Using the group analysis transfer operator in the method of similarity for studying the fuel combustion process in engines

In this paper, we study modelling of the process of combustion of small quantities of a pyrotechnic mixture based on potassium perchlorate and aluminium powder in impulse devices (engines). The analysis of combustion processes includes an introduced general criterion (prime criterion) of similarity composed of Wobbe numbers that are determined for the engine and its model in the course of theoretical studies or experiments. Research data show that the transfer operator in the field of group theory is mostly used for describing the process of combustion of metallized pyrotechnic mixtures.

SUGGESTIONS ON AMENDING THE METHODOLOGY OF ESTABLISHING THE OBJECT BELONGING TO FIREAREMS AMMUNITION AND ITS SUITABILITY FOR FIRING

The article considers structural features of certain types of cartridges in relation to firearms, as well as non-combat cartridges, auxiliary cartridges and products that are structurally similar to cartridges, which are submitted for research as part of forensic firearm examination, especially in connection with the ongoing war in Ukraine, occupation of part of its territory and as a result with mass distribution of illegal weapons and ammunition in Ukraine. The article outlines problematic issues of dismantling cartridges in relation to small arms of large caliber, cartridges loaded with special bullets, particular types of silent bullets, non-combat cartridges. The article also highlights issues of optimizing actions of a forensic expert while research, the objects of which are products that are structurally similar to small arms cartridges, but loaded with propellants, pyrotechnic mixtures, poisonous substances, along with products that coincide with small arms cartridges in size and partially in design. Backlog of approaches incorporated in the current methodology for researching ammunition is identified in the article and practical need for updates and additions is actualized. Proposals were raised to amend the Methodology aimed at increasing safety of forensic firearm examinations, regulating actions of a forensic expert in deciding on dismantling cartridges. It is suggested to use modern devices for reloading cartridges in forensic practice to provide a better and safer research. A procedure for a forensic expert course of action while study of cartridges which are sent for forensic examination in a single copy to minimize the impact on both the object under study and its components, is proposed.

New Technologies in the Production of Thermal Chemical Current Sources

It is proposed to use Li4Si alloys with Li content > 50 wt.% as anode materials. A technology for the synthesis of Li4Si in a pre-formed anode with thermal interaction Li with Si-containing composite material has been developed. It is proposed to use FeS2 as a cathode, which has a high theoretical capacity. A technology has been developed for using pyrite with an enrichment with FeS2 of at least 90 wt.%. As an electrolyte, eutectic mixtures “LiCl–KCl–LiF” were used. Gas-free pyrotechnic mixtures based on highly dispersed iron nanopowders with high specific heat release up to 1300 J/g and burning rates up to 100 mm/s have been developed. The pyrotechnic tape ignitors with a burning rate of 2.5 m/s are proposed, thus providing simultaneous ignition of the elements of the current sources and reducing the time of initiation and activation of the battery.

Nanomaterials in Thermal Backup Current Sources

The current-voltage characteristics of thermal batteries with anodes based on lithium and its alloys, with cathodes made of iron or cobalt disulfides are presented. The electrolyte-melt is a thickened mixture of fluorides, lithium and potassium chlorides, pyrotechnic mixtures of iron, molybdenum, titanium nanopowders. It is shown that the use of a lithium-boron composite and a “thickened lithium” composite is promising as a material for anodes of high-energy thermal current sources, and for cathodes - a mixture based on synthetic iron disulfide.

THE RESEARCH OF IGNITION AND COMBUSTION OF ALUMINUM AND MAGNESIUM ALLOYS IN THE PRODUCTS OF DECOMPOSITION OF SOLID PYROTECHNICAL FUELS

The results of experimental research of processes of ignition and combustion of particles of aluminum and magnesium alloys in gaseous purges of high-temperature decomposition of solid pyrotechnic fuels leading to their fire explosive hazardous development are presented. The relevance of these research is due to the wide scope of application of pyrotechnic products based on pyrotechnic mixtures of powders of aluminum-magnesium alloys with additives of organic substances, in particular applications in military technology and use in various industries related to the rotation of solid pyrotechnic equipment. Accordingly, in case of fire at facilities where pyrotechnic products are kept or during their transportation there exists the risk of ignition of pyrotechnic mixtures with different acceleration of their subsequent combustion process and destruction of the pyrotechnic products. As a result, high-temperature combustion products are formed, which are fire hazardous to the surrounding environment. Based on the foregoing, it is necessary to obtain data on the regularities of ignition and combustion particles of aluminum-magnesium alloys, which determines the ability to predict the properties of fire hazard pyrotechnic mixtures. As a result of conducted research, data on the ignition and combustion of particles of aluminum-magnesium alloys was obtained, in particular, the dependence of the delay time of the particles of aluminum-magnesium alloys on their chemical composition was obtained, the data on the process of combustion of particles of aluminum-magnesium alloys was obtained, the data on the effect of additives to aluminum-magnesium alloys was obtained.

Analysis of environmental impacts of combustion products of some pyrotechnic compositions

The study examined mixtures obtained from ready pyrotechnic articles available on the market in Poland. Samples were taken from various products with different performance characteristics, i.e. pyrotechnic batteries, firecrackers, volcanoes, as well as smoke candles, rockets (including rocket engines), and cold fires. These are the product categories most frequently used by users. The research allowed to determine gaseous combustion products and showed their life cycle in the environment. A comparative analysis of selected pyrotechnic mixtures was carried out in terms of their impact on the climate change of gas products. Using the ICT-Thermodynamic Code program, gaseous combustion products were estimated and the life cycle was analysed using the SimaPro program. Determining the impact on the environment (upon the basis of Ecoindicator 99) allowed to know the scale of the problem and set the direction of development of the pyrotechnic industry, so that importers could compete not only with the price and quality of products offered, but also tried to reduce the potential impact on the environment.

Use of Pyrotechnic Mixtures for Mining of Block Deposits

The article presents the results of estimates of thermodynamic parameters (oxygen balance, pressure, temperature, gaseous products produced in the reaction, specific energy, and the combustion heat) for 11 pyrotechnic mixtures and the final product—gas generator prototype (RSP), which can be used in mines for producing blocks. In addition, formal and legal considerations have been presented, as well as the results of gas generators in Polish mines. In order to compare the effects induced by using a detonating cord and a gas generator prototype, a test was carried out in granite quarries involving the measurement, at the same points, of vibration and the air blast. As a result of the tests, limitations and possibilities of using gas generators were indicated.

Determination of environmental burden of combustion products of pyrotechnic mixtures to quarrying operations

Using the ICT-Thermodynamic Code program, thermodynamic parameters and combustion products composition of the Rocksplitter type, containing different masses of pytotechnic mixture and black powder, were evaluated. The eco-indicator was determined on the basis of numerical falsification results obtained using the SimaPro PhD version 7.2 of the Dutch company PreConsultants. The environmental impact analysis was performed at the combustion temperatures of the tested mixtures and at 298 K.