Development of a mathematical model of the internal structure of a granular heat accumulator for launching a mono-fuel gas generator

The issue of improving energy-mass characteristics is one of the most important ones in the development of gas generators for various purposes. In this regard, as part of the search for ways to use promising types of fuels, experimental studies of gas generators operating on composite mono-fuel based on nitrate esters were carried out. As a device initiating the combustion reaction, a granular self-heating heat accumulator was used, which was placed in a cylindrical combustion chamber. Experimental studies made it possible to reveal the features of a complex and multi-stage process of mono-fuel conversion occurring in the pore space of the gas generator combustion chamber on the surfaces of the granules and inside a complex system of channels consisting of elementary cells formed by these granules. In this case, the pore space of the heat accumulator is granular filling of mono-dispersed granules of a disordered structure. The task of the work described in the article was to create a mathematical description of granular filling of a disordered structure, solved in a two-dimensional formulation. The article proposes a method of transition from hexagonal stacking to conditionally ordered one that combines the compactness of hexagonal stacking and the ease of description of cubic stacking. The resulting stacking makes it possible to represent half of the frontal section of the granular heat accumulator in the form of a vertical flat layer with a given structure determined by porosity, granule diameter and dimensions of the combustion chamber – its length and diameter. The proposed approach for the transition from a disordered filling structure to a conditionally ordered structure made it possible to develop a mathematical model that describes the internal structure of the launch heat accumulator and determine the coordinates of the heat accumulator zones in which various stages of monopropellant conversion take place. This will allow us to proceed to the formation of a description of the working process of gas generators with a granular self-heating heat launch accumulator.