CRUST | Browsing by Author "Mashykhina, Polina B."

Browsing by Author "Mashykhina, Polina B."

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3D Modeling of Biological Wastewater Treatment in Aeration Tank
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2020) Biliaiev, Mykola M.; Lemesh, Maksym V.; Gunko, Olena Y.; Zadoia, Viacheslav O.; Mashykhina, Polina B.; Yakubovska, Zinaida M.
ENG: Purpose. The main purpose of the article is to develop a 3D CFD model for modeling the process of biological wastewater treatment in an aeration tank. Methodology. For mathematical modeling of the process of biological wastewater treatment in the reactor, taking into account the flow hydrodynamics, geometric shape of the aeration tank, convective-diffusion transfer of the substrate and activated sludge, a 3D CFD model was built. The model is based on the three-dimensional equation of motion of an ideal liquid and the equation of mass conservation for the substrate, activated sludge. The field of sewage flow rate in the aeration tank is calculated based on the velocity potential equation. The process of biological transformation of the substrate is calculated on the basis of the Monod model. The splitting scheme was used for numerical integration of the equations of convective-diffusion transfer of activated sludge and substrate. The splitting is carried out in such a way to take into account the transfer of substrate (activated sludge) in only one direction at each step of splitting. The calculation of the unknown value of the substrate (activated sludge) concentration is carried out according to an explicit scheme. The Richardson method is used to numerically integrate the three-dimensional equation for the velocity potential, and the unknown value of the velocity potential is calculated by an explicit formula. Euler's method is used for numerical integration of equations describing the process of substrate transformation and change in activated sludge concentration (Monod model). Findings. The software implementation of the constructed 3D CFD model is carried out. A description of the structure of the developed software package is provided. The results of a computer experiment to study the process of wastewater treatment in an aeration tank with additional elements are presented. Originality. A new multifactor 3D CFD model has been developed, which allows quick assessing the efficiency of biological treatment in an aeration tank. Practical value. The constructed 3D CFD model can be used to analyze the efficiency of the aeration tank under different operating conditions at the stage of sketch design of wastewater treatment systems.
Analysis of Air Dust Pollution in the Transport Compartment of the Launch Vehicle at the Stage of the Pre-launch Preparation
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.; Mashykhina, Polina B.; Semenenko, Pavlo
ENG: At the stage of the pre-launch preparation, it is necessary to fulfill very strict environment conditions inside the main fairing where the satellite is located. Namely, it is very important to predict dust concentration inside the main fairing and especially near satellite surface during forced ventilation. To predict air dust pollution inside of main fairing 2D fluid dynamics numerical model has been developed. The governing equations include equation of potential flow to simulate air flow inside the main fairing and equation of pollutant dispersion. Also, empirical model has been used to calculate the number of dust particles fall to the satellite surface. Implicit finite difference schemes of splitting have been used for numerical integration of governing equations. The computer code has been developed on the basis of proposed numerical model. The results of computational experiments to estimate dust concentration field inside the main fairing of the launch vehicle are presented.
Computer Simulation of Biological Wastewater Treatment Processes in Aerotanks With Plates
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2020) Biliaiev, Mykola M.; Lemesh, Maksym V.; Biliaieva, Viktoriia V.; Mashykhina, Polina B.; Yakubovska, Zinaida M.
EN: Purpose. Efficiency determination of the aeration tank at the stage of design or reconstruction of bioreactors in which biological wastewater treatment is carried out requires the use of special mathematical models and calculation methods. The main purpose of the article is to develop CFD models for evaluating the operation efficiency of aeration tanks. Methodology. A numerical model has been developed for the computer calculation of the biological wastewater treatment process in aerotanks, taking into account hydrodynamics. The model is based on two-level mass conservation equations for the substrate and activated sludge and the velocity potential equation. The process of biological transformation of the substrate is calculated based on the Monod model. For the numerical integration of the mass transfer equations of activated sludge and substrate, the alternating-triangular difference splitting scheme is used. In this case, the basic equations are divided into two equations of a more simplified form. For the numerical integration of the equations for the velocity potential, it is split into two one-dimensional equations. Further, each equation is solved according to explicit scheme. For the numerical integration of equations that describe the process of substrate transformation based on the Monod model, the Euler method is used. Findings. The software implementation of the constructed numerical model has been carried out. The results of a computational experiment on the study of the wastewater treatment process in an aeration tank with plates are presented. This leads to the conclusion that the quality control of wastewater treatment in aeration tanks is possible with the help of plates. Originality. A multivariate CFD model has been developed, which makes it possible to quickly assess the efficiency of the aeration tank. A feature of the model is the ability to evaluate the operation of the aeration tank, taking into account its geometric shape and location of additional plates in the construction. Practical value. The constructed numerical model can be used during calculations in the case of designing aeration tanks, or in determining the efficiency of wastewater treatment under new operating conditions.
Computer Simulation of Dead-End Mine Working Ventilation
(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Biliaieva, Viktoriia V.; Kirichenko, Pavlo S.; Gunko, Olena Y.; Bondarenko, Iryna O.; Mashykhina, Polina B.; Yakubovska, Zinaida M.
ENG: Purpose. The important problem in the field of ecological safety and industrial safety is providing of normal microclimate in dead-end mine working. In these regions of the mine methane gas can be accumulated and as a result explosion may take place. So, to avoid these accidents it is important to ventilate appropriately dead-end mine working. The purpose of the work is development of quick computing mathematical model to obtain information about dead-end mine working ventilation process. Methodology. The process of dead-end mine working ventilation computing is separated in two stages. At the first stage the velocity flow field is computed in the dead-end mine working. We consider the situation when the suction tube is situated in this region. To solve this problem the fluid dynamics model of inviscid gas flow was used. At the second stage of the computational modeling the convective-diffusive equation of admixture transfer was used. The equation takes into account non-uniform flow field in the dead end mine workings. Findings. The developed numerical model was coded using FORTRAN language. The developed computer code allows to perform numerical experiment to assess the efficiency of suction tube imple-mentation to decrease methane gas concentration in dead-end mine working. Originality. The developed numerical model takes into account physical factors, which are not considered nowadays in the empirical models, which are used for solving the problems of dead-end mine working ventilation. It allows taking into account the geometrical form of the dead-end mine working. Practical value. The developed computer program allows to perform calculations to assess the efficiency of suction system used for the ventilation of the dead-end mine working.
Predicting Dust Pollution in the Passenger Compartment
(Kaunas University of Technology, Kaunas, 2022) Biliaiev, Mykola M.; Rusakova, Tetiana I.; Biliaieva, Viktoriia V.; Mashykhina, Polina B.; Rusakova, Kateryna
ENG: Fine dust particles, which are present in the air in large quantities, are dangerous to human health. They enter the body through the lungs, but move to almost all organs, causing a number of respiratory diseases, pneumonia and are carriers of the coronavirus. This research proposes a method for numerically calculating the process of dust pollution of the passenger compartment when fine dust enters the cabin through the ventilation system. To calculate the concentration field of dust in the cabin, the equation of convective-diffusion dust dispersion is used, which takes into account the intensity of dust entering the passenger compartment, the unevenness of the air flow velocity field in the passenger compartment, diffusion, and additional dust emission from the floor surface. To calculate the velocity field of the air flow in the car interior, a potential flow model is used, the modeling equation is the Laplace equation for the velocity potential. For the numerical integration of the convective-diffusion dispersion equation of fine dust in the cabin, implicit finite-difference splitting schemes are used. For the numerical solution of the equation for the aerodynamic velocity potential, the alternating-triangular method of A. Samarsky is used. The computer code has been developed that implements the method of numerical calculation. The results of computational experiments to assess the level of dust pollution in the passenger compartment are presented.
Quick computing CFD model to predict chemical pollution in room
(Український державний університет науки і технологій, Дніпро, 2025) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Mashykhina, Polina B.
ENG: Purpose. The problem of accidental contamination of workspaces attracts special attention, since in the event of such extreme situations, intense chemical contamination of the air in work areas occurs. This poses a threat of toxic exposure to workers. When assessing the consequences of such situations, it is necessary to take into account the time factor, in particular, to quickly determine the creation of concentrations of chemically hazardous substances. In this regard, an urgent task is to develop effective mathematical models for rapid assessment of the consequences of extreme situations in the working areas of chemically hazardous facilities. The paper considers a CFD model for analyzing the process of chemical air pollution in a workspace during an accidental release of a chemically hazardous substance. The solution of the problem is based on the numerical integration of the fundamental equations of continuum mechanics. Methodology. To calculate the air velocity field in the working room during the operation of supply and exhaust ventilation, a mathematical model of the motion of an inviscid fluid was used. The equation of convective diffusion motion was used to calculate the concentration of a chemically hazardous substance in the workspace. The integration of the modeling equations was carried out using finite difference schemes. Findings. A dynamic model has been created to calculate the spread of a chemically hazardous substance in a work-space. On the basis of the built CFD model, a computer program was created to conduct a computational experiment. Originality. A CFD model has been created to predict the level of air pollution in a workspace in the event of toxic gas emissions. The model is based on the fundamental equations of aerodynamic mechanics and mass transfer. The model makes it possible to determine the effect of the ventilation mode, the intensity of emission of a chemically hazardous substance, the location of equipment in the workspace, and the dynamics of the formation of concentration fields. Practical value. The developed CFD model can be used to quickly analyze the consequences of accidental emissions of a chemically hazardous substance in a workplace and assess the risk of toxic exposure of workers.
Reducing Ammonia Concentrations in Atmosphere After its Unplanned Release
(Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Dnipro, 2017) Amelina, Larysa V.; Biliaiev, Mykola M.; Mashykhina, Polina B.
EN: Purpose. The aim of this work is development of numerical model, which allows to calculate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia emission at the territory of ammonia pump station. The numerical model should allow fast calculating, taking into account the meteorological parameters and buildings situated near the source of toxic chemical emission and equipment for neutralizer supply. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. To simulate the chemical interaction between ammonia and neutralizer the stoichiometry equation is used. Equation of potential flow is used to compute flow pattern among buildings. To solve the equation for potential flow the Samarskii implicit difference scheme is used. The implicit change-triangle difference scheme is used to solve equation of mass transfer. While for the numerical integration the authors use the rectangular difference grid. Method of porosity technique («markers method») is applied to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of ammonia and neutralizer in the atmosphere, as well as the influence of buildings on admixture dispersion. On the basis of the developed numerical models the authors carried out a computational experiment to estimate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows calculating the flow pattern among buildings and estimating the efficiency of neutralizer supply for reduction of air pollution in the case unplanned ammonia release. Practical value. Model allows performing fast calculations of the atmosphere pollution in the case of unplanned ammonia release.
Risk Assessment in Case of Toxic Chemical Emission at Railway Transport
(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Biliaieva, Viktoriia V.; Mashykhina, Polina B.; Kalashnikov, Ivan V.; Berlov, Oleksandr V.; Kravets, Ivan B.
EN: Abstract. Risk assessment during emission of toxic chemicals at railway transport is the problem of great scientific interest. To make such assessment we need special computer models. At present, in Ukraine,we have lack of such models. The authors present numerical models for territorial risk assessment in case of organized emissionsat railway transport (for example, emissions during locomotive movement) and in case of accident emissions (accident spills of dangerous cargo, emissions of NH3 from railway tank, etc.).The basis of the developed numerical models is the system of fundamental equations of fluid dynamics.These equations are solved numerically using implicit schemes of splitting. The developed models allow to take into account some important factors which influence the territorial risk value: probability of atmosphere conditions, train route, transport infrastructure at railway stations, probability of emission site.Also the process of pollutant chemical transformation in the atmosphere is taken into account in the developed models. The developed models allow to predict territorial risk in case of moving source of emission (moving damaged railway tank).The results of numerical experiments are presented. These results illustrate territorial risk maps for different sites near Prydniprovska railway.
Simulation of Chemical Accident with Ammonia at the Pipe Line
(Kaunas University of Technology, 2023) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia; Mashykhina, Polina B.
ENG: Ammonia is transported through Ukraine via the Togliatti-Odesa ammonia pipeline. The hostilities in Ukraine pose a risk of damage to this transportation system as a result of a shell, mine, etc. hitting the transportation system. Therefore, it is very important to predict the possible consequences of environmental pollution in the event of such an extreme situation. A numerical model was developed to solve this problem. The three-dimensional equation of convective-diffusive transport of an impurity in the atmosphere is used to predict the dynamics of pollution of atmospheric air and the underlying surface. Finite-difference splitting schemes are used to numerically integrate this equation. On the basis of the constructed numerical model, a computer code was developed to take into account the change in the intensity of ammonia leakage from the damaged pipeline. The results of a computational experiment are presented.
Simulation of Ground Waters Pollution Near Pools with Mine Wastewaters
(Національний гірничий університет, Дніпро, 2018) Biliaieva, Viktoriia V.; Mashykhina, Polina B.; Yakubovska, Zinaida M.
EN: The results of the study, dedicated to the process of ground waters pollution near pools. The purpose of the study is development of numerical model to compute quickly ground waters pollution near pools with mine waste waters. The method of the research is CFD simulation. Findings. New numerical model is proposed to compute the process ground waters pollution near pools. The originality. New model was developed for 2D computing of ground waters pollution. Practical implications. Developed model allows quick computing of ground waters pollution near pools with waste waters.
Technology for Water Purification From Residues of Drugs and Plastic
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Dolina, Leonid F.; Mashykhina, Polina B.; Dolina, D. A.
EN: Purpose. The main purpose of the article is to develop a technology for water purification from residues of oilfat-cream containing drugs, in particular technology and a technological scheme for purifying urban (municipal) wastewater from plastics and residues of drugs. Methodology. The studies were carried out based on the analysis of scientific sources and reporting data on the availability of drugs and plastics in the water of Ukraine, European countries, and the USA. Findings. The authors present the results of a comprehensive review of issues related to the determination of the availability of drugs in various waters, their concentrations and the most dangerous drugs-toxicants. Medicines and plastics can accumulate not only in humans and animals, but also in sea and river fish, etc. The presence of drugs and plastic in the body can have a negative impact on the health. The treatment facilities in Ukraine and the world are not sufficiently adapted for the detection of drugs and plastics and their purification. Originality. The authors of this material conducted studies to determine the content of plastic in drinking tap water in Dnipro and Zaporizhzhia cities. Drinking water from the tap contains less plastic particles than bottled water of the famous Ukrainian trade brands. The work developed technological schemes for the purification of industrial wastewater from pharmaceutical enterprises for the manufacture of creams, ointments, oils and other products for treatment and cosmetic purposes. Structures and methods for purifying water from these pollutants have been pro-posed, which had not been previously used at water purification stations, but successfully apply in other industries. Practical value. The use of environmentally efficient technologies in Ukraine will allow obtaining high-quality drinking water, but it will require re-equipment and reconstruction of water treatment plants. Major funding should be provided by corresponding articles. Currently, in Ukraine (even in Kyiv) there are no stations for the purification of drinking and waste waters, which would use modern technologies and facilities, but high-quality water is the health and life of people.
Water Reality in Ukraine and Worldwide
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Dolina, Leonid F.; Mashykhina, Polina B.; Karpo, Alina A.; Mishchenko, Andrey A.
EN: Purpose. The paper analyzes the state of water management in Ukraine and worldwide, as well as the best practices in this area. Methodology. The study was carried out based on the analysis of literature sources and reporting data on the state of water management in Ukraine, European countries, the USA (2010-2016). Findings. The water state analysis in the regions of Ukraine showed that the quality in most cases is close to or meets the requirements for drinking water. Drinking tap water requires post-treatment in all regions of the country. The main issue for today is the production of the necessary equipment for treatment plants. Unfortunately, not all equipment is produced in Ukraine. The condition of rural water pipelines is of particular concern. Among the tested pipelines 7.3% do not comply with the rules and regulations. At the same time, only 25% of villages in Ukraine are provided with centralized water supply. Originality.The authors presented the results of a comprehensive review of the world's issues on disinfection of drinking and waste water, where various methods are used, partly in combination with each other in Ukraine and the worldwide. The main unresolved issue today is the issue of the residual quantity of drugs in the drinking water. The main environmental threat of the world scale is the presence of medicines in drinking water. The treatment facilities are not suitable for the decomposition or trapping of medicinal products. Nowhere in the world there is protection from these substances. One of the key issues in the solution of drinking water production is seawater desalination. To reduce the cost of desalination of sea water the SWRO-membrane technology is used. Practical value. Water problems are number one problems all over the world and in Ukraine as well. It is necessary to provide for additional financing to solve problems in the preparation and purification of waters, not with whatever funds remain, taking into account the fact that water is the basis of life on earth as a whole, the health and life of the nation depends on the quality of the water supply source.
Watering of Cargo for Reducing Dust Emissions from Coal Wagon
(Kaunas University of Technology, Kaunas, Lithuania, 2021) Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Mashykhina, Polina B.; Tyshchenko, Serhii S.
ENG: Open topped coal wagons are widely used in different countries. The coal surface exposed to air emits intensively fugitive dust. Water application is used for reducing fugitive dust emissions from open topped coal trains. The objective of this research was to develop numerical model to study efficacy of water application on the surface of coal. To simulate air flow over coal wagon Euler equations were used. These equations were written in Helmholtz variables “vorticity–flow function”. Finite difference schemes of splitting were used for numerical integration of Euler equations. To simulate coal dust dispersion from coal wagon mass transfer equation was used. This equation took into account air flow speed, turbulent diffusion, dust emission rate from cargo surface. To solve mass transfer equation change-triangle implicit difference scheme of splitting was used. To simulate water evaporation from cargo and dust emission rate dependence from moisture, empirical models were used. On the basis of developed numerical model computer code was developed using FORTRAN. Results of numerical experiments are presented.

Browsing by Author "Mashykhina, Polina B."

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