Journal of Civil Protection

Mathematical model for predicting fire-extinguishing foam expansion rate in deflector type sprinklers

2026-06-05T18:33:17+03:00

Purpose. Based on the results of experimental studies, develop a mathematical model for predicting the foam multiplicity, taking into account the main parameters of the foam formation process in deflector type sprinklers for automatic fire extinguishing systems.

Methods. The general methodology of the work included the theoretical (analysis, synthesis, comparison) and experimental research methods. The foam expansion rate was determined experimentally using the developed method. Statistical analysis of experimental data and formulation of the mathematical model included regression and correlation analyses, as well as analysis of residuals, including the normality of their distribution using the Pearson criterion.

Findings. Based on experimental data, the mathematical model has been developed for predicting fire-extinguishing foam expansion rate based on sprinkler geometry, hydrodynamic conditions, and the physical and mechanical properties of the foaming solution. The model's structure includes dimensionless complexes reflecting the influence of the effective surface area coefficient of the deflector K_s, the relative length of the frame arms L_f / D, the relative diameter of the deflector D / D_max, and the capillarity number Ca, providing a comprehensive account of the sprinkler geometry and foaming process parameters. The average deviation of the calculated foam expansion rate values from the experimental data does not exceed 11 %, and the maximum deviation is 27 %. An analysis of the residuals revealed no systematic relationship between the residuals and the predicted values and confirmed the normality of the residual distribution. Furthermore, the relationships identified during the experiment indicate the complex influence of the sprinkler's geometric parameters on foam expansion rate, particularly relative length of the frame arms L_f / D. The most significant increase in foam expansion rate is achieved by increasing the capillarity number and the working surface coefficient of the deflector, while the influence of the relative diameter of the deflector is less pronounced.

Application field of research. Design and operation of deflector sprinklers for automatic fire extinguishing systems. The proposed model allows for the selection of the required foam generation configuration, taking into account the foam concentrate used, the foam solution delivery conditions, and the sprinkler's key geometric parameters to produce foam with a specified expansion rate.

Field tests of fire extinguishing compositions delivered for extinguishing by fine spraying

2026-06-05T18:33:26+03:00

Purpose. To develop an experimental methodology and study the effect of the operating pressure before a finely atomized water spray nozzle on the droplet size in the spray cone using the previously developed film-forming fire extinguishing agent V3. To conduct field tests to determine the extinguishing time of a model fire of a water-insoluble flammable liquid using the developed film-forming fire extinguishing agent and commercially available analogs.

Methods. Droplet size in the flow was measured instrumentally using a Winner 319 industrial aerosol particle size analyzer, which operates using laser diffraction. Extinguishing times for fire extinguishing agents were determined experimentally, and the experimental data were processed using the uncertainty estimation and expression method.

Findings. A method for measuring the droplet size of water-based fire extinguishing agents applied by spraying has been developed. Droplet sizes of the previously developed film-forming fire extinguishing agent V3 (with a component ratio optimized for extinguishing time) were measured when applied through a Briz9/K16 fine-mist sprinkler. It was found that to form a spray cone with droplet diameters smaller than 150 µm using the specified Briz9/K16 sprinkler, the V3 film-forming fire extinguishing agent must be supplied under an operating pressure of 0.6 to 1.0 MPa. Field tests were conducted on extinguishing a model Subclass B1 fire using four fire extinguishing agents: the V3 fire extinguishing composition, PO-6RTS (Russia), PO-6RTF (Russia), and the film-forming barrier 3 NS (Belarus). The use of the developed V3 fire extinguishing composition was found to reduce the extinguishing time of a model Subclass B1 fire by at least 38 % compared to similar products.

Application field of research. The developed methodology for studying the physical parameters of dispersed droplets from a deflector sprinkler of finely atomized water can be applied in the development of domestic regulatory legal acts for studying the parameters of the spray torch of deflector sprinklers used in automatic fire extinguishing systems.

Electrocrystallization regularities of hard Ni-Co and Ni-Co-P alloys for strengthening of parts of emergency rescue equipment

2026-06-05T18:33:27+03:00

Purpose. To study the patterns and determine the optimal conditions for hydrometallurgical synthesis of protective and strengthening coatings from Ni-Co and Ni-Co-P alloys for modification surface of emergency rescue equipment parts.

Methods. Gravimetry, voltammetry, X-ray spectral analysis.

Findings. It was determined that within the permissible range of current densities (1–6 A/dm²) and a fairly wide temperature range (up to 40 °C), the deposition of Ni-Co alloys proceeds without thickness limitations, indicating the absence of cathodic passivation. For Ni-Co-P, the optimal method for obtaining dense, defect-free protective films is alloy deposition at room temperature in the current density range of 3–7 A/dm² at a rate of 30–60 μm/h. The nickel content in coatings can vary between 35 and 75 at. %; the cathode current density has the predominant influence on the nickel content in the alloy. The formation of the Ni-Co alloy occurs without some depolarization of cobalt, in the absence of limiting diffusion currents and cathode passivation. For the Ni-Co-P alloy, significant depolarization of both cobalt and nickel is observed due to their additional reduction by hypophosphite, which significantly increases the rate of coating formation compared to Ni-Co.

Application field of research. Protection against wear and corrosion, increased resistance to impact and thermal loads, friction, and deformation of parts made of low-carbon steels.

On bubble generation regimes in a surfactant solution for producing compression foam

2026-06-05T18:33:28+03:00

Purpose. To investigate the regimes of bubble generation in a surfactant solution for producing compression foam and their geometric characteristics at a submerged orifice. Based on the obtained experimental data, to identify and describe the principal regimes of bubble generation in a surfactant solution for producing compression foam. To determine the characteristic Reynolds, Weber, Froude, Mach, capillarity, Bond and Morton numbers that can be used to assess the bubble generation regimes in a surfactant solution for producing compression foam and their geometric characteristics at a submerged orifice.

Methods. The general methodology of the work involved the use of theoretical (analysis, synthesis, comparison) and experimental research methods. The methods of visualization and photography, digital image processing, and a computational method were applied.

Findings. Three successively alternating modes of bubble generation in a surfactant solution at a submerged orifice were experimentally established: bubble, garland (transitional), and jet. The criteria for these modes were determined: for bubble: Reynolds number – Re < 1000, Weber – We ≤ 15, capillarity – Ca_max = 0.018, Mach – M_max = 0.075, and the average gas content – φ_av^min = 0.769, φ_av^max = 0.997; for garland: 1000 ≤ Re ≤ 2000, 3 ≤ We ≤ 45, Ca_max = 0.031, M_max = 0.129, φ_av^min = 0.954, φ_av^max = 0.998; for jet: Re > 2000, We ≥ 80, Ca_min = 0.029, M_min = 0.123, φ_av^min = 0.998. It is shown that even at low air velocities, deformed (elliptical) bubbles are generated in a solution with surfactants as confirmed by the Bond number values Bo > 1 and Geometric characteristics are defined for each mode: for the bubble mode, the equivalent bubble diameter and the interbubble pitch; for the garland mode, the distance between the garland and the bubbles and the garland height; and for the jet mode, the torch height and its opening angle. The jet mode is considered the most effective in terms of gas saturation and bubble dispersion.

Application field of research. Research of the modes of bubble generation in a surfactant solution for obtaining compression foam and their geometric characteristics at a submerged orifice can be used to optimize barbotage processes for fire extinguishing, flotation, food production, and the production of porous materials.

Using SLAM systems in unmanned aircraft complexes to assess situation in emergencies

2026-06-05T18:33:29+03:00

Purpose. To conceptually substantiate and analyze the application of SLAM systems in unmanned aerial vehicles for precise 3D and 4D mapping of objects and terrain in emergency situations to provide timely and accurate information to emergency response managers (ERM).

Methods. A review of existing SLAM architectures, analysis of multi-sensor data fusion methods, comparison of algorithms (LOAM, LeGO-LOAM, LIO-SAM, etc.) based on literature sources and a conceptual evaluation of the results using metrics of mapping accuracy, model resolution, and sustainability to interference.

Findings. Multisensor SLAM systems demonstrating the potential for creating highly accurate 3D models of objects and terrain in extreme conditions were analyzed. It has been established that the use of SLAM for operational mapping in emergency situations allows for increasing the accuracy of information for ERM, reducing the time for making management decisions and minimizing risks during emergency response.

Application field of research. The conceptual conclusions obtained can be used to develop strategies for implementing SLAM systems in unmanned aerial vehicles for monitoring and modeling emergency zones, emergency response radar information systems, and for solving other life safety problems.

Assessment of strength and stability of external information and advertising structures based on modeling in ANSYS environment

2026-06-05T18:33:30+03:00

Purpose. The purpose of this study is to increase the strength, stability and safe operation of outdoor advertising structures (billboards) based on the modern ANSYS engineering modeling software package.

Methods. To create a digital model of the design, an integrated approach was applied, combining the stages of geometric construction and engineering calculation. The original geometry was created in Autodesk Inventor Professional CAD system. ANSYS module was used for strength and dynamic calculations.

Findings. Complex modeling in the ANSYS environment made it possible to obtain results characterizing the behavior of the billboard design under design loads. It was found that at an incoming flow speed of 23 m/s, the average integral aerodynamic pressure on the plane of a standard size board of 3x6 m is 340 Pa. Visualization of the pressure and velocity fields confirmed the formation of a classic picture of the flow around a flat obstacle, a high pressure zone on the windward side and a turbulent rarefaction zone with vortex formation on the leeward side and on the sides of the structure. The resulting wind load is determined, which for this area is 6.1 kN.

Application field of research. The model is the basis for the development of reasonable smooth repair and maintenance, predicting the residual life of structures. On the basis of modeling, it is possible to develop a program for point instrumental control of specific critical nodes.

Scientific justification of nutritional development as an element of the protection system in emergency situations

2026-06-05T18:33:31+03:00

Purpose. To develop a scientifically based, specialized food product with a nutritional focus and experimentally confirm its effectiveness as an element of a protection system in emergency situations.

Methods. Analytical – comparative analysis of diets approved by regulatory legal acts in several regions of the Russian Federation, the CIS member states, and the Baltic states. Technological – development of a nutritional support composition with increased nutritional value, adhering to ingredient functionality criteria, including sorption capacity, antioxidant activity, and essential mineral content. Experimental – product safety assessment using biotesting and determination of antioxidant activity using the ferricyanide method, with data processing using statistical analysis methods and the Statistica 10.0 software package.

Findings. The article presents the results of a comparative analysis of 35 approved diets, which revealed a deficiency of essential nutrients critical for protection in emergency situations: dietary fiber (53.0 % deficiency), dried fruits (69.2–78 %), vitamin C (57 %), vitamin E (67 %), omega-3 polyunsaturated fatty acids (72 %), potassium and magnesium (33 % each). A nutritional support product has been developed that compensates for the identified deficiency of dietary fiber (8.5 g/100 g, 34 % of the daily value), magnesium (131 mg/100 g, 33%), vitamin A (279.8 μg/100 g, 31 %), and potassium (346 mg/100 g, 14 %). Biotesting confirmed the product's safety (Paramecium caudatum survival rate was 97.2±1.3 % versus 98.5±1.1 % in the control, p > 0.05). The extract's antioxidant activity was 74.5±0.3 % and was maintained for 60 days of storage (a decrease of no more than 1.5 %, p > 0.05).

Application field of research. The study results can be recommended for inclusion in individual diets for fire and rescue personnel involved in emergency response, as an element of protection against intoxication, oxidative stress, and electrolyte imbalance.

Ensuring radiation safety in border service agencies by optimizing radiation doses

2026-06-05T18:33:32+03:00

Purpose. To justify the limits of acceptable hazardous doses in addition to natural background radiation for border service personnel guarding the state border under various radiation conditions.

Methods. Analysis and description of the specific effects of various types of radiation and the characteristics of certain radionuclides. Comparative analysis and generalisation of information on the radiation dose burden on border service personnel.

Findings. The key factors recommended for consideration in the process of standardizing radiation dose loads and determining the consequences of radiation exposure were identified. Predicted exposure dose rates were calculated for the purpose of distributing the dose load among personnel performing state border protection tasks in conditions of radioactive contamination. Data from an automated dosimetric monitoring system for military personnel performing border protection tasks in the Polesie State Radiation Ecological Reserve was analyzed. Basic radiation dose limits for border service personnel operating in radiological emergencies were proposed.

On the issue of environmental safety at electrical substations with a voltage of 110 kV and above

2026-06-05T18:33:33+03:00

Purpose. Analysis of information indicating the need to develop a program aimed at improving the system of industrial environmental control and the application of preventive measures to reduce the negative impact of electromagnetic field intensity levels near high-voltage equipment on the territory of electrical substations with a voltage of 110 kV and higher.

Methods. Experimental investigation of the spatial distribution of the electromagnetic field with the formation of intensity maps for industrial frequency (50 Hz) and high-frequency fields.

Findings. It is shown that the electromagnetic environment at such facilities is characterized by high values of electric and magnetic field strengths in a wide frequency range. Information is provided on the sources of electromagnetic fields at electrical substations, as well as maps of the distribution of field levels both at low frequency and in the high frequency range. Information on the spectral composition of the electromagnetic radiation emitted by 500 kV power autotransformers is presented. It is noted that the most powerful radiation is observed in the range from 1 to 150 MHz. The distribution maps of increased field strength levels at substations for various frequencies are given as examples. The most dangerous areas for maintenance personnel and the factors influencing the increase in field intensity have been identified. The results of experimental studies are presented, showing that for equipment with a service life exceeding the standard, there is an increase in the levels of electromagnetic fields. It is concluded that in order to protect personnel at electric power facilities, it is necessary to develop measures to protect against electromagnetic interference, depending on the location of high-voltage equipment at the power facility.

Application field of research. These studies are focused at researching the problem of improving environmental control to prevent excessive exposure to the human body. The obtained results can be used to develop and improve the methods of environmental control at high-voltage substations of 110 kV and higher.

Theoretical and methodological foundations of complex protection of organizations subject to shift working under wartime conditions

2026-06-05T18:33:34+03:00

Purpose. Improvement of the scientific and methodological framework for supporting the adoption of technical solutions in the field of civil defense, which are aimed at increasing the stability of organizations' functioning during military operations or in the result of such operations, as well as at emergencies.

Methods. The article used general scientific research methods: induction and deduction, analysis and synthesis, comparison and generalization, analogy, elements of legal and system analysis, as well as the method of hierarchical analysis, were applied.

Findings. The presented article accumulates and systematizes the most significant results obtained by the author of this article at the previous stages of scientific work. An attempt is made to form a holistic view of the theoretical and methodological foundations of the integrated protection of organizations that are to be sgifted to work in wartime conditions. Applications field of research. The results of the study can be used in the development and revision of regulatory legal acts in the field of civil defense, applied by civil defense management bodies at various levels to assess the current level of integrated protection of organizations, form priorities in the areas of increasing the sustainability of the functioning of economic sectors, substantiate organizational and engineering and technical measures of civil defense, monitor their effectiveness and adjust them.

Status and prospects of scientific and technical support for operation of the Belarusian nuclear power plant

2026-06-05T18:33:34+03:00

Purpose. An analysis of the state of the system of technical (scientific and technical) support for the operating organization, a comparison and evaluation of the compatibility of such systems of the regulatory body and the operating organization, and the development of proposals to improve approaches to organizing and coordinating activities aimed at providing technical and scientific support to the Belarusian NPP.

Methods. A group of theoretical research methods aimed at understanding the essence of processes and phenomena: analysis, synthesis, comparison, generalization, concretization, analogy.

Findings. Legal norms at the international and national levels were analyzed with regard to providing scientific and technical support to organizations operating nuclear facilities and to nuclear and radiation safety regulatory bodies. Terminological features in the field of organizing and implementing scientific and technical support were identified. Various aspects of the functioning of scientific and technical support systems were examined. Organizational proposals were developed, based on national experience, aimed at improving approaches to organizing and providing scientific and technical support to the operating organization of a nuclear facility.

Application field of research. Improvement of the legal framework in the field of ensuring nuclear and radiation safety, as well as the organization and functioning of the system of scientific and technical support for the operating organization; creation of a set of measures to reduce the prerequisites for conflicts of interest among scientific and technical support organizations providing consultation to both operating organizations and the regulatory body.