REGULARITIES OF THE COMBUSTION PROCESS OF METALLIC FUEL PARTICLES IN THE DECOMPOSITION PRODUCTS OF PYROTECHNIC MULTICOMPONENT NITRATE-METALLIZED MIXTURES
Authors: Kozyar Nazariy , Kyrychenko Oksana , Vaschenko Vyacheslav , Shkoliar Ievhenii , Kutsenko Mariia , Tomenko Maryna , Honchar Serhii , Kolinko Serhii 
Published: January 2025

Purpose. The analysis and identification of regularities of the combustion process of magnesium particles in active gaseous products of thermal decomposition of nitrate-containing oxidizers and additives of the specified substances for determining the fire-hazardous properties of pyrotechnic mixtures under external thermal conditions .

Methods. Modern methods of physical and chemical analysis: thermocouple methods of temperature measurement (tungsten-rhenium thermocouples were used); non-contact methods of recording the beginning and end of the burning of metal particles (temperature indicators, photosensitive elements, etc.); film shooting methods (film camera “Konvas-auto” (shooting speed 30 frames/s)) and methods of micro-filming SKS-1M film camera (shooting speed 3000…5000 frames/s)) of the burning process of individual metal particles; methods of X-ray structural and micro-X-ray spectral analysis (MRSA) for chemical analysis.

The results. Data on the combustion of magnesium particles in active gaseous products of thermal decomposition of nitrate-containing oxidizers, organic and inorganic substances are systematized and summarized. It was found that the combustion of magnesium particles is highly complex, occurring through a diffusion mechanism influenced by a variety of factors. Additionally, the combustion of magnesium ribbons in a mixture of oxygen and inert gases occurs in eight distinct regions, each with characteristic flame features that depend on oxygen concentration and external pressure. It was established that magnesium particles burn in oxygen-containing media in the diffusion mode with the formation of a bright glow zone, the radius of which increases with increasing oxygen concentration and external pressure.

Scientific novelty. For the first time, regularities of the combustion process of magnesium particles in active gaseous products were established (О2, О2 + N2, air, СО2, water vapor, etc.) thermal decomposition of nitrate-containing oxidants (О2, О2 + N2, air, СО2, water vapor etc.) and additives of organic substances (paraffin, stearin, iditol, thiocol, etc.) and inorganic substances (metal fluorides and oxides, etc.) to determine the fire-hazardous properties of pyrotechnic mixtures under conditions of external thermal effects.

Practical significance. The theoretical and experimental results, presented as mathematical models and a database of experimental data, demonstrate the influence of technological parameters of mixture charges on the critical modes of explosive combustion under external thermal conditions (elevated temperatures, external pressures, etc.). These results enable the optimization of technological parameters (e.g., component ratios, dispersion of metallic fuel) during product manufacturing, increasing ignition temperatures and reducing the likelihood of fire-explosive destruction during storage, transportation, and product use under thermal conditions.

Key words: pyrotechnic multi-component nitrate-metallized mixtures, fire safety, metal fuels, combustion processes.