ННІ "Придніпровська державна академія будівництва та архітектури" (ННІ ПДАБА)

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ENG: SEI “The Prydniprovska State Academy of Civil Engineering and Architecture” (SEI PSACEA)

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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.
Modeling of Filtration and Geomigration Under Anthropogenic Impact on Groundwater
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Tiutkin, Oleksii L.; Mashykhina, Polina B.; Berlov, Oleksandr V.
ENG: Purpose. One of the most widespread methods of liquid waste disposal is the use of settling ponds. Wastewater in such lagoons eventually infiltrates into the aeration zone and reaches groundwater. Thus, a chemical contamination area is formed both in the aeration zone and in groundwater. When reengineering sedimentation ponds (for example, when increasing the height of the dam), there is an increase in the pressure in the structure, which will affect the intensity of infiltration of wastewater from the pond into the aeration zone), it is necessary to determine the change in the intensity of environmental pollution in advance. To solve such a forecasting problem, it is necessary to use specialized mathematical models. The aim of the study is to develop numerical models for assessing the dynamics of aeration zone pollution during the infiltration of liquid waste from a sedimentation pond. Methodology. The Laplace equation for the head is used to solve the filtration problem. The process of mass transfer of impurities in the aeration zone is modeled using the mass transfer equation, which takes into account the convective-dispersive transfer of impurities. The numerical integration of the modeling equations is carried out using finite-difference schemes. Findings. Numerical models of filtration and mass transfer are considered, which allow to estimate the dynamics of changes in the contamination area in the aeration zone during the infiltration of liquid wastewater from a sedimentation pond. Originality. The construction of mathematical models for analyzing the infiltration of liquid wastewater from a sedimentation pond is considered. Numerical models take into account the convective-dispersion process of impurity propagation in the aeration area. Practical value. The considered numerical models can be used to assess the environmental impact of sedimentation ponds used for the accumulation of liquid waste.