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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.
Calculation of «Vulnerability» Zone in Case of Terrorist Attack with Chemical Agents
(Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2018) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Kalashnikov, Ivan V.; Kozachyna, Vitalii A.
EN: Purpose. The work involves the development of a numerical model for calculating the «vulnerability» zone of a possible terrorist attack objective with the use of a chemical agent in a builtup environment. The «vulnerability» zone is a territory near the attack objective, where the emission of a chemical agent during the attack will lead to undesirable consequences. The emission of a chemical agent outside the «vulnerability» zone will not create a dangerous concentration near the attack objective. Methodology. To solve this problem, we use the equation for the velocity potential, on the basis of which we determine the wind stream velocity field, and the equation adjoint to the equation of mass transfer in the atmospheric air of the chemical agent emitted in the event of a terrorist attack. During simulation, we take into account the uneven wind stream velocity field, atmospheric diffusion and the rate of emission of a chemically hazardous substance. For the numerical integration of the velocity potential equation, we use the method of A. A. Samarsky. For numerical solution of the adjoint equation, we introduce new variables and use an implicit difference splitting scheme. The peculiarity of the developed numerical model is the possibility of operative estimation of the «vulnerability» zone near a possible attack objective. Findings. The developed numerical model and computer program can be used for scientifically grounded assessment of the «vulnerability» zone near significant facilities in the event of possible attacks with the use of chemical (biological) agents. The constructed numerical model can be implemented on computers of small and medium power, which allows it to be widely used to solve the problems of this class when developing the emergency response plan. The results of the computational experiment are presented, which allow us to evaluate the possibilities of the proposed numerical model. Originality. An effective numerical model is proposed for calculating the «vulnerability» zone near the facility, which may be the target of a terrorist attack with the use of a chemical agent. The model is based on the numerical integration of the velocity potential equation and the equation adjoint to the equation of mass transfer of a chemically dangerous substance in the atmosphere. Practical value. The developed model can be used to organize protective actions near the target facility of a possible chemical attack by terrorists.
Complex of Numerical Models for Computation of Air Ion Concentration in Premises
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Biliaiev, Mykola M.; Tsygankova, Svetlana G.
EN: Purpose. The article highlights the question about creation the complex numerical models in order to calculate the ions concentration fields in premises of various purpose and in work areas. Developed complex should take into account the main physical factors influencing the formation of the concentration field of ions, that is, aerodynamics of air jets in the room, presence of furniture, equipment, placement of ventilation holes, ventilation mode, location of ionization sources, transfer of ions under the electric field effect, other factors, determining the intensity and shape of the field of concentration of ions. In addition, complex of numerical models has to ensure conducting of the express calculation of the ions concentration in the premises, allowing quick sorting of possible variants and enabling «enlarged» evaluation of air ions concentration in the premises. Methodology. The complex numerical models to calculate air ion regime in the premises is developed. CFD numerical model is based on the use of aerodynamics, electrostatics and mass transfer equations, and takes into account the effect of air flows caused by the ventilation operation, diffusion, electric field effects, as well as the interaction of different polarities ions with each other and with the dust particles. The proposed balance model for computation of air ion regime indoors allows operative calculating the ions concentration field considering pulsed operation of the ionizer. Findings. The calculated data are received, on the basis of which one can estimate the ions concentration anywhere in the premises with artificial air ionization. An example of calculating the negative ions concentration on the basis of the CFD numerical model in the premises with reengineering transformations is given. On the basis of the developed balance model the air ions concentration in the room volume was calculated. Originality. Results of the air ion regime computation in premise, which is based on numerical 2D CFD model and balance model, are presented. Practical value. A numerical CFD model and balance model for the computation of air ion regime allow calculating the ions concentration in the premises in the conditions of artificial air ionization taking into account the main physical factors determining the formation of ions concentration fields.
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.
Emergency Burning of Solid Rocket Propellant: Damage Risk Assessment to People in the Workplace
(Dnipro National University of Railway Transport named after Academician V. Lazaryan, Dnipro, 2020) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kalashnikov, Ivan V.
EN: Purpose. This work includes the development of a computer model to calculate the risk of thermal damage to people in the shop in case of emergency burning of solid rocket propellant. Methodology. To calculate the temperature field in the shop in order to determine the zones of thermal damage to workers in the building, the equation expressing the law of energy conservation was used. Based on this modeling equation, the temperature field in the shop is calculated in the presence of a source of heat emission – burning solid rocket propellant. To calculate the velocity field of air flow in the shop, taking into account the location of obstacles in the path of heat wave propagation, we used the model of vortex-free air motion – the equation of the velocity potential. A two-step finite difference scheme of conditional approximation is used to numerically solve the equation for the velocity potential. A difference splitting scheme was used to numerically solve the energy equation. At the first stage of construction of the difference splitting scheme of the two-dimensional energy equation into the system of one-dimensional equations is performed. Each one-dimensional equation allows you to calculate the temperature change in one coordinate direction. The point-to-point computation scheme is used to determine the temperature. When conducting a computational experiment, the air exchange in the building is taken into account. The risk assessment of thermal damage to personnel in the building is performed for different probabilities of the place of emergency combustion of solid rocket propellant. Findings. Using numerical model prediction of the potential risk areas of thermal damage to staff in the shop for a variety of emergency situations was performed. Originality. A computer model for rapid assessment of the potential risk of damage to people in the shop in case of emergency burning of solid rocket propellant was constructed. Practical value. The authors developed a code that allows you to quickly simulate the temperature fields formation in the shop in case of emergency burning of solid rocket propellant and to identify potential areas of thermal damages to workers based on this information. The developed computer program can be used to assess the risk of thermal damage in the chemical industry in case of emergency.
Evaluation of Gabions Usage Effectiveness for Industrial Facilities Protection Against Damage
(Український державний університет науки і технологій, Дніпро, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Kalashnikov, Ivan V.; Biliaiev, Mykola M.; Kozachyna, Vitalii A.
ENG: Purpose. In the extreme situations at industrial sites, various damaging factors may appear, such as the spread of toxic substances in the air, the creation of a fireball, etc., which pose a threat to the lives of workers and have a significant negative impact on the environment. That is why today, special attention is being paid to the problems associated with the spread of debris during a drone attack. At an industrial site where oil product storage facilities are located, the debris generated during an explosion can damage the tank building and cause a fire. In this regard, the main objective of the study is to evaluate the effectiveness of using gabion to reduce the risk of damage to the oil storage facility during the movement of drone debris. Methodology. To achieve this goal, the paper considers the problem of flying debris in the event of a drone explosion at an industrial site where oil storage facilities are located. The use of gabion with sand is proposed to protect the tank building from the throwing effect of debris. It is proposed to develop a mathematical model of the movement of a fragment in the path of which the gabion is located. The effect of gabion as a protective screen on reducing the air temperature near a neighboring oil storage facility in the event of a fire at an industrial site is also considered. A model of the dynamics of a point motion (Newton's second law) was used to mathematically describe the movement of the debris. Numerical integration of the modeling equations was performed using the Euler's method. The energy equation was used to model the process of thermal air pollution at an industrial site during a fire. Findings. In this work, the numerical model was programmed and a computer code was created. The programming language is FORTRAN. The code provides information on the speed of the fragment movement in different parts of each zone. On the basis of the constructed numerical model and the created code, parametric studies were carried out to determine the effectiveness of using gabion with sand to protect the oil storage facility from the effects of fragment. As an approximation, the case when the fragment after the explosion moves horizontally in the direction of the object was considered. The influence of the gabion height on the heating level of the wall of the oil storage facility located at an industrial site was analyzed. Originality. An effective mathematical model has been developed to evaluate the effectiveness of using gabion to protect the oil storage facility from damage by drone fragment. The proposed model allows determining the rational dimensions of the gabion to reduce the risk of damage to the tank wall. An effective computer model of thermal air pollution at an industrial site in the event of a fire at an oil storage facility is presented. Practical value. On the basis of the constructed mathematical model, a computer code was created to conduct a computational experiment to determine the effectiveness of using protective barriers (gabions) on the territory of an industrial site.
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 Models for Water Treatment Problems
(Український державний університет науки і технологій, Дніпро, 2025) Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kyrychenko, M. V.; Skuratov, M. O.; Chirkov, A. O.; Filonenko, H. K.
ENG: Purpose. Assessing the efficiency of water treatment in different structures is a problem of big importance. To solve this a problem, it is necessary to have mathematical models that allow to quickly obtain data on the cleaning effect in different structures. The aim of the work is to develop numerical models to determine the efficiency of water treatment in an aeration tanks, settlers and mixers. Methodology. For mathematical modeling of the process of water treatment in a bioreactor, balance equations were used. These equations allow to determine concentrations of substrate, activated sludge and dissolved oxygen in s structure. The Monod model is used to calculate the substrate oxidation process. To study effectiveness of water treatment process in vertical settler Euler’s equation were used with convective-diffusive equation. To simulate reagent mixing in mixer equation of potential and convective-diffusive equation were used. To solve governing equations finite- difference schemes of splitting were used. Findings. A tool for theoretical assessment mass transfer processes in aeration tank, vertical settler, mixer was developed. Originality. Effective numerical models to simulate water treatment in bioreactor, vertical settler, mixer were developed. Fundamental equations of Fluid Dynamics and Mass Transfer were used to build the models. Proposed models can be used in practice at the stage of «sketch designing». The models take into account the main physical parameters which influence the process of Mass Transfer and are quick computing. Practical value. The constructed mathematical model can be useful during the reconstruction and designing structures for water treatment. Computer programs have been developed to carry out numerical experiment. The results of a computer experiment are presented.
Minimization of the Chemical Pollution Level at the Working Zones in Open Areas Using Screens
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Biliaiev, Mykola M.; Rusakova, Tetiana I.; Shynkarenko, Viktor I.
ENG: Purpose. The scientific work aims to develop a new method for assessing the level of chemical air pollution in working zones located in open areas near highways using screens of different heights. Methodology. The analytical method for calculating the airflow velocity field near protective screens is based on the mathematical apparatus of the theory of complex variable functions, which allows obtaining the value of the velocity potential and the flow function, to calculate the velocity value at any point of the plane with a screen of different height. The obtained velocity field is used to calculate the level of carbon monoxide concentration in the numerical solution of the two-dimensional mass transfer equation. Findings. The developed program of numerical calculation allows conducting computational experiments on the effectiveness of the use of protective screens, taking into account changes in their geometry and meteorological conditions. The developed method based on the obtained concentration field makes it possible to carry out an assessment of the risk of chronic intoxication for the employees of the take-out trade, who are within the zone of the emission source (highway) for a long time. Originality. The regularities of changes in the concentration of carbon monoxide are established depending on the distance to the emission source at a height of 2 m from the ground in the presence of a screen of a certain height and in its absence. A risk assessment of chronic carbon monoxide intoxication has been carried out for take-out trade workers near the highway. It is shown that the presence of the screen reduces the risk of chronic CO intoxication by 10% as compared to its absence. Increasing the screen height to 1.8 m reduces the risk of chronic intoxication by 6% relatively to the situation when the screen height is 1.2 m. Practical value. The developed numerical-analytical method for calculating the level of chemical pollution in working zones in open areas and the program «Screen» created on its basis allow us to carry out a prompt forecast of atmospheric air pollution level with carbon monoxide taking into account the effectiveness of the screens. Quantitative results are necessary at the planning stage of trading places near highways, during the architectural-planned reorganization of adjacent developments.
Modeling of Biological Wastewater Treatment on the Basis of Quick-Computing Numerical Model
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2018) Biliaiev, Mykola M.; Lemesh, Maksym V.
EN: Purpose. The scientific paper involves the development of quick computing numerical model for prediction of output parameters of aeration tank. The numerical model may be used in predicting the effectiveness of aeration tank under different regimes of work. Methodology. To simulate the process of biological wastewater treatment in aeration tank numerical models were developed. The flow field in the aeration tank is simulated on the basis of potential flow model. 2-D transport equations are used to simulate substrate and sludge dispersion in the aeration tank. To simulate the process of biological treatment simplified model. For the numerical integration of transport equations implicit difference scheme was used. The difference scheme is built for splitting transport equations. Splitting of transport equation into two equations is carried out at differential level. The first equation of splitting takes into account the sludge or substrate movement along trajectories. The second splitting equation takes into account the diffusive process of substrate or sludge. To solve the splitting equations implicit difference scheme was used. For the numerical integration of potential flow equation the implicit scheme of conditional approximation was used. On the basis of constructed numerical model computer experiment was performed to investigate the process of biological treatment in aeration tank. Findings. Quick computing numerical model to simulate the process of biological treatment in the aeration tank was developed. The model can be used to obtain aeration tank parameters under different regimes of work. The developed model takes into account the geometrical form of the aeration tank. Originality. The numerical model which takes into account the geometrical form of aeration tank and fluid dynamics process was developed; the model takes into account substrate and sludge transport in aeration tank and process of biological treatment. Practical value. Efficient numerical model, so called «diagnostic models» was proposed for quick calculation of biological treatment process in aeration tank.
Numerical Determination of Horizontal Settlers Performance
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Biliaiev, Mykola M.; Kozachyna, Vitalii A.
EN: Purpose. Horizontal settlers are one of the most important elements in the technological scheme of water purification. Their use is associated with the possibility to pass a sufficiently large volume of water. The important task at the stage of their designing is evaluating of their effectiveness. Calculation of the efficiency of the settler can be made by mathematical modeling. Empirical, analytical models and techniques that are currently used to solve the problem, do not allow to take into account the shape of the sump and various design features that significantly affects the loyalty to a decision on the choice of the size of the settling tank and its design features. The use of analytical models is limited only to one-dimensional solutions, does not allow accounting for nonuniform velocity field of the flow in the settler. The use of advanced turbulence models for the calculation of the hydrodynamics in the settler complex forms now requires very powerful computers. In addition, the calculation of one variant of the settler may last for dozens of hours. The aim of the paper is to build a numerical model to evaluate the effectiveness of horizontal settling tank modified design. Methodology. Numerical models are based on: 1) equation of potential flow; 2) equation of inviscid fluid vortex flow; 3) equation of viscous fluid dynamics; 4) mass transfer equation. For numerical simulation the finite difference schemes are used. The numerical calculation is carried out on a rectangular grid. For the formation of the computational domain markers are used. Findings. The models allow calculating the clarification process in the settler with different form and different configuration of baffles. Originality. A new approach to investigate the mass transfer process in horizontal settler was proposed. This approach is based on the developed CFD models. Three fluid dynamics models were used for the numerical investigation of flows and waste waters purification. Practical value. The developed models have more capacity than the existing models in Ukraine. The developed models allow calculating quickly the efficiency of water purification in settlers. The models are not computationally expensive. Calculation time of one variant of the problem takes few seconds.
Numerical Modeling of Air Pollution From Dumps
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Biliaiev, Mykola M.; Rusakova, Tetiana I.; Kalashnikov, I. V.; Bondarenko, Iryna O.; Gunko, Elena Yu.
ENG: Purpose. Rock dumps are long-term sources of air pollution. A significant amount of harmful substances enters the atmosphere. Particularly intense is the pollution of atmospheric air due to dusting dumps. An important task is the development of methods for predicting the dynamics of atmospheric air pollution during the emission of harmful impurities from dumps. When developing methods for predicting the dynamics of air pollution from dumps. It is very important to create a universal model that would allow on a single computing platform to calculate the process of atmospheric air pollution for various impurities that are released from dumps. Another important problem is the choice of the place for optimal placement of future dumps in order to minimize their negative impact on the environment. Methodology. Numerical modeling of the formation of atmospheric pollution zones near rock dumps is based on the application of the equation of turbulent dispersion of an impurity in the atmosphere. To solve the problem of choosing the rational location of the dumps, the conjugate equation is used. Numerical integration is carried out using an implicit difference scheme. Findings. Numerical models are developed. The first numerical model allows one to evaluate the effect of rock dumps on air pollution. The second numerical model allows, on the basis of a one-time calculation, to determine the rational location of the future dump from the point of view of its minimal impact on air pollution. Originality. Two numerical models are proposed that are based on the application of the turbulent diffusion equation and the conjugate equation. These models make it possible to quickly determine the effect of rock dumps on air pollution. The models take into account the convective transport of the pollutant, atmospheric turbulent diffusion, the intensity of the emission of impurities from the dump. Practical value. The developed numerical models are implemented in the form of program codes. These program codes can be used when performing serial calculations on computers of low and medium power, i.e. computer technology, which is available to organizations involved in environmental issues in technologically saturated regions. When carrying out calculations based on the constructed numerical models, typical initial data are used regarding the intensity of the emission of impurities from dumps, weather conditions characteristic of a specific region of the country.
Numerical Simulation of Air Pollution in Case of Unplanned Ammonia Release
(Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Dnipro, 2017) Amelina, Larysa V.; Biliaiev, Mykola M.
EN: Purpose. Development fast calculating model which takes into account the meteorological parameters and buildings which are situated near the source of toxic chemical emission. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. Equation of potential flow is used to compute wind pattern among buildings. To solve equation for potential flow Samarskii implicit difference scheme is used. The implicit change – triangle difference scheme is used to solve equation of mass transfer. Numerical integration is carried out using the rectangular difference grid. Method of porosity technique («markers method») is used to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed 2D numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of pollutants in the atmosphere. The model takes into account the influence of buildings on pollutant dispersion. On the basis of the developed numerical models a computational experiment was carried out to estimate the level of toxic chemical pollution in the case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows to calculate the 2D wind pattern among buildings and pollutant dispersion in the case unplanned ammonia release. Model allows to perform fast calculations of the atmosphere pollution. Practical value. The model can be used when developing the PLAS (Emergency Response Plan).
Numerical Simulation of Pollution Dispersion in Urban Street
(Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Dnipro, 2017) Biliaiev, Mykola M.; Slavinska, O. S.; Kyrychenko, R. V.
EN: Purpose. The scientific paper solves the question of 2D numerical model development, which allows quick computation of air pollution in streets from vehicles. The aim of the work is numerical model development that would enable to predict the level of air pollution by using protective barriers along the road. Methodology. The developed model is based on the equation of inviscid flow and equation of pollutant transfer. Potential equation is used to compute velocity field of air flow near road in the case of protection barriers application. To solve equation for potential flow implicit difference scheme of «conditional approximation« is used. The implicit change – triangle difference scheme is used to solve equation of convective – diffusive dispersion. Numerical integration is carried out using the rectangular difference grid. Method of porosity technique («markers method») is used to create the form of comprehensive computational region. Emission of toxic gases from vehicle is modeled using Delta function for point source. Findings. Authors developed 2D numerical model. It takes into account the main physical factors affecting the process of dispersion of pollutants in the atmosphere when emissions of vehicle including protection barriers near the road. On the basis of the developed numerical models a computational experiment was performed to estimate the level of air pollution in the street. Originality. A numerical model has been created. It makes it possible to calculate 2D aerodynamics of the wind flow in the presence of noises and the process of mass transfer of toxic gas emissions from the motorway. The model allows taking into account the presence of the car on the road, the form of a protective barrier, the presence of a curb. Calculations have been performed to determine the contamination zone formed at the protective barrier that is located at the motorway. Practical value. An effective numerical model that can be applied in the development of environmental protection measures for the operation of road transport in the city is considered. The developed model allows estimating sizes, the form and intensity of a zone of pollution at a motorway.
Numerical Simulation of Toxic Chemical Dispersion after Accident at Railway
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Biliaiev, Mykola M.; Muntian, L. Ya.
EN: Purpose. This research focuses on the development of an applied numerical model to calculate the dynamics of atmospheric pollution in the emission of dangerous chemical substances in the event of transportation by railway. Methodology. For the numerical simulation of transport process of the dangerous chemical substance in the atmosphere the equation of convection-diffusion pollutant transport is used. This equation takes into account the effect of wind, atmospheric diffusion, the power of emission source, as well as the movement of the source of emission (depressurized tank) on the process of pollutant dispersion. When carrying out computing experiment one also takes into account the profile of the speed of the wind flow. For the numerical integration of pollutant transport in the atmosphere implicit finite-difference splitting scheme is used. The numerical calculation is divided into four steps of splitting and at each step of splitting the unknown value of the concentration of hazardous substance is determined by the explicit running account scheme. On the basis of the numerical model it was created the code using the algorithmic language FORTRAN. On the basis of the numerical model it was created the code using the algorithmic language FORTRAN. One conducted the computational experiments to assess the level of air pollution near the railway station «Illarionovo» in the event of a possible accident during transportation of ammonia. Findings. The proposed model allows you to quickly calculate the air pollution after the emission of chemically hazardous substance, taking into account the motion of the emission source. The model makes it possible to determine the size of the land surface pollution zones and the amount of pollutants deposited on a specific area. Using the developed numerical model it was estimated the environmental damage near the railway station «Illarionovo». Originality. One can use the numerical model to calculate the size and intensity of the chemical contamination zones after accidents on transport. Practical value. The numerical model, developed by authors, can be used to estimate the size and intensity of the chemical contamination zones during emergency on transport. The developed numerical model solves the problem of assessing the impact of emergency emission of ammonia near the railway station «Illarionovo».
Prediction of Atmosphere Pollution in Case of Emissions From Main Mine Fans
(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Biliaiev, Mykola M.; Bondarenko, Iryna O.; Rusakova, Tetiana I.; Shynkarenko, Viktor I.; Gabrіnets, Volodymyr O.
ENG: Purpose. Emissions from mine ventilation system can create intensive atmosphere air pollution. As a rule, a huge amount of dust from mine fan enters atmosphere low layers. An important task is the development of methods to assess levels of the atmosphere pollution near mines and settlements. To solve this problem it is important to have physically proved mathematical models. Nowadays to predict the atmosphere pollution near settlements which are effected by mine fan the empirical model OND–86 is used. This model does not take into account many important physical factors. So, the purpose of this study is the development of quick computing mathematical model to predict the atmosphere pollution in case of dust emissions from mine fan. Methodology. To predict levels of the atmosphere pollution in case of mine fan work 3D equation of dust convective – diffusive flow was used. This equation takes into account gravity fallout, wind velocity, atmosphere turbulent diffusion, location of dust emission source. To sole modeling equation the implicit difference scheme of splitting was used. Findings. Developed mathematical model allows quick prediction of the level of atmosphere pollution in case of dust emissions from mine ventilation fan. The models allow to obtain zones of contamination near settlements which are situated in vicinity of mine. Originality. The developed mathematical model takes into account a number of physical factors, which at the present time are not considered on the days when prediction of the atmosphere pollution in settlements near mine is carried out. Practical value. On the basis of the developed mathematical model program code was created. This code can be used for evaluation of atmosphere pollution in settlements which are effected mine fan emissions.
Quick computing CFD model to predict chemical pollution in room
(Український державний університет науки і технологій, Дніпро, 2024) 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 of Thermal Damage to People at Industrial Sites in Case of Emergency Burning Solid Propellant
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2020) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Kalashnikov, Ivan V.; Shevchenko, O. V.
EN: Purpose. This work involves the development of a numerical model for the calculation of areas of thermal damage to people in the event of solid propellant burning at the industrial site. Methodology. An equation expressing the law of energy conservation was used to solve the problem of determining the areas of thermal shock of people at the industrial site. A potential flow model was used to calculate the airflow velocity field in the presence of buildings at the industrial site where an emergency occurs. The numerical solution of the two-dimensional equation for the velocity potential is derived using the Liebmann method. This numerical model takes into account the uneven velocity field of the wind flow that is formed near industrial buildings. An implicit difference splitting scheme was used to numerically solve the energy equation. The physical splitting of a two-dimensional energy equation into a system of one-dimensional equations describing the temperature transfer in one coordinate direction has been carried out previously. At each splitting step, the unknown temperature value is determined by an explicit point-to-point computation scheme. Based on the numerical model built, the code using the FORTRAN algorithm language is created. Findings. Based on the developed numerical model, a computational experiment was conducted to evaluate the risk of thermal damage to people at the industrial site where solid propellants are produced. The dangerous areas for personnel are identified. Originality. An efficient numerical model has been developed to calculate the zones of thermal pollution in case of solid propellant burning. Practical value. Based on the developed mathematical model, a computer program was created, which allows performing serial calculations for determining the zones of thermal damage during emergencies at the chemically hazardous objects. The mathematical model developed can be used to design an emergency response plan for chemically hazardous objects.
Risk Assessment With the Use of the Monte-Carlo Method
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Amelina, Larysa V.; Biliaiev, Mykola M.; Berlov, Oleksandr V.; Cherednychenko, L. A.
EN: Purpose. This work involves the development of a numerical model for the calculation of chemical contamination zones in the event of ammonia accident at the pumping station, as well as a model for assessing the risk of damage and wound depth in the body in case of fragments scattering formed during the pipeline explosion at the pumping station. Methodology. To solve this problem, we used the mass transfer equation for the ammonia propagation in the air. A potential flow model is used to calculate the air flow velocity field in the presence of buildings at the ammonia pumping station. The numerical solution of the three-dimensional equation for the velocity potential is derived by the cumulative approximation method. When using this numerical model, the irregular field of wind flow velocity, the change in vertical atmospheric diffusion coefficient with altitude, the ammonia emission intensity, the emission point of the chemical substance were taken into account. A differential splitting scheme was used to numerically solve the ammonia transfer equation in the air. Physical splitting of the three-dimensional mass transfer equation to a system of equations describing the contaminant transfer in one coordinate direction is carried out beforehand. At each step of splitting, the unknown value of ammonia concentration is determined by an explicit scheme of point-to-point computation. A mathematical model for calculating the fragments scattering in case of emergency at the pumping station is considered. Findings. On the basis of the developed numerical model, a computational experiment was conducted to estimate the level of air pollution at the ammonia pumping station. The area of possible damage of people during the fragment scattering during the explosion at the ammonia pumping station was determined. Originality. A numerical model has been developed that allows calculating the chemical contamination zones in case of emergency ammonia emission at the pumping station. The model is complemented by assessment of impact zones in case of fragment scattering during the pumping station explosion. Practical value. Based on the developed mathematical model, a computer program was created, which allows performing serial calculations for determining the impact zones during emergency situations at the chemically hazardous objects. The mathematical model developed can be used to perform serial calculations during the development of emergency response plan for chemically hazardous objects.
Ієрархія математичних моделей для розрахунку аеротенків
(Український державний університет науки і технологій, Дніпро, 2026) Biliaiev, Mykola M.; Chirkov, A. O.
ENG: Purpose. Aeration tanks are widely used in wastewater treatment. Complex processes of mass transfer of impurities, activated sludge, and oxygen occur in an aeration tank. Therefore, it is very important to have specialized mathematical models that allow for a comprehensive consideration of complex multifactorial processes in aeration tanks. The aim of this work is to identify the advantages and disadvantages of mathematical models used to evaluate the efficiency of water treatment in aeration tanks, as well as to develop numerical models for analyzing the operation of aeration tanks. Methodology. System analysis methods used in accordance with hydrodynamics and mass transfer models in wastewater treatment tasks in aeration tanks. The solution of the hydrodynamics problem is based on the use of potential flow model. Mass transfer equations that take into account convective and diffusive transport are used to describe the process of impurity movement in an aeration tank. The development of numerical models is based on the use of the method of splitting modeling equations. Findings. Numerical models for calculating the efficiency of water purification in an aeration tank have been developed and implemented in software. These models are a modern tool for mathematical modeling of complex, multifactorial mass transfer processes in aeration tanks. Originality. Based on a systematic analysis, the advantages and disadvantages of the models used to analyze the efficiency of aeration tanks have been identified. The construction of effective numerical models for calculating hydrodynamics and mass transfer in aeration tanks has been considered. Practical value. The proposed numerical models of hydrodynamics and mass transfer in aeration tanks can be useful for rapid assessment of the efficiency of wastewater treatment in aeration tanks.