Proceedings of Odessa Polytechnic University

Research of hybrid energy supply system with renewable energy sources.

Hennadii Balasanian — 2024-11-15

The experimental database of climatic parameters from the meteorological station of the Odesa Polytechnic National University was processed for their further use to assess the energy potential of solar and wind energy in the Odessa region. The Weibull distribution parameters were found - the shape parameter and the scale parameter, which characterizes the repeatability of wind speed. The probability of wind speed repeatability was calculated based on the found Weibull distribution parameters, which provided more objective results for determining the power of a wind turbine compared to using the average wind speed. A methodology has been developed for determining the optimal parameters and configuration of an autonomous hybrid energy supply system with renewable energy sources for an individual household based on the criterion of minimum capital investments in generating capacity. It has been investigated that seasonal differences in the energy potential of the sun and wind contribute to the combination of these renewable energy sources into a single hybrid system and create additional advantages for their operation. The dependence of the optimal configuration and parameters of the hybrid system on the energy potential of the wind in the region has been obtained. The distributions of electricity production between wind turbines and solar panels by months of the year at a given average annual wind speed, taking into account the change in wind energy potential by months, are presented. It is determined that the variable nature of solar and wind resources can be fully compensated by optimal integration of two different sources into a single energy system. It was found that under the condition of autonomous operation of the hybrid system, the excess energy potential is not always used, because it is technically difficult to ensure seasonal accumulation of electricity. The utilization factor of the installed capacity of the hybrid system was 0.58. The distributions of electricity production between wind turbines and solar panels by months of the year at a given average annual wind speed, taking into account the change in wind energy potential by months, are presented. It is determined that the variable nature of solar and wind resources can be fully compensated by optimal integration of two different sources into a single energy system.

Possibilities of using modular high-temperature reactors for the conversion of organic fuels.

Viacheslav Dubkovskiy — 2024-10-22

The possibility of using small modular high-temperature gas-cooled nuclear reactors for the conversion of fuel fossils is considered. The use of high-temperature gas-cooled nuclear reactors as a source of high-potential thermal energy for the conversion of organic fuels is the latest technology that allows processing primary organic raw materials (coal, natural gas, oil, shale) into secondary energy carriers and secondary raw materials for the chemical, metallurgical and other types of industry: hydrogen, converter gas, methanol, reducing gas, carbon black, coke, etc. An important place in the development of high-temperature reactors is occupied by low-power modular reactors, the thermal power of which is in the range of 200...600 MW. Existing and planned modular reactors and their main parameters are given. The possibility of using modular high-temperature reactors for natural gas conversion and coal gasification is justified. Technological schemes of energy technology installations with steam conversion of natural gas and gasification of coal, intended only for ensuring the processes of conversion and gasification, as well as for the production of electrical energy, are given. The method of calculating the energy efficiency of the technological part of the installations and the installation as a whole is described. Quantitative indicators of the energy efficiency of the plants and their parts have been calculated, which lie within 65...80% depending on the technological scheme and the type of technological raw materials and significantly exceed the efficiency of nuclear gas turbine plants at the same temperature of helium at the reactor exit as the considered plants.

Improving the reliability of heat supply systems in the conditions of power outage.

Oleksandr Klymchuk — 2024-12-14

The paper analyzes the current state of municipal heat power engineering with centralized heat supply systems in emergency power outages. An overview of existing approaches to solving the issue of reliable provision of electricity by centralized heat sources is carried out. The urgency of complex solution of problems of reliability of energy supply of communal services objects both heat and electricity is given. At the same time, it is proposed to minimize the location of heat and electricity generators, to coordinate the modes of consumption of different types of energy resources. One of the directions of solving the questions proposed the use of cogeneration plants that are able to provide utilities not only heat, but also electricity. The priority for the location of cogeneration plants is offered by heating boiler houses, which organized a cell release of combustion products, as well as a system of distribution of heat carriers. To solve these issues, a scheme for integrating the cogeneration plant into a centralized heat supply system based on the district heating boiler house and the use of heat pumps was developed. The comparative analysis of energy efficiency of the proposed solutions is carried out by the value of the coefficient of fuel heat use. According to the task, an analysis of the use of cogeneration installations in energy supply systems of communal services complexes was carried out. It is proposed to use heat pumps to improve the efficiency of the system of joint heat and electricity production. For the selected modes of operation of the proposed system, an analysis of the efficiency of combined heat and electricity production was carried out. It is shown that application in the heat pump scheme is able to provide an increase in the share of additional heat sources to 50% in the boiler room balance, and, accordingly, to increase the energy efficiency index by 1.3 times.

Assessment of stability of natural circulation in the first circuit of small modular reactors.

Vyacheslav Kovalchuk — 2024-11-27

The work contains the results of the study of the influence of the architecture and operating parameters of the water-based modular reactor plant on its functioning in the mode of natural circulation of the coolant of the first circuit. The purpose of the study is to assess the possibility of organizing a natural circulation regime in the first circuit of a modular reactor with the given structure, geometry and thermal parameters. In the world, there are more than 50 low-power reactor projects at various stages of development, designed to meet the energy needs of regions with different levels of resource availability. The expected advantages of modular designs, along with the possibility of their serial production, include the flexibility of operating modes and increased safety due to the use of natural circulation of the coolant in the first circuit. The methodology is based on the classical principles of the balance of forces acting on the system in a steady state, which is the closed loop of the reactor plant during operation. The necessary characteristics of the circuit components (reactor and steam generator) were obtained as a result of their calculations for the selected basic module SMR 160. The technological structure of the energy facility was obtained by a large-scale analysis of illustrative materials. Comparison of the calculated values of the driving pressure (19412 Pa) and total losses in the circuit (27302 Pa) showed that to organize a stable natural circulation mode, it is necessary to optimize the structure of the installation by jointly varying the parameters of the architecture and the operating characteristics of the circuit, which ensures flexible operating modes. The results of the study confirmed the feasibility of applying the principle of balance of forces to assess the possibility of organizing natural circulation in a closed loop. The paper proposes a methodology for pre-design joint analysis of the architecture of the power module and its operating parameters to ensure reliable and safe operation of a nuclear facility in autonomous conditions.

Modern trends in the digitalization of processes at construction enterprises.

Andriy Chumachenko — 2024-11-19

The article explores the current trends in the digitalization of processes at construction enterprises in Ukraine, which require assessment in the context of the country’s post-war recovery. The degree of integration of digital technologies into various stages of the construction project life cycle is examined. The current financial and economic position of enterprises in the construction sector is analysed and it is identified as a qualifying factor that influences on the innovative and investment renewal of the sector’s activities. The use of digitalization as a benchmark for evaluating developers is proposed, which will contribute to increasing the transparency and reliability of their financial and economic activities. The SWOT analysis of the digitalization processes in construction enterprises is suggested as a study of a complex set of factors that set the vector for the sector’s development, creating the preconditions for the transition of construction business participants to digital standards and establishing it as a relevant addition to the dialogue about the digital prospects of the construction sector. Conducting a thorough analysis of the strengths and weaknesses, advantages, and disadvantages of digitalization processes in design at construction enterprises provides an objective assessment of construction company management’s readiness to use modern tools to improve a range of business processes. The need for reforming business process management approaches at construction enterprises on the basis of digitalization is emphasized, as it is one of the key factors for ensuring the sustainable development of construction companies. The work highlights the importance of supporting digital changes for the economic revival of the country and the competitiveness of construction enterprises in the context of Industry 4.0.

Modeling issues of low-speed elevator motor of biinductor type.

Andrii Boiko — 2024-12-12

Most of the electricity used in the operation of elevators consumes elevator electric drive, so the main focus in the design of modern elevator designs is to improve the energy characteristics of winches and their control systems. Electric drives of passenger elevators, which are operated, include single or two-speed asynchronous electric motors and worm gearboxes. In modern elevator construction, there are two trends in improving the electric drives of machine drives, namely, ensuring smooth acceleration and braking of the working body; transition from an electric drive, in which a mechanical gearbox is used, to a gearless drive. This allows you to increase the efficiency by eliminating the element with a low efficiency. One of the ways to solve the problem of synthesis of a modern gearless elevator electric drive is the possibility of using a low-speed biinductor-type electric motor (biinductor electric motor) with a non-winding cylindrical rotor. The work conducted a technical analysis of the requirements for electric passenger elevators. The advantages of gearless elevator electric drives and the actual needs for low-speed drive engines are indicated. The possibility, in this capacity, of using an electric motor of biinductor type with a non-winding cylindrical rotor is considered. It is noted that the design scheme of the biinductor motor provides an increase in the specific values of power and torque, this is especially important with reduced rated speeds of gearless elevator winches. The basic structural parameters of the engine of biinductor type are considered and its equivalent structural scheme is proposed. The possibility of moving to a simplified structural scheme of the engine is shown, which, according to a number of assumptions, makes it possible to format any transfer function, both for the control and for the disturbing effect. Mathematical description of proposed electric motor is made as complex electromechanical system with multidimensional nonlinear objects.

Integration of heat pumps with heat extraction from the soil and air into building heating systems.

Yurii Riepin — 2024-12-13

The paper reviews the current state of heat supply systems for residential and public buildings. The need to use alternative energy sources for heat supply in residential and public buildings is shown. Various heat pump systems and heat sources are analyzed. The most common heat sources for heat supply systems using heat pumps are identified, namely the soil and outside air. For heat pump systems with heat extraction from the soil, various approaches to heat extraction are analyzed. The advantages and problems of using heat pump systems with heat extraction from the outside air and soil are characterized. It is shown that energy saving measures require an integrated approach. The use of heat pump systems in combined heat supply systems should be addressed together with the issues of thermal operating modes of buildings. It is proven that in order to improve the process of implementing heat pump systems, it is necessary to increase their profitability by increasing the share of replacing traditional energy resources with renewable energy sources. To study the efficiency of heat pumps with different types of heat sources, the paper presents a mathematical model of the operation of a heat pump with heat extraction from the outside air and the soil. For buildings with similar technical data, a study of the operation of combined heat supply systems using heat pumps with heat extraction from the outside air and the soil throughout the year was conducted. Based on the data obtained, comparative graphs of heat pump operation were constructed, and an analysis of the efficiency of the operating modes of the main equipment was conducted. Based on the results of the analysis, conclusions were drawn that show the zones of effective operation of heat pumps of different types. The results obtained allowed us to assess the efficiency of heat pump systems with different heat sources, and provide an opportunity for further research in the direction of developing recommendations for the use of heat pumps in combined heat supply systems.

Qualification of nuclear reactor nominal power upgrades.

Volodymyr Skalozubov — 2024-12-15

In extreme wartime conditions due to damage/destruction/occupation of a number of power generating facilities and continuous damage/destruction of the critical energy infrastructure of Ukraine, the priority and urgent task of the operating organization of nuclear power plants (State Enterprise "National Nuclear Energy Generating Company “Energoatom”) is to increase the efficiency of safe operation of operating nuclear power units based on qualification and implementation of strategies for increased nominal power and duration of the fuel campaign of nuclear reactors. An analysis of known approaches to substantiating (qualifying) strategies for operating nuclear reactors of the VVER/PWR type at increased nominal power is presented. It is recognized that the main shortcomings of known approaches to qualifying nuclear reactor core modernizations lie in the dependence of the qualification results on the methods of implementing the strategy for operating nuclear power plants in increased nominal power modes, as well as on the effects of the difference in deterministic codes and/or code users, that ultimately complicates the objective interpretation of the qualification results. A criterion-based method for qualifying the strategy for operating nuclear reactors at increased nominal power based on the modernization of the thermophysical properties of nuclear fuel and the structural and technical parameters of fuel elements has been developed, which eliminates the influence of the effects of the difference in deterministic codes and/or code users and takes into account the conditions for ensuring safety regarding the maximum permissible temperatures of fuel and nuclear fuel claddings.

Technological dynamics of non-stationary systems during finishing intermittent cutting.

Anna Balaniuk — 2024-11-09

In this work the stability and peculiarities of oscillations of unsteady technological systems during finishing boring in complex cutting modes - machining of discontinuous surfaces or deep holes of small diameter, etc. are studied. In mechanical engineering technology such operations are performed quite often, and with ever-increasing requirements for machining accuracy. It is clear that in the first case periodically repeated transient processes of tool plunging and tool exit cause impact effects on the cutter, which leads to chipping of cutting edges, increased wear and negatively affects the output machining accuracy. The elastic-dissipative-inertial system (EDIS) closed to the cutting process becomes unsteady not only due to the interruption of links, but also due to the periodic change of parameters. In this case, dynamic models are described by differential equations with variable coefficients. Systems with periodically changing parameters are called nonstationary, and oscillations are called parametric. In modern engineering technology, many problems arise in which dynamic factors dominate. Parametric oscillations are described by Mathieu equations, which reflect complex dynamic processes such as resonances and auto oscillations. Experiments were carried out on the bench to study oscillations during boring of steel, cast iron and bronze specimens with interrupted surfaces, with the number of interruptions per revolution varying from 1 to 20. The character of oscillations is established and the conditions of stability of solutions on the Ains-Strett diagram are reflected. A methodology of constructing time forms of oscillations has been developed, which makes it possible to predict amplitudes, frequencies and resonance phenomena in intermittent cutting.

Methods of creating prestress in span structures and features of their calculation.

Ihor Prokopovych — 2024-11-21

The topic of the work is related to the possibility of investigating the influence of the curvature of a prestressed crane bridge on its bearing capacity. In the work, the authors propose a new structural-technological solution for prestressing the crane bridge, which allows avoiding the main shortcomings inherent in the currently used structures. The proposed design also avoids the constant stress-deformed state of the beam, where the magnitude of the unloading moment depends on the magnitude of the working load. For a positive consideration of the given task, there is a need to obtain an exact equation of the crane bridge deflection curve. Such a task requires the development of a new mathematical model, as well as the development and refinement of already existing mathematical models of preformed beam systems. This is the purpose of this work. The paper proposes a new mathematical model based on the general theory of stability of elastic systems. During its development, the real conditions of the construction of the crane bridge were taken into account. The universal equations of the deflection curve of the beam with the initial curvature are obtained, which make it possible to investigate its stress-strain behavior under the simultaneous action of loads on the beam in the plane of the suspension of the load simultaneously with an axial eccentric load. The results obtained in this work can be taken into account when determining the geometric characteristics of beam sections, as well as for improving the calculation methods for the design of span beam systems at the stages of their design, as well as in real operation conditions. In addition, the recommendations given by the authors can be applied in the repair of crane bridges, their modernization in order to increase the load capacity, as well as increase the service life of the lifting machine without dismantling.

Loss of stability and energy of metallic vacuum membranes of sealing agents. Some technical systems operate in the presence of vacuum.

Oleksandr Vatrenko — 2024-11-17

Some technical systems operate in the presence of vacuum. To control the vacuum depth, vacuum control sensors are often used, which are rather complex and expensive electrical devices. The paper investigates the energy capabilities of metal membranes of vacuum closures, which, in the process of controlled loss of stability, can perform the function of vacuum sensors in packaging without the use of special sensors. Studies have shown that membranes stamped on the field of closures lose their stability due to pressure drop, and the shape is restored due to the transformation energy that occurs in them as a result of the loss of stability. The value of this energy depends on the thickness of the membrane. The parameters of the membranes of different tinplate thicknesses were obtained and the corresponding graphical dependencies were constructed. According to the research, with a decrease in the membrane thickness, the transformation energy increases, while the pressure of loss of stability decreases. In the process of digital modelling, it is proposed to estimate the level of internal energy of metal membranes by comparing the energy levels of different membranes in possible equilibrium states. The proposed method is based on the mathematical modelling of the energy levels of the membrane equilibrium state, performed using the energy method from the theory of plates and shells. The energy levels of membranes of different tinplate thicknesses in the state of loss of stability are obtained, each of which has its own minimum. Based on the results of digital modelling, the energy component was analysed and the minimum energy values during the loss of membrane stability were calculated for membranes of different thicknesses. It is shown that an energy jump occurs during the transition from one equilibrium state to another. During the energy jump, due to the release of the transformation energy, the membrane moves instantaneously in space. It is proposed to estimate the energy levels of metal membranes by the method, according to which the energy levels of different membranes in equilibrium states are compared.

Implementation of the hybrid binarisation method for thermogram analysis.

Gennady Oborsky — 2024-12-10

The object of this study is thermograms obtained as a result of thermal imaging control of the machining process during the external turning operation. The implementation of thermal imaging control enables rapid visualisation of the thermal state of the external surfaces of the tool, workpiece, and chips in the cutting zone by obtaining thermograms. The article presents developments in creating a hybrid binarisation method for thermograms to enable further processing using neural networks. To realisation this project, an analysis of existing technologies and algorithms was conducted, selecting those that, in the authors' opinion, have the highest efficiency. A working prototype was developed using the Python 3.13 and the OpenCV framework for processing raster images. Due to the specific format of thermograms, the first step involved converting colour images into monochrome. The second step then applied a fixed binarisation method to highlight the hottest areas corresponding to the cutting zone (the contact area between the tool and the workpiece). The third step involves adaptive binarisation, which processes the highlighted frame area using Gaussian distribution, as a result, the necessary objects in the frame-corresponding to the cutting tool, workpiece, and occasionally hot chips-are accurately highlighted. The resulting algorithm turned out to be simple and fast, despite the execution of two sequential binarization algorithms, while maintaining an adequate level of frame conversion accuracy. This allows its further use in training neural networks on the obtained dataset.

An Express Method of Forecasting the Development of Degradation Processes in Ship’s Mechanisms Using Current Information through On-Board Instruments.

Kostiantyn Boriak — 2024-12-12

The article proposes a novel express method for the prompt evaluation of the current technical condition of a combat boat’s powerplant to forecast the development of degradation processes in the assemblies (mechanisms) of this powerplant during operation in order to prevent the occurrence of unforeseen failures when the boat performs her combat missions, as well as to adjust the timing of maintenance (repairs) based on the analysis of the monitored values of the determining parameters. One of the key roles in the method proposed is played by the control panels of the on-board system for monitoring the operating parameters of the boat’s powerplant. It is supposed that the developed diagnostic express method of will become an auxiliary source of current technical information that is provided by the ship’s (boat’s) crew members to the maintenance and repair department personnel for further analysis and decision-making when the boat comes back to the harbor. The article presents the results of full-scale experiments conducted to determine the most informative parameters for the prompt evaluation of the technical condition of the components of a ship’s powerplant, the values of which change through time. A detailed analysis of the parametric values generated by the on-board technical condition monitoring system is shown, taking into account the shift in the period of the prompt evaluation to the stage of heating-up of the unit (mechanism) using an improved diagnostic technique based on the empirical criterion of the rate of change in the values of the determining parameters in a fixed period of time. The obtained intermediate values of the rate of change in certain operational parameters are presented and ways of obtaining the limits of critical values are determined, approaching which increases the probability of loss of operability of the diesel engine and therefore increases the risk of the ship’s inability to perform her tasks.

Synthesis of a neural regulator and experimental stability study for an adaptive quadcopter control system.

Volodymyr Tigariev — 2024-11-21

When solving a number of complex manipulation tasks, it is advisable to take into account the nonlinear dynamics of the control object. Such tasks include, in particular, the control of large space-based manipulators, as well as ground-based manipulation systems used in construction and in the aftermath of accidents and disasters. For such manipulation systems, the control task is complicated by the fact that the dynamics of the controlled structure is very complex and, in most cases, cannot be mathematically described. In this regard, methods based on solving the inverse dynamics problem cannot always be applied. The use of PID controllers, which are widely used in most industrial applications, also allows us to take into account the peculiarities of the motion dynamics of such systems. There are also problems with ensuring stability, including under the influence of external factors that are not known in advance. A new direction in this area is related to the use of neural networks, which can estimate the dynamics of the system in real time. On the other hand, the use of sliding modes in control systems ensures the independence of the control process from both external influences and parametric disturbances. The combination of these methods allows to create a system that can eliminate some of the disadvantages of each method. In this article, we develop a control method based on an adaptive neural network tuning algorithm. The proposed method allows controlling the system without a priori information about the structure and parameters of the dynamic model of the controlled object. Adaptive algorithms are used to determine the coefficients of the neural network controller, which allow its adjustment as a normal functioning of the system. The stability conditions of such a control system are obtained using the Lyapunov method. The effectiveness of the proposed control method is confirmed by the results of modeling the control system in MATLAB, as well as by experimental studies of robotic systems.

Model of automated control of the electric power system to ensure reliability and fficiency of power supply in the event of disturbances and imbalances.

Viktor Zubak — 2024-11-03

The article presents a simulation model of automated control for the electric power system that ensures reliable and efficient power supply under disturbances and imbalances. This work involves the development of an informational model of the electric power system, state models of objects, and data flow diagrams of actions. The developed electric power system models allow for the analysis of interactions between objects and processes and quickly identify potential issues, optimizing the system's operation to enhance its reliability and efficiency. One of the key aspects is the system's adaptability, which enables prompt responses to changes in power balance, critical for ensuring the stable operation of the electric power system. The proposed model ensures reliable and efficient power supply by considering the specifics of the interaction between objects and processes within the system. The integration of these objects allows the system to adapt to both internal and external changes, such as disturbances or imbalances, ensuring stable operation even under unpredictable conditions. The article discusses the main principles of operation of each object and their interaction with one another. The state models reflect the lifecycle of objects in the occurrence of events within the electric power system, allowing for more accurate predictions of their behavior and effective system management. The developed data flow diagrams of actions facilitate convenient and efficient modeling of the functional nature of actions of objects, reflecting crucial processes to maintain the stability of the power system. The use of object-oriented models significantly improves the detection of issues and the optimization of the operation of individual elements within the power system. This reduces the risks of unauthorized disconnections and contributes to accurate planning and adjustment of the energy system's operation, taking into account changing conditions. The application of such models ensures effective decision-making and allows for the rapid restoration of power and voltage balance within the system, guaranteeing uninterrupted power supply even under disturbances.