role played by the physical heterogeneities on the conditions for the detonation propagation is examined. A similar approach is to be found in NUNZIATO presentation. In a third part, we will review some non-ideal explosives compositions as well as their behavior in non-ideal geometries. As a conclusion, we emphasize the need for a better knowledge of chemical reactions processes

Classical Theory of Detonation

In a first part is presented the model of the Ideal Detonation. Emphasis is placed on the physical assumptions made in the setting and resolution of the continuum mechanics equations to be used. The basic elements of computations of ideal detonation parameters will be described. The experiments performed to check the predictions, and their results, will be reported. Some discussion of explosives in which chemical equilibrium is not reached, due to slow diffusive mixing of the reactants or to conditions where some of the reactions are very slow, will also be given. These explosives are often called non-ideal explosives. Obviously, when the reaction zone is not very thin relative to system dimensions, or when it is not very short relative to system times, the Ideal Detonation model, restricted to plane, steady flow, is inadequate. The third part of the paper is concerned with curved detonation fronts, and with time dependent processes. The steady detonation of small-diameter cylindrical cartridges will be discussed as one example, and the initiation of detonation in the shock-to-detonation transition as another. Detonation theory is not a closed subject, and much effort is currently being spent to extend classical theory. Some of the newer ideas will be introduced in a concluding part