Science and Transport Progress

Computer 3D Modeling of the Process of Wastewater Treatment in a Settling Tank

Wed, 27 Dec 2023 00:00:00 +0200

Purpose. Settling tanks are widely used in technological schemes of wastewater treatment. As a rule, horizontal settling tanks are used in practice. However, to increase the efficiency of water treatment in a horizontal settling tank, additional elements can be used, which are placed in different places in the structure. When reconstructing such structures or designing them for new facilities, it is necessary to assess the efficiency of the settling tanks under different operating conditions. To solve this problem, mathematical models play an important role, including conducting physical experiments, which requires considerable time to obtain results. In the case of mathematical modeling of the water treatment process in a sedimentation tank, two problems need to be solved: the hydrodynamic problem and the mass transfer problem. The main purpose of this paper is to develop a 3DCFD model for calculating the impurity concentration field in a sedimentation tank. Methodology. A dynamic multifactorial numerical model was developed for computer calculation of the wastewater treatment process in a settling tank. The hydrodynamics of the wastewater flow in the settling tank was calculated on the basis of a three-dimensional equation for the velocity potential (potential motion model). The calculation of the impurity concentration field in the settling tank was determined by numerical integration of the three-dimensional mass transfer equation. This equation takes into account the non-uniformity of the flow velocity field in the settling tank, the diffusion process, and the gravitational deposition of the impurity in the structure. The numerical integration of the modeled equations was carried out by using finite-difference splitting schemes. Findings. The software implementation of the constructed mathematical model was carried out. The results of a computational experiment to study the process of wastewater treatment in a settling tank with visualization of the calculation results are presented. Originality. A multifactorial three-dimensional CFD model has been developed that allows to quickly assess the efficiency of the settling tank. Practical value. The proposed CFD model can be used in calculations in the design of wastewater treatment systems or to determine the efficiency of wastewater treatment under new operating conditions.

Analysis of the Mechanism for Selecting Organizational and Technological Solutions for Integrated Management of Construction Processes

А. О. Ichetovkin — Mon, 25 Dec 2023 00:00:00 +0200

Purpose. The main purpose of this article is to thoroughly substantiate the possibilities of implementing a mechanism for selecting organizational and technological solutions to achieve parametric criteria for managing construction processes, especially under conditions of uncertainty. To achieve this goal, we use a functional model of the system-integrated approach, which allows us to systematize and coordinate management functions at the level of individual processes. Methodology. The study is based on the introduction of new requirements for standardization in the construction industry, in particular, on the use of the parametric method. This method can improve management strategies, methods, and technologies, as well as facilitate the implementation of innovative organizational and technological solutions. As a result, the quality and volume of construction can be improved, which, in turn, will help overcome the crisis and develop the construction industry. The management process involves achieving a key goal, namely the efficiency of project implementation, while construction has certain specifics that complicate the management process and require the use of more complex, integrated, and multi-directional organizational and technological solutions. Findings. In the current economic environment, which provides for both an increase in the number of risks in the construction sector and the size of their possible consequences, in the context of increasing (expanding the list) of quality requirements for construction projects, there is a reasonable need to search for and improve organizational and technological solutions in order to apply new approaches to the management of construction processes related to the practical implementation of the results of modern scientific and methodological research. The results obtained, however, indicate that the use of the parametric method creates new challenges for the efficiency of management in the construction industry. The increased number of management decision alternatives, identification of risks and improvement of consequence forecasting processes may cause certain difficulties. On the other hand, the lack of clear requirements can lead to increased costs and risks. Originality. The paper substantiates the necessity of using a system-wide algorithmic mechanism for the effective management of construction processes under conditions of uncertainty. This is important for adapting to modern challenges and ensuring the sustainable development of the construction industry. Practical value. The study makes it possible to determine the compliance of organizational and technological solutions with the established criteria and compare them to select the most effective one, in particular in terms of cost, efficiency and risk mitigation.

Tools for the Involvement of Construction and Demolition Waste in the Repeated Production Cycle

A. A. Shuvaev — Fri, 22 Dec 2023 00:00:00 +0200

Purpose. This paper aims to analyze and classify construction and demolition waste. It is necessary that this classification not only reflects statistical data on waste generation, but also serves as an information basis for the integrated waste management system (IWMS). The main task of this system is to maximize the involvement of waste in economic recycling and to objectively reflect the technological capabilities of its processing. This is extremely important in the context of the implementation of European waste management principles and the implementation of the National Waste Management Strategy in Ukraine until 2030. Methodology. The article considers the problems of construction waste management within the framework of the National Waste Management Strategy in Ukraine until 2030, which provides for the implementation of measures and principles of waste management, including construction waste. The author analyzes the management problems in the field of construction and demolition waste, which substantiates the need to classify construction waste with the simultaneous harmonization of processing methods and technologies. Construction activities are inextricably linked to the management of various types of resources, among which secondary materials play a key role in the implementation of construction processes. The ability to effectively manage the flows of these secondary resources is critical to ensuring the sustainability and efficiency of construction production. In this context, the study of the importance of managing the flows of secondary resources becomes an integral part of strategies for optimizing construction processes. Findings. Construction waste from the demolition of buildings and structures is unique due to its size and the need to prepare it for primary crushing. This is especially true in the context of implementing the concept of renovation of the outdated housing stock. Various static and dynamic methods of destruction of building materials, in particular, impact and vibration, have been investigated, with dynamic methods being characterized by lower energy consumption. Originality. The work reflects the formation of theoretical and methodological directions based on the use of recycled materials in construction, as well as a comparative characterization of various methods of destruction of building materials. Practical value. The possibilities of recycling construction waste, in particular, their maximum involvement in recycling, which meets the goals of the Strategy of Ukraine, provides 50% of waste recycling.

Determination of Parameters for Limiting Longitudinal Acceleration to Optimize Energy Consumption for Train Traction

D. V. Bobyr, E. B. Bodnar, D. M. Kisliy, A. Y. Desiak — Tue, 26 Dec 2023 00:00:00 +0200

Purpose. The main purpose of the article is to improve traction calculations using mathematical modeling when solving the equation of train motion. The train model is adapted to optimize the parameters of train movement during speed gain with the determination of functional relationships between the power of the locomotive power plant and the profile of the track section with the consumption of energy resources by the locomotive. Methodology. Modern methods of mathematical modeling were used to solve the tasks. The modeling of the power plant operation was performed using interpolation and approximation methods. The simulation modeling method was used to create a model of the electrical part of the diesel locomotive transmission. The method of integrating the differential equation of motion was used to calculate the parameters and nature of the train's movement and the problem was solved, which consists in finding a solution to this equation over the length of the traction section, taking into account the variable values of the locomotive power and the slopes of the track profile. Findings. To analyze the results of traction calculations, we obtained such indicators as technical speed and diesel fuel consumption, and compared these indicators. The results show that in the case of acceleration limitation, there is a decrease in diesel fuel consumption at almost unchanged technical speed. Originality. The improvement of energy efficiency of train operation has been further developed, namely, the functional dependence of the relative power of the locomotive power plant, which takes into account the actual profile of the site, has been obtained, which makes it possible to determine energy-saving modes of locomotive control and reduce energy consumption, load on the diesel engine and elements of the diesel locomotive traction transmission during transient modes, which, in turn, in addition to saving diesel fuel, will affect the reliability of the power plant elements. The practical value of the study is to save diesel fuel in the modes of movement that provide speed gain and increase the reliability of the power plant due to reduced load.

Determination of Energy-Optimized Locomotive Control During Train Acceleration

D. M. Kisliy, A. Y. Desiak, D. V. Bobyr, E. B. Bodnar — Wed, 27 Dec 2023 00:00:00 +0200

Purpose. In this article, the authors aim to improve the mathematical model of train movement by adapting the model to determine the values of diesel power at the corresponding values of train acceleration and different modes of train operation. Based on the model, it is planned to build and analyze two-parameter dependencies of locomotive control during acceleration, which provide steady acceleration on different track profile slopes for different values of train weight, which will allow for more rational management of the locomotive fleet with strict adherence to the train schedule and minimal diesel fuel consumption for traction. Methodology. To achieve this goal, we used the method of system analysis, nonlinear programming, and numerical methods for solving differential equations of train motion, taking into account that the integration of the equation of train motion can be carried out by path, time, and speed, depending on the initially set task in traction calculations. Calculations were performed for different modes and phases of train operation. Findings. To analyze the results, we compared the obtained traction calculations, such as technical speed, travel time, and fuel consumption. To solve the problem of traction calculations, we chose the Maple software package, which allowed us not only to numerically evaluate the results of solving the two-parameter mathematical model, but also to graphically and visually, which greatly simplifies their perception. The obtained results of the calculations indicate a decrease in energy consumption. Originality. The model of train movement has been further developed, taking into account the adaptation to determine the values of diesel power consumption in the case of steady-state values of train acceleration depending on the weight of the train and the slopes of the track profile. Practical value. The expediency of the study is to save energy resources, in particular diesel fuel, for train traction and allows more accurate adherence to the train schedule, which, in turn, affects traffic safety in general.