Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item Energy conversion in the working nozzle of a pneumatic abrasive-jet unit(Sumy State University, 2025) Бага, Вадим Миколайович; Baha, Vadym Mykolaiovych; Pitel, J.The article investigates the working processes in the channels with relatively simple geometry, such as working nozzles and seals designed to regulate the working flow jet passing through them. The main aim was to solve an essential scientific and technological problem of improving flow part nozzle performance in the pneumoabrasive units by applying the results of the study of energy conversion mechanism, namely, the conversion of compressed air potential energy into kinetic energy of the nozzle outlet jet. Hydrodynamic methods of flow part profiling, CFD modeling, and a physical experiment were applied. The methods for rational choice of the working nozzle geometry and its operating mode were also carried out. The designs of working nozzles for hydro-pneumatic units, their systems, and elements were developed and improved. The air nozzle geometry was adapted to operate in the pneumo-abrasive unit, with the air abrasive mixture being its medium. River sand, with a grain size of about 0.5 mm, was used as an abrasive material. The numerical studies of the air-abrasive mixture flow in the nozzle flow part resulted in gaining detailed information about all the elements of its structure in the flow and beyond it within a wide range of operating modes due to the application of the ANSYS software. As a result, a new approach to working nozzles profiling based on providing a proper air-abrasive mixture flow movement with a minimum hydraulic axial and circumferential resistance was developed. This made it possible to increase both the air-abrasive mixture flow rate from a nozzle and its consumption factor value. The impact patterns of nozzle geometry and operating modes on its flow structure and other indicators considered while designing and upgrading the flow parts of the jet-abrasive nozzles were found. Overall, a new design for a working nozzle with better energy performance was developed.Item Effect of erosion on surface roughness and hydromechanical characteristics of abrasive-jet machining(Sumy State University, 2024) Baha, V.; Pitel, J.; Павленко, Іван Володимирович; Pavlenko, Ivan VolodymyrovychThe article contains the fundamental results of the experimental and numerical investigations for pneumoabrasive unit nozzles with different geometries. The research was purposed by the pressing need to develop an inexpensive and effective working nozzle design of the air-abrasive unit which can be applied for surface processing before some technological processes are performed, as well as for surface coating, descaling after thermal treatment, processing of hollow holes of the crankshafts, smoothing of the inner surfaces of the narrow channels between the impeller blades after electric discharge machining for ultrahigh-pressure combination compressors. Several designs were considered, ranging from the simplest to those with a complicated inner channel geometry. The impact of the nozzle material and challenging inner surface application on its characteristics has also been studied. The research was done using the application of modern CFD complexes for numerical modeling of the air-abrasive mixture discharge from the working nozzle of the pneumo-abrasive unit. In addition, physical experimentation was provided. The methods applied in the research allow for profound, systematic research of spraying units operating on the air-abrasive mixture within a wide range of geometrical and mode parameters. The novelty of the gained results lies in the development of the mathematical model of the pneumo-abrasive nozzle operating process, the working out of a cheaper nozzle design, getting information about air-abrasive mixture distribution along the nozzle length, giving practical recommendations for calculation and designing a working nozzle for the jet-abrasive unit.Item The influence of the design features of the submersible pump rotor on the vibration reliability(Sumy State University, 2024) Маківський, Олексій Сергійович; Makivskyi, Oleksii Serhiiovych; Кондусь, Владислав Юрійович; Kondus, Vladyslav Yuriiovych; Pitel, J.; Сотник, Микола Іванович; Sotnyk, Mykola Ivanovych; Андрусяк, Владислав Олегович; Andrusiak, Vladyslav Olehovych; Полковниченко, Вадим Валентинович; Polkovnychenko, Vadym Valentynovych; Муштай, Максим Валерійович; Mushtai, Maksym ValeriiovychPumping equipment consumes about 20 % of the electrical energy produced by humankind. A significant, even drastic, reduction in the weight and size indicators of pumping equipment leads to a decrease in the cost price and, therefore, competitiveness of such products in the market. Simultaneously, it makes it possible to use more valuable and high-quality construction materials and technologies that improve the reliability of equipment and its energy efficiency, which in turn is a clear step in solving many UN Sustainable Development Goals (SDGs). According to the research results, it was proved that by increasing the frequency of the drive, it is possible to reduce the mass and size indicators of the submersible pump for the needs of the critical infrastructure sector by reducing the number of stages. Mainly, the amplitudes of oscillations near the rotation frequency are 12–22 % and do not exceed 35 % of the gaps in the seals, as required by the available international standards to ensure the guaranteed vibration reliability of the pump. Overall, using a bearingless support design will significantly increase the reliability of the developed pump.