DETERMINATION OF CRITICAL VALUES OF PARAMETERS OF EXTERNAL THERMAL EFFECTS ON PYROTECHNIC PRODUCTS BASED ON NITRATE-METAL MIXTURES IN THE CONDITIONS OF THEIR STORAGE AND TRANSPORTATION

Abstract

The properties of pyrotechnic products for various purposes (signaling and tracing devices, pyrotechnic flares, rocket and space technology elements, etc.) based on multicomponent compacted mixtures of metal propellants powders (magnesium, aluminum, aluminum-magnesium alloys (AMA), etc. ), nitrate-containing oxidizers (nitrates of alkali and alkaline earth metals, etc.) and additives of various organic (paraffin, stearin, naphthalene, anthracene, urotropin, iditol, etc.) and inorganic substances (metal fluorides, etc.). It has been established that during storage and transportation, they can be exposed to intense external thermal effects (e.g., fires in warehouses where products are stored, fires in nearby flammable objects, in combat zones, etc. ), resulting in premature ignition of the charges of the mixtures, which leads to the destruction of products with the formation of high-temperature combustion products (up to 3000...4000 K), which fly in different directions and pose a fire hazard to surrounding objects (fuels and lubricants, wooden buildings, launchers with service personnel, etc.)

Mathematical models of external thermal effects on the surface of charges of nitrate-metallized mixtures with additives of organic and inorganic substances for pyrotechnic products for various purposes in storage or transportation conditions have been developed, taking into account the geometric shape of the charges (flat plates, cylindrical rods and hemispherical elements); thermomechanical properties and technological parameters of the mixture; temperature dependences of the thermophysical properties of the mixtures.

The temperature distributions in the charges of the mixtures were calculated and the critical values of the external heat flux and its action time were determined, the excess of which leads to premature ignition of the charges of the mixtures, explosive development of their combustion and, ultimately, to the fire-hazardous destruction of pyrotechnic products and surrounding objects.