Defining the acceptable heating mode pyrotechnic mixture at their operation

At the stage of designing and developing pyrotechnic mixtures, one must be able to predict the permissible modes of their heating, the excess of which leads to the ignition of charges of mixtures under metal shells of products, acceleration of their combustion with increasing heating temperatures and external pressures, which ultimately leads to fire explosives for surrounding objects destruction of mixtures. The purpose of this work is to construct mathematical models of heating pyrotechnic mixtures with external heat sources and to develop methods for determining acceptable ranges of changes in their parameters, which do not lead to fire explosive fracturing of mixtures. The refined mathematical model of heating of pyrotechnic mixtures with external thermal flow is developed, taking into account the temperature dependences of the thermophysical properties of the shell material and the charge of the mixture (volumetric heat, heat transfer coefficient) and allows more accurately calculate the temperature distribution along the thickness of the product. It was established that an increase in the value of the heat flux leads to an increase in the temperature of the lower surface of the shell that is in contact with the charge of the mixture. For the first time, the maximum allowable values of the parameters of thermal influences on the surface of metal shells of pyrotechnic mixtures, excess of which leads to intensive self-heating of the reactive mixture, up to its ignition and acceleration of combustion, which ultimately leads to fire-explosive fracturing of mixtures