Purpose. This study is aimed at determining the vertical dynamics of supporting structures of freight cars made of round pipes. Methodology. Mathematical modeling of the dynamic loading of the supporting structures of the main types of freight cars made of round pipes (gondola car, covered car, flat car, hopper car) was carried out. The studies were carried out in a plane coordinate system – the XZ plane. At the same time, it was taken into account that the car is moving in an elastic-viscous track so that the reactions of the track are proportional to both its deformation and the rate of this deformation. The studies were carried out for the case of empty cars. The joint inequality is described by a periodic function. The calculation was performed at a speed of 80 km/h. Differential equations of motion were solved in the MathCad software package using the Runge-Kutta method. Findings. Based on the mathematical modeling of the dynamic loading of the supporting structures of cars made of round pipes, the main indicators of their dynamics were obtained: accelerations acting on the supporting structures in the mass center, forces acting in the spring suspension of bogies, dynamics coefficients. For gondola car, covered car, and hopper car, the acceleration at the mass center of the supporting structure is within 0.4 g, and for a flat car – 0.5 g. It was found that the obtained indicators of the dynamics of cars made of round pipes are within the permissible limits. The accelerations acting on the supporting structures of cars made of round pipes are almost the same as those obtained for prototype cars. At the same time, the motion of cars is assessed as "excellent" for gondola car, covered car, and hopper car and "good" for flat car. Originality. Mathematical modeling of the dynamic loading of the supporting structures of cars from round pipes was carried out and the main indicators of their dynamics were obtained. Practical value. The research carried out will contribute to the creation of recommendations for the design of supporting structures of freight cars of round pipes, and can also be useful developments in the creation of innovative car designs.
{"title":"Research of the Vertical Dynamics of the Supporting Structures of Freight Cars Made of Round Pipes","authors":"O. Fomin, A. Lovska","doi":"10.15802/stp2021/227223","DOIUrl":"https://doi.org/10.15802/stp2021/227223","url":null,"abstract":"Purpose. This study is aimed at determining the vertical dynamics of supporting structures of freight cars made of round pipes. Methodology. Mathematical modeling of the dynamic loading of the supporting structures of the main types of freight cars made of round pipes (gondola car, covered car, flat car, hopper car) was carried out. The studies were carried out in a plane coordinate system – the XZ plane. At the same time, it was taken into account that the car is moving in an elastic-viscous track so that the reactions of the track are proportional to both its deformation and the rate of this deformation. The studies were carried out for the case of empty cars. The joint inequality is described by a periodic function. The calculation was performed at a speed of 80 km/h. Differential equations of motion were solved in the MathCad software package using the Runge-Kutta method. Findings. Based on the mathematical modeling of the dynamic loading of the supporting structures of cars made of round pipes, the main indicators of their dynamics were obtained: accelerations acting on the supporting structures in the mass center, forces acting in the spring suspension of bogies, dynamics coefficients. For gondola car, covered car, and hopper car, the acceleration at the mass center of the supporting structure is within 0.4 g, and for a flat car – 0.5 g. It was found that the obtained indicators of the dynamics of cars made of round pipes are within the permissible limits. The accelerations acting on the supporting structures of cars made of round pipes are almost the same as those obtained for prototype cars. At the same time, the motion of cars is assessed as \"excellent\" for gondola car, covered car, and hopper car and \"good\" for flat car. Originality. Mathematical modeling of the dynamic loading of the supporting structures of cars from round pipes was carried out and the main indicators of their dynamics were obtained. Practical value. The research carried out will contribute to the creation of recommendations for the design of supporting structures of freight cars of round pipes, and can also be useful developments in the creation of innovative car designs.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128835007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Purpose. The staged connections of the stringers of railway bridge track-way have the simplest design, but some design flaws result in numerous defects. The purpose of this work is an investigation of the previously proposed methods of strengthening the support node for the stringers of the track-way of a staged communication, as well as investigation of the work of the reinforcement proposed by the author. Methodology. The author analyzes the condition of metal bridges operated on the railway. It was found that the decisive element in determining the load capacity of the entire bridge are the stringers of the track-way. To achieve this goal, the author analyzed the stress-strain state of the support node of the stringer on the cross-bar without and with reinforcement using the finite element method. The discovered rational parameters of the proposed reinforcement unit. The calculations were performed in Selena software. Findings. Stress-strain state of the connection point of the stringers with the floor beamsnode on condition of their staged position was obtained and analyzed. The author selected the rational parameters of the reinforcement elements of the stringer support node for the staged communication and analyzed stress-strain state of the new connection node of the stringers with the floor beams at their staged location based on typical spans of Proiektstalkonstruktsii LLC (PSK). The analysis shows that after the proposed reinforcement, the maximum stresses in the horizontal legs of the flange angles of the stringers and floor beams, which destroyed the structures, decreased by 43–73%. Originality. The work analyzes the stress-strain state of metal stringers of the track-way of the staged location taking into account the joint work of stringers with load-bearing trusses, as well as the stress-strain state of the proposed reinforcement of the support node of metal stringers with the identification of rational parameters. Practical value. This method of repair with reinforcement is recommended as the most rational for a bridge over the Inhulets river at 109 km of the Verkhivtseve – Dolynska Railway (contract No. 94/2011–TsTekh–177/2011–ETU dated 09/30/2011). Based on these results, a patent for utility model No. 109806 dated 09/12/2016 was issued.
{"title":"Operation Study of the Node of Stringer Staged Connection Point of the Railway Bridge Track-Way","authors":"S. Kliuchnyk","doi":"10.15802/stp2021/227222","DOIUrl":"https://doi.org/10.15802/stp2021/227222","url":null,"abstract":"Purpose. The staged connections of the stringers of railway bridge track-way have the simplest design, but some design flaws result in numerous defects. The purpose of this work is an investigation of the previously proposed methods of strengthening the support node for the stringers of the track-way of a staged communication, as well as investigation of the work of the reinforcement proposed by the author. Methodology. The author analyzes the condition of metal bridges operated on the railway. It was found that the decisive element in determining the load capacity of the entire bridge are the stringers of the track-way. To achieve this goal, the author analyzed the stress-strain state of the support node of the stringer on the cross-bar without and with reinforcement using the finite element method. The discovered rational parameters of the proposed reinforcement unit. The calculations were performed in Selena software. Findings. Stress-strain state of the connection point of the stringers with the floor beamsnode on condition of their staged position was obtained and analyzed. The author selected the rational parameters of the reinforcement elements of the stringer support node for the staged communication and analyzed stress-strain state of the new connection node of the stringers with the floor beams at their staged location based on typical spans of Proiektstalkonstruktsii LLC (PSK). The analysis shows that after the proposed reinforcement, the maximum stresses in the horizontal legs of the flange angles of the stringers and floor beams, which destroyed the structures, decreased by 43–73%. Originality. The work analyzes the stress-strain state of metal stringers of the track-way of the staged location taking into account the joint work of stringers with load-bearing trusses, as well as the stress-strain state of the proposed reinforcement of the support node of metal stringers with the identification of rational parameters. Practical value. This method of repair with reinforcement is recommended as the most rational for a bridge over the Inhulets river at 109 km of the Verkhivtseve – Dolynska Railway (contract No. 94/2011–TsTekh–177/2011–ETU dated 09/30/2011). Based on these results, a patent for utility model No. 109806 dated 09/12/2016 was issued.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126877997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Biliaiev, M. Lemesh, V. Zadoia, P. Mashykhina, L. Tatarko, Z. Yakubovska
Purpose. The main purpose of the article is to develop a numerical model for the analysis of the process of biological wastewater treatment in a reactor with a mobile biocenosis. Methodology. For mathematical modeling of the process of biological wastewater treatment in a reactor with a moving biocenosis, a hydrodynamic model of a non-viscous vortex-free flow is used. We calculated the boundary conditions for the modeling equation on the surfaces of the bioreactor, solid walls, and the upper surface; at the inlet boundary; at the outlet boundary from the building. To calculate the process of movement of activated sludge and substrate in the bioreactor, a mass transfer model is used, which takes into account the convective-diffusion movement of the substrate and activated sludge. The process of biological water purification in that part of the bioreactor where there are no mobile biocenosis carriers will be calculated based on the Monod model. The process of biological water purification in the part of the bioreactor where there are mobile carriers is calculated on the basis of an empirical model in three stages. The first stage is determined using the Harremoes model. At the second stage, the rate of substrate «consumption» in the biofilm is calculated. At the third stage, the change in the substrate concentration in the zone where the biocenosis carriers are located is determined due to convective movement, substrate diffusion in the flow and its destruction in the biofilm on the carriers. The chaotic motion of biocenosis carriers in the reactor is modeled based on the parabolic diffusion equation. Finite-difference schemes are used for numerical integration of modeling equations. Findings. The software implementation of the constructed numerical model is carried out. A computational experiment to determine the efficiency of biological wastewater treatment in different parts of the bioreactor was conducted. Originality. An effective multifactorial numerical model has been created, which allows quick analysis of the efficiency of biological wastewater treatment in an aeration tank with mobile biocenosis carriers. Practical value. The created two-dimensional numerical model can be used for serial calculations at the stage of designing biological wastewater treatment systems and analysis of the efficiency of bioreactors under different operating conditions.
{"title":"Simulation of Biological Wastewater Treatment in Aerotanks with Moving Biocenosis","authors":"M. Biliaiev, M. Lemesh, V. Zadoia, P. Mashykhina, L. Tatarko, Z. Yakubovska","doi":"10.15802/stp2021/227358","DOIUrl":"https://doi.org/10.15802/stp2021/227358","url":null,"abstract":"Purpose. The main purpose of the article is to develop a numerical model for the analysis of the process of biological wastewater treatment in a reactor with a mobile biocenosis. Methodology. For mathematical modeling of the process of biological wastewater treatment in a reactor with a moving biocenosis, a hydrodynamic model of a non-viscous vortex-free flow is used. We calculated the boundary conditions for the modeling equation on the surfaces of the bioreactor, solid walls, and the upper surface; at the inlet boundary; at the outlet boundary from the building. To calculate the process of movement of activated sludge and substrate in the bioreactor, a mass transfer model is used, which takes into account the convective-diffusion movement of the substrate and activated sludge. The process of biological water purification in that part of the bioreactor where there are no mobile biocenosis carriers will be calculated based on the Monod model. The process of biological water purification in the part of the bioreactor where there are mobile carriers is calculated on the basis of an empirical model in three stages. The first stage is determined using the Harremoes model. At the second stage, the rate of substrate «consumption» in the biofilm is calculated. At the third stage, the change in the substrate concentration in the zone where the biocenosis carriers are located is determined due to convective movement, substrate diffusion in the flow and its destruction in the biofilm on the carriers. The chaotic motion of biocenosis carriers in the reactor is modeled based on the parabolic diffusion equation. Finite-difference schemes are used for numerical integration of modeling equations. Findings. The software implementation of the constructed numerical model is carried out. A computational experiment to determine the efficiency of biological wastewater treatment in different parts of the bioreactor was conducted. Originality. An effective multifactorial numerical model has been created, which allows quick analysis of the efficiency of biological wastewater treatment in an aeration tank with mobile biocenosis carriers. Practical value. The created two-dimensional numerical model can be used for serial calculations at the stage of designing biological wastewater treatment systems and analysis of the efficiency of bioreactors under different operating conditions.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127918674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Purpose. Based on the research work of units and parts of rolling stock undercarriage in transient modes of emergency situations it is proposed to optimize the sequential placing of peripheral contactless devices for technical control of locomotives and cars on railway lines. Methodology. Investigation of transient processes of temperature increase of faulty axle bearings of locomotives and cars during remote technical diagnosing allows one to organize theory and hardware construction of the peripheral systems for testing the rolling stock on the move. Automatic control of the technical state of the rolling stock on the move – the last and in some cases the only possible process step, which allows revealing unacceptable defects in rolling units and thereby prevent emergencies in railway transport. Findings. Based on the research it was proposed a solution to the optimization problem of placing peripheral control devices of rolling stock when moving according to the criteria of the linear and exponential nature of heating defective axle boxes of wheelsets and other units of undercarriage. The risks of train stop on the railway line because of the erroneous classification of normally heated axle boxes as overheated, as well as the consequences of classification of overheated axle box as normally heated axle boxes were evaluated. Originality. Optimization model of placing peripheral control devices based on probabilistic criteria for evaluating the degree of permissible risk that, at a minimum, should not be exceeded during the transition to control technical means. A functional block diagram of test hardware diagnostics for the wheelsets when determining the gradations of digital indicators of defects was proposed. Practical value. The value of the results obtained lies in the improvement of a method of placing technical control peripheral devices and diagnosing rolling stock when determining the distance between the control stations in the same direction and organizing tracking modes for railcars with developing defects. From a technical point, reduced error probability is directly related to traffic safety and diagnostic algorithms.
{"title":"Improving the Methodology of Placing Peripheral Devices for Monitoring the Technical Condition of Rolling Stock","authors":"V. Burchenkov","doi":"10.15802/stp2021/230220","DOIUrl":"https://doi.org/10.15802/stp2021/230220","url":null,"abstract":"Purpose. Based on the research work of units and parts of rolling stock undercarriage in transient modes of emergency situations it is proposed to optimize the sequential placing of peripheral contactless devices for technical control of locomotives and cars on railway lines. Methodology. Investigation of transient processes of temperature increase of faulty axle bearings of locomotives and cars during remote technical diagnosing allows one to organize theory and hardware construction of the peripheral systems for testing the rolling stock on the move. Automatic control of the technical state of the rolling stock on the move – the last and in some cases the only possible process step, which allows revealing unacceptable defects in rolling units and thereby prevent emergencies in railway transport. Findings. Based on the research it was proposed a solution to the optimization problem of placing peripheral control devices of rolling stock when moving according to the criteria of the linear and exponential nature of heating defective axle boxes of wheelsets and other units of undercarriage. The risks of train stop on the railway line because of the erroneous classification of normally heated axle boxes as overheated, as well as the consequences of classification of overheated axle box as normally heated axle boxes were evaluated. Originality. Optimization model of placing peripheral control devices based on probabilistic criteria for evaluating the degree of permissible risk that, at a minimum, should not be exceeded during the transition to control technical means. A functional block diagram of test hardware diagnostics for the wheelsets when determining the gradations of digital indicators of defects was proposed. Practical value. The value of the results obtained lies in the improvement of a method of placing technical control peripheral devices and diagnosing rolling stock when determining the distance between the control stations in the same direction and organizing tracking modes for railcars with developing defects. From a technical point, reduced error probability is directly related to traffic safety and diagnostic algorithms.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126298296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Amelina, M. Biliaiev, O. Berlov, O. Verhun, T. Rusakova
Purpose. This work provides for the development of a hydraulic model for calculating the unsteady ammonia outflow from a damaged pipeline and the implementation of this model into a numerical model for predicting emergency air pollution. Methodology. To solve the problem, the calculated dependencies of the pressure flow hydraulics were used. An empirical model to calculate the evaporation of ammonia from a damaged pipeline was also used. To calculate the process of spreading ammonia in atmospheric air, a three-dimensional equation of convective-diffusion transfer of impurities was used. Mathematical modeling of the spread of ammonia from a damaged pipeline takes into account the change with height of the wind flow velocity, as well as the change with height of the vertical coefficient of atmospheric diffusion, the dynamics of changes over time in the intensity of ammonia leakage from the damaged pipeline. For the numerical solution of the three-dimensional differential equation for the transfer of ammonia in atmospheric air, its physical splitting is carried out: an equation that describes the transport of an impurity due to convection is singled out separately, an equation that describes the transport of an impurity due to atmospheric diffusion and separately an equation that describes a change in the ammonia concentration in air due to the action of the emission source. The McCormack method is used to numerically integrate the equation for the convective transfer of ammonia in air. The Richardson method is used to numerically integrate the equation of diffusion transfer of an impurity. The Euler method is used to numerically integrate the equation that describes the change in ammonia concentration under the influence of an emission source. Findings. Based on the developed model of unsteady ammonia outflow from the damaged pipeline and the created numerical model of ammonia propagation in the atmospheric air, a computational experiment was carried out to assess the level of atmospheric air and underlying surface pollution in the event of an emergency ammonia outflow in the section where the Tolyatti – Odessa ammonia pipeline crosses the Dnipro River. Data on non-stationary environmental pollution were obtained. Originality. A mathematical model that allows calculating the unsteady process of ammonia outflow from a damaged pipeline has been developed. A numerical model is proposed to determine the areas of contamination during an emergency ammonia outflow from the Tolyatti – Odessa ammonia pipeline. Practical value. Based on the developed model, a code has been created that makes it possible to promptly predict the environmental pollution dynamics during an emergency ammonia outflow. The proposed mathematical model can be used in the development of emergency response plan for chemically hazardous facilities.
{"title":"Modeling of Environmental Pollution by Ammonia Emission from a Damaged Pipeline","authors":"L. Amelina, M. Biliaiev, O. Berlov, O. Verhun, T. Rusakova","doi":"10.15802/stp2021/229167","DOIUrl":"https://doi.org/10.15802/stp2021/229167","url":null,"abstract":"Purpose. This work provides for the development of a hydraulic model for calculating the unsteady ammonia outflow from a damaged pipeline and the implementation of this model into a numerical model for predicting emergency air pollution. Methodology. To solve the problem, the calculated dependencies of the pressure flow hydraulics were used. An empirical model to calculate the evaporation of ammonia from a damaged pipeline was also used. To calculate the process of spreading ammonia in atmospheric air, a three-dimensional equation of convective-diffusion transfer of impurities was used. Mathematical modeling of the spread of ammonia from a damaged pipeline takes into account the change with height of the wind flow velocity, as well as the change with height of the vertical coefficient of atmospheric diffusion, the dynamics of changes over time in the intensity of ammonia leakage from the damaged pipeline. For the numerical solution of the three-dimensional differential equation for the transfer of ammonia in atmospheric air, its physical splitting is carried out: an equation that describes the transport of an impurity due to convection is singled out separately, an equation that describes the transport of an impurity due to atmospheric diffusion and separately an equation that describes a change in the ammonia concentration in air due to the action of the emission source. The McCormack method is used to numerically integrate the equation for the convective transfer of ammonia in air. The Richardson method is used to numerically integrate the equation of diffusion transfer of an impurity. The Euler method is used to numerically integrate the equation that describes the change in ammonia concentration under the influence of an emission source. Findings. Based on the developed model of unsteady ammonia outflow from the damaged pipeline and the created numerical model of ammonia propagation in the atmospheric air, a computational experiment was carried out to assess the level of atmospheric air and underlying surface pollution in the event of an emergency ammonia outflow in the section where the Tolyatti – Odessa ammonia pipeline crosses the Dnipro River. Data on non-stationary environmental pollution were obtained. Originality. A mathematical model that allows calculating the unsteady process of ammonia outflow from a damaged pipeline has been developed. A numerical model is proposed to determine the areas of contamination during an emergency ammonia outflow from the Tolyatti – Odessa ammonia pipeline. Practical value. Based on the developed model, a code has been created that makes it possible to promptly predict the environmental pollution dynamics during an emergency ammonia outflow. The proposed mathematical model can be used in the development of emergency response plan for chemically hazardous facilities.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"192 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126104455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Biliaiev, M. Lemesh, O. Gunko, V. Zadoia, P. Mashykhina, Z. Yakubovska
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.
{"title":"3D MODELING OF BIOLOGICAL WASTEWATER TREATMENT IN AERATION TANK","authors":"M. Biliaiev, M. Lemesh, O. Gunko, V. Zadoia, P. Mashykhina, Z. Yakubovska","doi":"10.15802/STP2020/224619","DOIUrl":"https://doi.org/10.15802/STP2020/224619","url":null,"abstract":"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.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"163 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127524116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Bodnar, О. B. Ochkasov, Y. B. Bodnar, D. Bobyr, M. V. Ocheretniuk
Purpose. The work is aimed to assess the influence of locomotive service systems on the indicators of their use and operation organization of the locomotive depot. Methodology. To achieve this purpose the calculation of operational indicators of locomotives of series 2TE116 and TE33AS in the conditions of locomotive depot is performed. The simulation model of the locomotive repair shop has been improved. Using the methods of the queuing systems theory, simulation modeling of the locomotive repair shop with service and schedule preventive systems for locomotive service was performed. Findings. The program of locomotives repair at schedule preventive and service systems is calculated. Based on the simulation results of the repair shop operation, we compared the influence of operation and repair on the locomotive depot operation for two different approaches to the organization of locomotives maintenance. The simulation model of the locomotive repair shop allows further comparative analysis of the use of different series of locomotives in the depot. The analysis of the results obtained demonstrates that the proposed approach to modeling the maintenance and repair of a diesel locomotive fleet can be improved by determining the reliability indicators when locomotives arrive for scheduled and unscheduled repairs. Originality. We improved the simulation model of the locomotive repair shop, which allows analyzing the influence of operational factors on the system of locomotive repair, in order to select a rational system of the locomotive fleet maintenance. Practical value. The results obtained make it possible to analyze the influence of the operation and repair indicators of locomotives on the operation of the locomotive depot and to determine the feasibility of using the selected traction rolling stock at a given service area. The results obtained indicate that the use of TE33AS diesel locomotives with a service system should reduce the residence time for all types of maintenance and repairs.
{"title":"RESEARCH OF INFLUENCE OF LOCOMOTIVE SERVICE SYSTEM ON THE OPERATION ORGANIZATION OF LOCOMOTIVE DEPOT","authors":"B. Bodnar, О. B. Ochkasov, Y. B. Bodnar, D. Bobyr, M. V. Ocheretniuk","doi":"10.15802/stp2020/218609","DOIUrl":"https://doi.org/10.15802/stp2020/218609","url":null,"abstract":"Purpose. The work is aimed to assess the influence of locomotive service systems on the indicators of their use and operation organization of the locomotive depot. Methodology. To achieve this purpose the calculation of operational indicators of locomotives of series 2TE116 and TE33AS in the conditions of locomotive depot is performed. The simulation model of the locomotive repair shop has been improved. Using the methods of the queuing systems theory, simulation modeling of the locomotive repair shop with service and schedule preventive systems for locomotive service was performed. Findings. The program of locomotives repair at schedule preventive and service systems is calculated. Based on the simulation results of the repair shop operation, we compared the influence of operation and repair on the locomotive depot operation for two different approaches to the organization of locomotives maintenance. The simulation model of the locomotive repair shop allows further comparative analysis of the use of different series of locomotives in the depot. The analysis of the results obtained demonstrates that the proposed approach to modeling the maintenance and repair of a diesel locomotive fleet can be improved by determining the reliability indicators when locomotives arrive for scheduled and unscheduled repairs. Originality. We improved the simulation model of the locomotive repair shop, which allows analyzing the influence of operational factors on the system of locomotive repair, in order to select a rational system of the locomotive fleet maintenance. Practical value. The results obtained make it possible to analyze the influence of the operation and repair indicators of locomotives on the operation of the locomotive depot and to determine the feasibility of using the selected traction rolling stock at a given service area. The results obtained indicate that the use of TE33AS diesel locomotives with a service system should reduce the residence time for all types of maintenance and repairs.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113954101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"IMPROVEMENT OF THE METHODOLOGY FOR RATIONAL PARAMETERS DETERMINATION OF THE CAPACITIVE ENERGY STORAGE FOR THE METRO TRAIN","authors":"A. Sulym, P. Khozia","doi":"10.15802/stp2020/218603","DOIUrl":"https://doi.org/10.15802/stp2020/218603","url":null,"abstract":"","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115631411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Biliaiev, M. Lemesh, V. V. Biliaeva, P. Mashykhina, Z. Yakubovska
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.
{"title":"COMPUTER SIMULATION OF BIOLOGICAL WASTEWATER TREATMENT PROCESSES IN AEROTANKS WITH PLATES","authors":"M. Biliaiev, M. Lemesh, V. V. Biliaeva, P. Mashykhina, Z. Yakubovska","doi":"10.15802/stp2020/218302","DOIUrl":"https://doi.org/10.15802/stp2020/218302","url":null,"abstract":"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.","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132615455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"SIMULATION OF WASTE WATER TREATMENT BASED ON CFD MODEL: EXPRESS CALCULATION","authors":"V. Kozachyna, O. Hromova, O. Hunko, L. Tatarko","doi":"10.15802/stp2020/218310","DOIUrl":"https://doi.org/10.15802/stp2020/218310","url":null,"abstract":"","PeriodicalId":120413,"journal":{"name":"Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115592616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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