Optimization of interface conditions in the case of laser diode ignition of pyrotechnic mixtures

Ignition. by laser diode, of explosive reactions on pyrotechnical mixtures is presented in this paper. A model was studied in order to determine the i gnition threshold energy of the pyrotechnic compositions. It results in a n umerical solution of the heat equation, in transient, with a source term du e to the in-depth absorption of the laser radiation. The chemical reaction is modelled by the way of a kinetic law based upon an Arrhenius law. In ord er to take into account this interface phenomenon, a thermal resistance R-c of contact was introduced at the interface sapphire windows-pellet. In thi s article, we propose to optimize this term and the depth mu of absorption of the laser radiation, in order to minimize the deviation from the experim ental results. We thus obtain the value of R-c and of mu. While varying var ious parameters (density of power, porosity, percentage of carbon black), t he adequacy of calculations and the experimental results will be highlighte d. Based on the results obtained we show in Fe/KClO4 mixture that the energ y threshold is controlled more particularly by the conditions of the interf ace represented by the thermal resistance of contact R, and coefficient of absorption mu.