Статті КГВФ ФБАІ ДІІТ

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Construction of a Mathematical Model of the Heat and Mass Transfer Process in the Main Fairing of a Launch Vehicle at the Pre-Launch Preparation Stage
(TECHNOLOGY CENTER PC, Kharkiv, 2025) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Rusakova, Tetiana I.; Kozachyna, Vitalii A.; Semenenko, Pavlo V.; Berlov, Oleksandr V.; Kirichenko, Pavlo S.; Hrudkina, Nataliia S.; Voitenko, Yuliia V.; Dolzhenkova, Olena V.
ENG: This study investigates the sequential and continuous formation of thermal fields in the main fairing of a launch vehicle when using protective screens. While thermostating, it is necessary to predict the risk in overheating the payload body and, if necessary, take measures to reduce the temperature near the payload. An engineering solution to this problem can be found through the use of protective screens of various configurations inside the main fairing. These screens reduce the heat flow from the heated outer wall of the fairing to the payload surface. However, there are no standard methods for solving this problem. To evaluate the effectiveness of this protection, a numerical model based on the fundamental equations of continuum mechanics has been constructed. The modeling equations include the energy equation and the equation of motion of a non-viscous gas. Using the numerical model built, a computational experiment was conducted, which confirmed the effectiveness of using protective screens to shield the payload body from excessive heating. The computer time required to perform the computational experiment is 3 seconds. This makes it possible to perform a significant number of calculations in a working day. The proposed simple technical means for protecting the payload from excessive heating could be used in the design of new models for rocket technology. Applying these screens slightly reduces the need for large volumes of clean air. The numerical model built could be used at specialized organizations at the “for-sketch” design stage. Numerical experiments have shown that the use of protective screens inside the main fairing makes it possible to achieve a temperature 2–4°C lower than the maximum permissible temperature near the payload.
Forecasting Zones of Air Pollution from Solid Waste Landfills
(Український державний університет науки і технологій, Дніпро, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kirichenko, Pavlo S.
ENG: Purpose. The work is aimed at developing a mathematical model that allows to quickly calculate the area of chemical air pollution during the emission of hazardous substances from solid waste landfills. The mathematical model takes into account meteorological parameters, geometric shape of the landfill, intensity of emission of hazardous substances from the landfill. Methodology. The two-dimensional equation of convective diffusion transfer of a conservative impurity from the atmosphere is used to analyze the intensity and size of chemical air pollution during the emission of hazardous substances from the landfill. A difference scheme of splitting is used to numerically solve the equation of convective-diffusive transfer of an impurity. The emission of hazardous substances from the landfill is modeled using the Dirac delta function. Findings. The developed mathematical model takes into account the main physical factors that affect the process of dispersion of hazardous substances from the landfill. On the basis of the developed numerical model, a computational experiment was conducted to assess the impact of the landfill on the environment. Originality. On the basis of the developed numerical model, a computer code was developed that allows predicting chemical pollution of the atmospheric wind and the underlying surface in the event of emission of hazardous substances from the surface of a solid waste landfill. The developed model and computer code make it possible to quickly assess the extent and intensity of environmental pollution from landfills, which is important when selecting sites for new or reconstructed landfills. Practical value. The software implementation of the developed numerical model was carried out, and a computational experiment was conducted to illustrate the effectiveness of using the model to solve applied problems related to the impact of landfills on the environment. The results of the numerical experiment are presented.
Mathematical Modeling of Heat and Mass Transfer Processes in Safety Labour Problems : Dust and Heat Pollution
(Prydniprovs’ka State Academy of Civil Engineering and Architecture, USUST, Dnipro, 2025) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Kirichenko, Pavlo S.; Kozachyna, Vitalii A.; Tymoshenko, L. O.
ENG: Problem statement. The operation of many industries is associated with dust and thermal air pollution. Particularly intense dust pollution of the air occurs during the operation of the mining complex. Intense thermal air pollution occurs during fires. Fires are a dangerous phenomenon at industrial and civil facilities. If a fire occurs at an industrial facility where oil storage facilities are located, a very intensive area of thermal pollution of the atmospheric air arises. This creates a risk of thermal injury to workers and a risk of ignition of oil storage facilities located near the source of ignition. An important practical task arises − reducing the risk of ignition of neighboring storage facilities. One of the means of reducing the risk of ignition is the use of protective screens, gabions at industrial sites. For practice, it is important to determine in advance the stability of such structures under the influence of a heat wave and to assess the "contribution" of these structures to reducing the air temperature near neighboring oil storage facilities. Reducing the air temperature near neighboring storage facilities increases the stability of bulk structures. Solving this class of problems requires the use of specialized mathematical models of aerodynamics and heat transfer. The purpose of the article. Creation of a CFD model for assessing thermal fields at an industrial site in the event of a fire and development of numerical models for predicting dust pollution of the air environment. Methodology. To simulate thermal fields at an industrial site, a potential flow and heat transfer model is used. To simulate the heating of a protective structure (shield), a one-dimensional heat conduction equation is used. Numerical integration of the modeling equations is carried out using explicit schemes. A mass transfer equation is used to model dust air pollution. Scientific novelty. Two numerical models are proposed for a comprehensive solution to the problem of determining the temperature field at an industrial site and inside a protective structure (screen) used to reduce the thermal load on a neighboring oil storage facility. Proposed numerical models for the analysis of dust air pollution. Practical significance. The implementation of the developed numerical models is implemented in real time. With the practical implementation of numerical models, almost all information regarding thermal fields formed on an industrial site during a fire can be obtained. This information allows you to identify areas with an intense increase in temperature, i.e. areas with a significant risk of injury to workers. Conclusions. Effective numerical models are proposed for solving complex problems in the event of a fire at an industrial site and in case of dust emission. The models make it possible to assess the level of thermal pollution of atmospheric air at the site and the effectiveness of using a protective screen to reduce the air temperature near a neighboring storage facility.
Numerical Modeling of Groundwater Dynamics and Heat and Mass Transfer Processes
(Pridneprovs’ka State Akademy of Civil Engineering and Architecture, USUST, Dnipro, Ukraine, 2024) Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kirichenko, Pavlo S.; Kozachyna, Valeriia V.; Kaidash, M. D.
ENG: Problem statement. Groundwater is undergoing significant anthropogenic impact in many countries around the world. This impact results in changes in groundwater levels and deterioration of their quality. Protecting groundwater from anthropogenic impact involves solving several important tasks. A significant number of tasks are related to the need to predict the processes of filtration and heat and mass transfer in underground flows. In this regard, it is important to have specialized mathematical models as a modern scientific research tool. It should be noted that the use of physical experiments for problems of this class is significantly limited, due to the high cost of equipment, considerable time spent on setting up and conducting the experiment. The purpose of the article. Development of a set of numerical models for simulation of filtration and heat and mass transfer processes in groundwater. Methodology. To model the process of non-pressure flow of groundwater, the equation of non-pressure filtration is used. The two-dimensional equation of convective-diffusive movement of a pollutant is used to model the process of mass transfer of an impurity in groundwater. To model the process of heat transfer in groundwater, in the problem of groundwater freezing, a two-dimensional energy equation is used. For numerical integration of modeling equations, finite-difference schemes are used. Scientific novelty. Numerical models of filtration and heat and mass transfer processes have been developed that allow real-time analysis of changes in groundwater quality and thermal regime. Practical significance. The developed numerical models make it possible to quickly analyze non-stationary processes of heat and mass transfer in groundwater when developing drainage systems in flooded areas. Conclusions. Numerical models of filtration and heat and mass transfer in groundwater have been developed. For the practical use of the built models, standard hydrological information is required. The models make it possible to analyze the dynamics of ice formation in groundwater during the implementation of the technology of freezing groundwater flow.